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PHP Interview Questions

noreply@blogger.com (Anonymous) — Thu, 27 Mar 2014 03:05:00 -0700

Interview Questions

Top 200 PHP interview questions and answers are below

Questions : 1 Who is the father of PHP ?

Answers : 1 Rasmus Lerdorf is known as the father of PHP.

Questions : 2 What is the difference between $name and $$name?

Answers : 2 $name is variable where as $$name is reference variable
like $name=sonia and $$name=singh so $sonia value is singh.

Questions : 3 How can we submit a form without a submit button?

Answer : 3 Java script submit() function is used for submit form without submit button
on click call document.formname.submit()

Questions : 4 In how many ways we can retrieve the data in the result set of
MySQL using PHP?

Answer : 4 We can do it by 4 Ways
1. mysql_fetch_row. , 2. mysql_fetch_array , 3. mysql_fetch_object
4. mysql_fetch_assoc

Questions : 5 What is the difference between mysql_fetch_object and
mysql_fetch_array?

Answers : 5 mysql_fetch_object() is similar tomysql_fetch_array(), with one difference -
an object is returned, instead of an array. Indirectly, that means that
you can only access the data by the field names, and not by their
offsets (numbers are illegal property names).

Questions : 6 What are the differences between Get and post methods.

Answers : 6

There are some defference between GET and POST method
1. GET Method have some limit like only 2Kb data able to send for request
But in POST method unlimited data can we send
2. when we use GET method requested data show in url but
Not in POST method so POST method is good for send sensetive request

Questions : 7 How can we extract string "pcds.co.in " from a string "http://info@pcds.co.in
using regular expression of PHP?

Answers : 7 preg_match("/^http:\/\/.+@(.+)$/","http://info@pcds.co.in",$matches);
echo $matches[1];

Questions : 8 How can we create a database using PHP and MySQL?

Answers : 8 We can create MySQL database with the use of
mysql_create_db("Database Name")

Questions : 9 What are the differences between require and include?

Answers : 9 Both include and require used to include a file but when included file not found
Include send Warning where as Require send Fatal Error .

Questions : 10 Can we use include ("xyz.PHP") two times in a PHP page "index.PHP"?

Answers : 10 Yes we can use include("xyz.php") more than one time in any page. but it create a prob when xyz.php file contain some funtions declaration then error will come for already declared function in this file else not a prob like if you want to show same content two time in page then must incude it two time not a prob

Questions : 11 What are the different tables(Engine) present in MySQL, which one is default?

Answers : 11 Following tables (Storage Engine) we can create
1. MyISAM(The default storage engine IN MYSQL Each MyISAM table is stored on disk in three files. The files have names that begin with the table name and have an extension to indicate the file type. An .frm file stores the table format. The data file has an .MYD (MYData) extension. The index file has an .MYI (MYIndex) extension. )
2. InnoDB(InnoDB is a transaction-safe (ACID compliant) storage engine for MySQL that has commit, rollback, and crash-recovery capabilities to protect user data.)
3. Merge
4. Heap (MEMORY)(The MEMORY storage engine creates tables with contents that are stored in memory. Formerly, these were known as HEAP tables. MEMORY is the preferred term, although HEAP remains supported for backward compatibility. )
5. BDB (BerkeleyDB)(Sleepycat Software has provided MySQL with the Berkeley DB transactional storage engine. This storage engine typically is called BDB for short. BDB tables may have a greater chance of surviving crashes and are also capable of COMMIT and ROLLBACK operations on transactions)
6. EXAMPLE
7. FEDERATED (It is a storage engine that accesses data in tables of remote databases rather than in local tables. )
8. ARCHIVE (The ARCHIVE storage engine is used for storing large amounts of data without indexes in a very small footprint. )
9. CSV (The CSV storage engine stores data in text files using comma-separated values format.)
10. BLACKHOLE (The BLACKHOLE storage engine acts as a "black hole" that accepts data but throws it away and does not store it. Retrievals always return an empty result)

Questions : 12 What is use of header() function in php ?

Answers : 12 The header() function sends a raw HTTP header to a client.We can use herder()
function for redirection of pages. It is important to notice that header() must
be called before any actual output is seen..

Questions : 13 How can I execute a PHP script using command line?

Answers : 13 Just run the PHP CLI (Command Line Interface) program and
provide the PHP script file name as the command line argument.

Questions : 14 Suppose your Zend engine supports the mode Then how can u
configure your PHP Zend engine to support mode ?

Answers : 14 In php.ini file:
set
short_open_tag=on
to make PHP support

Questions : 15 Shopping cart online validation i.e. how can we configure Paypal,
etc.?

Answers : 15 Nothing more we have to do only redirect to the payPal url after
submit all information needed by paypal like amount,adresss etc.

Questions : 16 What is meant by nl2br()?

Answers : 16 Inserts HTML line breaks (
) before all newlines in a string.

Questions : 17 What is htaccess? Why do we use this and Where?

Answers : 17 .htaccess files are configuration files of Apache Server which provide
a way to make configuration changes on a per-directory basis. A file,
containing one or more configuration directives, is placed in a particular
document directory, and the directives apply to that directory, and all
subdirectories thereof.

Questions : 18 How we get IP address of client, previous reference page etc ?

Answers : 18 By using $_SERVER['REMOTE_ADDR'],$_SERVER['HTTP_REFERER'] etc.

Questions : 19 What are the reasons for selecting lamp (Linux, apache, MySQL,
PHP) instead of combination of other software programs, servers and
operating systems?

Answers : 19 All of those are open source resource. Security of Linux is very
very more than windows. Apache is a better server that IIS both in
functionality and security. MySQL is world most popular open source
database. PHP is more faster that asp or any other scripting language.

Questions : 20 How can we encrypt and decrypt a data present in a MySQL table
using MySQL?

Answers : 20 AES_ENCRYPT () and AES_DECRYPT ()

Questions : 21 How can we encrypt the username and password using PHP?

Answers : 21

The functions in this section perform encryption and decryption, and
compression and uncompression:

encryption	decryption
AES_ENCRYT()	AES_DECRYPT()
ENCODE()	DECODE()
DES_ENCRYPT()	DES_DECRYPT()
ENCRYPT()	Not available
MD5()	Not available
OLD_PASSWORD()	Not available
PASSWORD()	Not available
SHA() or SHA1()	Not available
Not available	UNCOMPRESSED_LENGTH()

Questions : 22 What are the features and advantages of object-oriented
programming?

Answers : 22 One of the main advantages of OO programming is its ease of
modification; objects can easily be modified and added to a system there
by reducing maintenance costs. OO programming is also considered to be
better at modeling the real world than is procedural programming. It
allows for more complicated and flexible interactions. OO systems are
also easier for non-technical personnel to understand and easier for
them to participate in the maintenance and enhancement of a system
because it appeals to natural human cognition patterns.
For some systems, an OO approach can speed development time since many
objects are standard across systems and can be reused. Components that
manage dates, shipping, shopping carts, etc. can be purchased and easily
modified for a specific system

Questions : 23 What are the differences between procedure-oriented languages and
object-oriented languages?

Answers : 23 There are lot of difference between procedure language and object oriented like below
1>Procedure language easy for new developer but complex to understand whole software as compare to object oriented model
2>In Procedure language it is difficult to use design pattern mvc , Singleton pattern etc but in OOP you we able to develop design pattern
3>IN OOP language we able to ree use code like Inheritance ,polymorphism etc but this type of thing not available in procedure language on that our Fonda use COPY and PASTE .

Questions : 24 What is the use of friend function?

Answers : 24 Sometimes a function is best shared among a number of different
classes. Such functions can be declared either as member functions of
one class or as global functions. In either case they can be set to be
friends of other classes, by using a friend specifier in the class that
is admitting them. Such functions can use all attributes of the class
which names them as a friend, as if they were themselves members of that
class.
A friend declaration is essentially a prototype for a member function,
but instead of requiring an implementation with the name of that class
attached by the double colon syntax, a global function or member
function of another class provides the match.

Questions : 25 What are the differences between public, private, protected,
static, transient, final and volatile?

Answer : 25 Public: Public declared items can be accessed everywhere.
Protected: Protected limits access to inherited and parent
classes (and to the class that defines the item).
Private: Private limits visibility only to the class that defines
the item.
Static: A static variable exists only in a local function scope,
but it does not lose its value when program execution leaves this scope.
Final: Final keyword prevents child classes from overriding a
method by prefixing the definition with final. If the class itself is
being defined final then it cannot be extended.
transient: A transient variable is a variable that may not
be serialized.
volatile: a variable that might be concurrently modified by multiple
threads should be declared volatile. Variables declared to be volatile
will not be optimized by the compiler because their value can change at
any time.

Questions : 26 What are the different types of errors in PHP?

Answer : 26 Three are three types of errors:1. Notices: These are trivial,
non-critical errors that PHP encounters while executing a script â€“ for
example, accessing a variable that has not yet been defined. By default,
such errors are not displayed to the user at all â€“ although, as you will
see, you can change this default behavior.2. Warnings: These are more serious errors â€“ for example, attempting
to include() a file which does not exist. By default, these errors are
displayed to the user, but they do not result in script termination.3. Fatal errors: These are critical errors â€“ for example,
instantiating an object of a non-existent class, or calling a
non-existent function. These errors cause the immediate termination of
the script, and PHP's default behavior is to display them to the user
when they take place.

Questions : 27 What is the functionality of the function strstr and stristr?

Answers : 27 strstr Returns part of string from the first occurrence of needle(sub string that we finding out ) to the end of string.
$email= 'sonialouder@gmail.com';
$domain = strstr($email, '@');
echo $domain; // prints @gmail.com
here @ is the needle
stristr is case-insensitive means able not able to diffrenciate between a and A

Questions : 28 What are the differences between PHP 3 and PHP 4 and PHP 5?

Answer : 28 There are lot of difference among these three version of php
1>Php3 is oldest version after that php4 came and current version is php5 (php5.3) where php6 have to come
2>Difference mean oldest version have less functionality as compare to new one like php5 have all OOPs concept now where as php3 was pure procedural language constructive like C
In PHP5 1. Implementation of exceptions and exception handling
2. Type hinting which allows you to force the type of a specific argument
3. Overloading of methods through the __call function
4. Full constructors and destructors etc through a __constuctor and __destructor function
5. __autoload function for dynamically including certain include files depending on the class you are trying to create.
6 Finality : can now use the final keyword to indicate that a method cannot be overridden by a child. You can also declare an entire class as final which prevents it from having any children at all.
7 Interfaces & Abstract Classes
8 Passed by Reference :
9 An __clone method if you really want to duplicate an object
10 Numbers of Functions Deprecated in php 5.x like ereg,ereg_replace,magic_quotes_runtime, session_register,register_globals, split(), call_user_method() etc

Questions : 29 How can we convert asp pages to PHP pages?

Answer : 29 there are lots of tools available for asp to PHP conversion. you can
search Google for that. the best one is available athttp://asp2php.naken.cc./

Questions : 30 What is the functionality of the function htmlentities?

Answer : 30 Convert all applicable characters to HTML entities
This function is identical to htmlspecialchars() in all ways, except
with htmlentities(), all characters which have HTML character entity
equivalents are translated into these entities.

Questions : 31 How can we get second of the current time using date function?

Answer : 31 $second = date("s");

Questions : 32 How can we convert the time zones using PHP?

Answer : 32

By using date_default_timezone_get and date_default_timezone_set function on PHP 5.1.0

', date(DATE_RFC1123, $stamp) ,'

';?> Questions : 33What is meant by urlencode and urldocode? Answer : 33URLencode returns a string in which all non-alphanumeric characters
except -_. have been replaced with a percent (%)
sign followed by two hex digits and spaces encoded as plus (+)
signs. It is encoded the same way that the posted data from a WWW form
is encoded, that is the same way as in application/x-www-form-urlencoded media type.

urldecode decodes any %##
encoding in the given string.

Questions : 34What is the difference between the functions unlink and unset? Answer : 34unlink() deletes the given file from the file system.
unset() makes a variable undefined. Questions : 35How can we register the variables into a session? Answer : 35$_SESSION['name'] = "sonia"; Questions : 36How can we get the properties (size, type, width, height) of an
image using PHP image functions? Answer : 36To know the Image type use exif_imagetype () function
To know the Image size use getimagesize () function
To know the image width use imagesx () function
To know the image height use imagesy() function t Questions : 37How can we get the browser properties using PHP? Answer : 37By using


$_SERVER['HTTP_USER_AGENT']
variable.

Questions : 38What is the maximum size of a file that can be uploaded using PHP
and how can we change this? Answer : 38By default the maximum size is 2MB. and we can change the following
setup at php.iniupload_max_filesize = 2M Questions : 39How can we increase the execution time of a PHP script? Answer : 39by changing the following setup at php.inimax_execution_time = 30
; Maximum execution time of each script, in seconds Questions : 40How can we take a backup of a MySQL table and how can we restore
it. ? Answer : 40To backup: BACKUP TABLE tbl_name[,tbl_nameâ€¦] TO
'/path/to/backup/directory'
RESTORE TABLE tbl_name[,tbl_nameâ€¦] FROM '/path/to/backup/directory'mysqldump: Dumping Table Structure and DataUtility to dump a database or a collection of database for backup or
for transferring the data to another SQL server (not necessarily a MySQL
server). The dump will contain SQL statements to create the table and/or
populate the table.
-t, â€“no-create-info
Don't write table creation information (the CREATE TABLE statement).
-d, â€“no-data
Don't write any row information for the table. This is very useful if
you just want to get a dump of the structure for a table! Questions : 41How can we optimize or increase the speed of a MySQL select
query? Answer : 41

first of all instead of using select * from table1, use select
column1, column2, column3.. from table1
Look for the opportunity to introduce index in the table you are
querying.
use limit keyword if you are looking for any specific number of
rows from the result set.

Questions : 42How many ways can we get the value of current session id? Answer : 42session_id() returns the session id for the current session. Questions : 43How can we destroy the session, how can we unset the variable of
a session? Answer : 43session_unregister â€” Unregister a global variable from the current
session
session_unset â€” Free all session variables Questions : 44How can we set and destroy the cookie n php? Answer : 44By using setcookie(name, value, expire, path, domain); function we can set the cookie in php ;
Set the cookies in past for destroy. like
setcookie("user", "sonia", time()+3600); for set the cookie
setcookie("user", "", time()-3600); for destroy or delete the cookies; Questions : 45How many ways we can pass the variable through the navigation
between the pages? Answer : 45

GET/QueryString
POST

Questions : 46What is the difference between ereg_replace() and eregi_replace()? Answer : 46eregi_replace() function is identical to ereg_replace() except that
this ignores case distinction when matching alphabetic
characters.eregi_replace() function is identical to ereg_replace()
except that this ignores case distinction when matching alphabetic
characters. Questions : 47What are the different functions in sorting an array? Answer : 47Sort(), arsort(),
asort(), ksort(),
natsort(), natcasesort(),
rsort(), usort(),
array_multisort(), and
uksort(). Questions : 48How can we know the count/number of elements of an array? Answer : 482 ways
a) sizeof($urarray) This function is an alias of count()
b) count($urarray) Questions : 49what is session_set_save_handler in PHP? Answer : 49session_set_save_handler() sets the user-level session storage functions which are used for storing and retrieving data associated with a session. This is most useful when a storage method other than those supplied by PHP sessions is preferred. i.e. Storing the session data in a local database. Questions : 50How can I know that a variable is a number or not using a
JavaScript? Answer : 50bool is_numeric ( mixed var)
Returns TRUE if var is a number or a numeric string, FALSE otherwise.or use isNaN(mixed var)The isNaN() function is used to check if a value is not a number. Questions : 51List out some tools through which we can draw E-R diagrams for
mysql. Answer : 51Case Studio
Smart Draw Questions : 52How can I retrieve values from one database server and store them
in other database server using PHP? Answer : 52we can always fetch from one database and rewrite to another. here
is a nice solution of it.$db1 = mysql_connect("host","user","pwd")
mysql_select_db("db1", $db1);
$res1 = mysql_query("query",$db1);$db2 = mysql_connect("host","user","pwd")
mysql_select_db("db2", $db2);
$res2 = mysql_query("query",$db2);At this point you can only fetch records from you previous ResultSet,
i.e $res1 â€“ But you cannot execute new query in $db1, even if you
supply the link as because the link was overwritten by the new db.so at this point the following script will fail
$res3 = mysql_query("query",$db1); //this will failSo how to solve that? take a look below.
$db1 = mysql_connect("host","user","pwd")
mysql_select_db("db1", $db1);
$res1 = mysql_query("query",$db1);
$db2 = mysql_connect("host","user","pwd", true)
mysql_select_db("db2", $db2);
$res2 = mysql_query("query",$db2);
So mysql_connect has another optional boolean parameter which
indicates whether a link will be created or not. as we connect to the
$db2 with this optional parameter set to 'true', so both link will
remain live.
now the following query will execute successfully.
$res3 = mysql_query("query",$db1); Questions : 53List out the predefined classes in PHP? Answer : 53Directory
stdClass
__PHP_Incomplete_Class
exception
php_user_filter Questions : 54How can I make a script that can be bi-language (supports
English, German)? Answer : 54You can maintain two separate language file for each of the
language. all the labels are putted in both language files as variables
and assign those variables in the PHP source. on runtime choose the
required language option. Questions : 55What are the difference between abstract class and interface? Answer : 55Abstract class: abstract classes are the class where one or more
methods are abstract but not necessarily all method has to be abstract.
Abstract methods are the methods, which are declare in its class but not
define. The definition of those methods must be in its extending class.Interface: Interfaces are one type of class where all the methods are
abstract. That means all the methods only declared but not defined. All
the methods must be define by its implemented class. Questions : 56How can we send mail using JavaScript? Answer : 56JavaScript does not have any networking capabilities as it is
designed to work on client site. As a result we can not send mails using
JavaScript. But we can call the client side mail protocol mailto
via JavaScript to prompt for an email to send. this requires the client
to approve it. Questions : 57How can we repair a MySQL table? Answer : 57The syntex for repairing a MySQL table is
REPAIR TABLENAME, [TABLENAME, ], [Quick],[Extended]
This command will repair the table specified if the quick is given the
MySQL will do a repair of only the index tree if the extended is given
it will create index row by row Questions : 58What are the advantages of stored procedures, triggers, indexes? Answer : 58A stored procedure is a set of SQL commands that can be compiled and
stored in the server. Once this has been done, clients don't need to
keep re-issuing the entire query but can refer to the stored procedure.
This provides better overall performance because the query has to be
parsed only once, and less information needs to be sent between the
server and the client. You can also raise the conceptual level by having
libraries of functions in the server. However, stored procedures of
course do increase the load on the database server system, as more of
the work is done on the server side and less on the client (application)
side.Triggers will also be implemented. A trigger is effectively a type of
stored procedure, one that is invoked when a particular event occurs.
For example, you can install a stored procedure that is triggered each
time a record is deleted from a transaction table and that stored
procedure automatically deletes the corresponding customer from a
customer table when all his transactions are deleted.Indexes are used to find rows with specific column values quickly.
Without an index, MySQL must begin with the first row and then read
through the entire table to find the relevant rows. The larger the
table, the more this costs. If the table has an index for the columns in
question, MySQL can quickly determine the position to seek to in the
middle of the data file without having to look at all the data. If a
table has 1,000 rows, this is at least 100 times faster than reading
sequentially. If you need to access most of the rows, it is faster to
read sequentially, because this minimizes disk seeks. Questions : 59What is the maximum length of a table name, database name, and
fieldname in MySQL? Answer : 59The following table describes the maximum length for each type of
identifier.

Identifier	Maximum Length (bytes)
Database	64
Table	64
Column	64
Index	64
Alias	255

There are some restrictions on the characters that may appear in
identifiers: Questions : 60How many values can the SET function of MySQL take? Answer : 60MySQL set can take zero or more values but at the maximum it can
take 64 values Questions : 61What are the other commands to know the structure of table using
MySQL commands except explain command? Answer : 61describe Table-Name; Questions : 62How many tables will create when we create table, what are they? Answer : 62The '.frm' file stores the table definition.
The data file has a '.MYD' (MYData) extension.
The index file has a '.MYI' (MYIndex) extension, Questions : 63What is the purpose of the following files having extensions 1) .frm
2) .myd 3) .myi? What do these files contain? Answer : 63In MySql, the default table type is MyISAM.
Each MyISAM table is stored on disk in three files. The files have names
that begin with the table name and have an extension to indicate the
file type.
The '.frm' file stores the table definition.
The data file has a '.MYD' (MYData) extension.
The index file has a '.MYI' (MYIndex) extension, Questions : 64What is maximum size of a database in MySQL? Answer : 64If the operating system or filesystem places a limit on the number
of files in a directory, MySQL is bound by that constraint.The efficiency of the operating system in handling large numbers of
files in a directory can place a practical limit on the number of tables
in a database. If the time required to open a file in the directory
increases significantly as the number of files increases, database
performance can be adversely affected.
The amount of available disk space limits the number of tables.
MySQL 3.22 had a 4GB (4 gigabyte) limit on table size. With the MyISAM
storage engine in MySQL 3.23, the maximum table size was increased to
65536 terabytes (2567 â€“ 1 bytes). With this larger allowed table size,
the maximum effective table size for MySQL databases is usually
determined by operating system constraints on file sizes, not by MySQL
internal limits.The InnoDB storage engine maintains InnoDB tables within a tablespace
that can be created from several files. This allows a table to exceed
the maximum individual file size. The tablespace can include raw disk
partitions, which allows extremely large tables. The maximum tablespace
size is 64TB.
The following table lists some examples of operating system file-size
limits. This is only a rough guide and is not intended to be definitive.
For the most up-to-date information, be sure to check the documentation
specific to your operating system.
Operating System File-size LimitLinux 2.2-Intel 32-bit 2GB (LFS: 4GB)
Linux 2.4+ (using ext3 filesystem) 4TB
Solaris 9/10 16TB
NetWare w/NSS filesystem 8TB
Win32 w/ FAT/FAT32 2GB/4GB
Win32 w/ NTFS 2TB (possibly larger)
MacOS X w/ HFS+ 2TB Questions : 65Give the syntax of Grant and Revoke commands? Answer : 65The generic syntax for grant is as following
> GRANT [rights] on [database/s] TO [username@hostname] IDENTIFIED BY
[password]
now rights can be
a) All privileges
b) combination of create, drop, select, insert, update and delete etc.We can grant rights on all databse by using *.* or some specific
database by database.* or a specific table by database.table_name
username@hotsname can be either username@localhost, username@hostname
and username@%
where hostname is any valid hostname and % represents any name, the *.*
any condition
password is simply the password of userThe generic syntax for revoke is as following
> REVOKE [rights] on [database/s] FROM [username@hostname]
now rights can be as explained above
a) All privileges
b) combination of create, drop, select, insert, update and delete etc.
username@hotsname can be either username@localhost, username@hostname
and username@%
where hostname is any valid hostname and % represents any name, the *.*
any condition Questions : 66Explain Normalization concept? Answer : 66The normalization process involves getting our data to conform to
three progressive normal forms, and a higher level of normalization
cannot be achieved until the previous levels have been achieved (there
are actually five normal forms, but the last two are mainly academic and
will not be discussed).First Normal FormThe First Normal Form (or 1NF) involves removal of redundant data
from horizontal rows. We want to ensure that there is no duplication of
data in a given row, and that every column stores the least amount of
information possible (making the field atomic).Second Normal FormWhere the First Normal Form deals with redundancy of data across a
horizontal row, Second Normal Form (or 2NF) deals with redundancy of
data in vertical columns. As stated earlier, the normal forms are
progressive, so to achieve Second Normal Form, your tables must already
be in First Normal Form.Third Normal Form I have a confession to make; I do not often use Third Normal Form. In
Third Normal Form we are looking for data in our tables that is not
fully dependant on the primary key, but dependant on another value in
the table Questions : 67How can we find the number of rows in a table using MySQL? Answer : 67Use this for mysql
>SELECT COUNT(*) FROM table_name; Questions : 68How can we find the number of rows in a result set using PHP? Answer : 68

$result = mysql_query($sql, $db_link);
$num_rows = mysql_num_rows($result);
echo "$num_rows rows found";

Questions : 69How many ways we can we find the current date using MySQL? Answer : 69SELECT CURDATE();
CURRENT_DATE() = CURDATE()
for time use
SELECT CURTIME();
CURRENT_TIME() = CURTIME() Questions : 70What are the advantages and disadvantages of Cascading Style
Sheets? Answer : 70External Style SheetsAdvantagesCan control styles for multiple documents at once. Classes can be
created for use on multiple HTML element types in many documents.
Selector and grouping methods can be used to apply styles under complex
contextsDisadvantagesAn extra download is required to import style information for each
document The rendering of the document may be delayed until the external
style sheet is loaded Becomes slightly unwieldy for small quantities of
style definitionsEmbedded Style Sheets Advantages
Classes can be created for use on multiple tag types in the document.
Selector and grouping methods can be used to apply styles under complex
contexts. No additional downloads necessary to receive style information
Disadvantages
This method can not control styles for multiple documents at once
Inline Styles
Advantages
Useful for small quantities of style definitions. Can override other
style specification methods at the local level so only exceptions need
to be listed in conjunction with other style methods
Disadvantages
Does not distance style information from content (a main goal of
SGML/HTML). Can not control styles for multiple documents at once.
Author can not create or control classes of elements to control multiple
element types within the document. Selector grouping methods can not be
used to create complex element addressing scenarios Questions : 71What type of inheritance that PHP supports? Answer : 71In PHP an extended class is always dependent on a single base class,
that is, multiple inheritance is not supported. Classes are extended
using the keyword 'extends'. Questions : 72What is the difference between Primary Key and
Unique key? Answer : 72Primary Key: A column in a table whose values uniquely identify the
rows in the table. A primary key value cannot be NULL. Unique Key: Unique Keys are used to uniquely identify each row in the
table. There can be one and only one row for each unique key value. So
NULL can be a unique key.There can be only one primary key for a table but there can be more
than one unique for a table.
Question : 73what is garbage collection? default time ? refresh time? Answer : 73Garbage Collection is an automated part of PHP , If the Garbage Collection process runs, it then analyzes any files in the /tmp for any session files that have not been accessed in a certain amount of time and physically deletes them. Garbage Collection process only runs in the default session save directory, which is /tmp. If you opt to save your sessions in a different directory, the Garbage Collection process will ignore it. the Garbage Collection process does not differentiate between which sessions belong to whom when run. This is especially important note on shared web servers. If the process is run, it deletes ALL files that have not been accessed in the directory. There are 3 PHP.ini variables, which deal with the garbage collector: PHP ini value name default session.gc_maxlifetime 1440 seconds or 24 minutes session.gc_probability 1 session.gc_divisor 100 Questions : 74What are the advantages/disadvantages of MySQL and PHP? Answer : 74Both of them are open source software (so free of cost), support
cross platform. php is faster then ASP and JSP. Questions : 75What is the difference between GROUP BY and ORDER BY in Sql? Answer : 75ORDER BY [col1],[col2],â€¦,[coln]; Tels DBMS according to what columns
it should sort the result. If two rows will hawe the same value in col1
it will try to sort them according to col2 and so on.GROUP BY
[col1],[col2],â€¦,[coln]; Tels DBMS to group results with same value of
column col1. You can use COUNT(col1), SUM(col1), AVG(col1) with it, if
you want to count all items in group, sum all values or view average Questions : 76What is the difference between char and varchar data types? Answer : 76Set char to occupy n bytes and it will take n bytes even if u r
storing a value of n-m bytes
Set varchar to occupy n bytes and it will take only the required space
and will not use the n bytes
eg. name char(15) will waste 10 bytes if we store 'romharshan', if each char
takes a byte
eg. name varchar(15) will just use 5 bytes if we store 'romharshan', if each
char takes a byte. rest 10 bytes will be free. Questions : 77What is the functionality of md5 function in PHP? Answer : 77Calculate the md5 hash of a string. The hash is a 32-character
hexadecimal number. I use it to generate keys which I use to identify
users etc. If I add random no techniques to it the md5 generated now
will be totally different for the same string I am using. Questions : 78How can I load data from a text file into a table? Answer : 78you can use LOAD DATA INFILE file_name; syntax to load data
from a text file. but you have to make sure thata) data is delimited
b) columns and data matched correctly Questions : 79How can we know the number of days between two given dates using
MySQL? Answer : 79SELECT DATEDIFF("2007-03-07","2005-01-01"); Questions : 80How can we know the number of days between two given dates using PHP? Answer : 80$date1 = date("Y-m-d");
$date2 = "2006-08-15";
$days = (strtotime($date1) - strtotime($date2)) / (60 * 60 * 24); Questions : 81How we load all classes that placed in different directory in one PHP File , means how to do auto load classes Answer : 81

by using spl_autoload_register('autoloader::funtion');

Like below

class autoloader

{

public static function moduleautoloader($class)

{

$path = $_SERVER['DOCUMENT_ROOT'] . "/modules/{$class}.php";

if (is_readable($path)) require $path;

}

public static function daoautoloader($class)

{

$path = $_SERVER['DOCUMENT_ROOT'] . "/dataobjects/{$class}.php";

if (is_readable($path)) require $path;

}

public static function includesautoloader($class)

{

$path = $_SERVER['DOCUMENT_ROOT'] . "/includes/{$class}.php";

if (is_readable($path)) require $path;

}

}

spl_autoload_register('autoloader::includesautoloader');

spl_autoload_register('autoloader::daoautoloader');

spl_autoload_register('autoloader::moduleautoloader');
Questions : 82How many types of Inheritances used in PHP and how we achieve it Answer : 82As far PHP concern it only support single Inheritance in scripting.
we can also use interface to achieve multiple inheritance. Questions : 83PHP how to know user has read the email? Answers : 83Using Disposition-Notification-To: in mailheader we can get read receipt.
Add the possibility to define a read receipt when sending an email.
Itâ€™s quite straightforward, just edit email.php, and add this at vars definitions:
var $readReceipt = null;
And then, at â€˜createHeaderâ€™ function add:
if (!empty($this->readReceipt)) {
$this->__header .= â€˜Disposition-Notification-To: â€˜ . $this->__formatAddress($this->readReceipt) . $this->_newLine;
} Questions : 84What are default session time and path? Answers : 84default session time in PHP is 1440 seconds or 24 minutes
Default session save path id temporary folder /tmp Questions : 85how to track user logged out or not? when user is idle ? Answers : 85By checking the session variable exist or not while loading th page. As the session will exist longer as till browser closes. The default behaviour for sessions is to keep a session open indefinitely and only to expire a session when the browser is closed. This behaviour can be changed in the php.ini file by altering the line session.cookie_lifetime = 0 to a value in seconds. If you wanted the session to finish in 5 minutes you would set this to session.cookie_lifetime = 300 and restart your httpd server. Questions : 86how to track no of user logged in ? Answers : 86whenever a user logs in track the IP, userID etc..and store it in a DB with a active flag while log out or sesion expire make it inactive. At any time by counting the no: of active records we can get the no: of visitors. Questions : 87in PHP for pdf which library used? Answers : 87The PDF functions in PHP can create PDF files using the PDFlib library With version 6, PDFlib offers an object-oriented API for PHP 5 in addition to the function-oriented API for PHP 4. There is also the Â» Panda module. FPDF is a PHP class which allows to generate PDF files with pure PHP, that is to say without using the PDFlib library. F from FPDF stands for Free: you may use it for any kind of usage and modify it to suit your needs. FPDF requires no extension (except zlib to activate compression and GD for GIF support) and works with PHP4 and PHP5. Questions : 88for image work which library? Answers : 88we will need to compile PHP with the GD library of image functions for this to work. GD and PHP may also require other libraries, depending on which image formats you want to work with. Questions : 89what is design pattern? singleton pattern? Answers : 89A design pattern is a general reusable solution to a commonly occurring problem in software design.
The Singleton design pattern allows many parts of a program to share a single resource without having to work out the details of the sharing themselves. Questions : 90what are magic methods? Answers : 90Magic methods are the members functions that is available to all the instance of class Magic methods always starts with "__". Eg. __construct All magic methods needs to be declared as public To use magic method they should be defined within the class or program scope Various Magic Methods used in PHP 5 are: __construct() __destruct() __set() __get() __call() __toString() __sleep() __wakeup() __isset() __unset() __autoload() __clone() Questions : 91what is magic quotes? Answers : 91Magic Quotes is a process that automagically escapes ncoming data to the PHP script. Itâ€™s preferred to code with magic quotes off and to instead escape the data at runtime, as needed. This feature has been DEPRECATED as of PHP 5.3.0 and REMOVED as of PHP 6.0.0. Relying on this feature is highly discouraged. Questions : 92what is cross site scripting? SQL injection? Answers : 92Cross-site scripting (XSS) is a type of computer security vulnerability typically found in web applications which allow code injection by malicious web users into the web pages viewed by other users. Examples of such code include HTML code and client-side scripts. SQL injection is a code injection technique that exploits a security vulnerability occurring in the database layer of an application. The vulnerability is present when user input is either incorrectly filtered for string literal escape characters embedded in SQL statements or user input is not strongly typed and thereby unexpectedly executed Questions : 93what is URL rewriting? Answers : 93Using URL rewriting we can convert dynamic URl to static URL Static URLs are known to be better than Dynamic URLs because of a number of reasons 1. Static URLs typically Rank better in Search Engines. 2. Search Engines are known to index the content of dynamic pages a lot slower compared to static pages. 3. Static URLs are always more friendlier looking to the End Users. along with this we can use URL rewriting in adding variables [cookies] to the URL to handle the sessions. Questions : 94what is the major php security hole? how to avoid? Answers : 941. Never include, require, or otherwise open a file with a filename based on user input, without thoroughly checking it first.
2. Be careful with eval() Placing user-inputted values into the eval() function can be extremely dangerous. You essentially give the malicious user the ability to execute any command he or she wishes!
3. Be careful when using register_globals = ON It was originally designed to make programming in PHP easier (and that it did), but misuse of it often led to security holes
4. Never run unescaped queries
5. For protected areas, use sessions or validate the login every time.
6. If you donâ€™t want the file contents to be seen, give the file a .php extension. Questions : 95whether PHP supports Microsoft SQL server ? Answers : 95The SQL Server Driver for PHP v1.0 is designed to enable reliable, scalable integration with SQL Server for PHP applications deployed on the Windows platform. The Driver for PHP is a PHP 5 extension that allows the reading and writing of SQL Server data from within PHP scripts. using MSSQL or ODBC modules we can access Microsoft SQL server. Questions : 96what is MVC? why its been used? Answers : 96Model-view-controller (MVC) is an architectural pattern used in software engineering. Successful use of the pattern isolates business logic from user interface considerations, resulting in an application where it is easier to modify either the visual appearance of the application or the underlying business rules without affecting the other. In MVC, the model represents the information (the data) of the application; the view corresponds to elements of the user interface such as text, checkbox items, and so forth; and the controller manages the communication of data and the business rules used to manipulate the data to and from the model. WHY ITS NEEDED IS 1 Modular separation of function 2 Easier to maintain 3 View-Controller separation means:
A â€” Tweaking design (HTML) without altering code B â€” Web design staff can modify UI without understanding code Questions : 97what is framework? how it works? what is advantage? Answers : 97In general, a framework is a real or conceptual structure intended to serve as a support or guide for the building of something that expands the structure into something useful. Advantages : Consistent Programming Model Direct Support for Security Simplified Development Efforts Easy Application Deployment and Maintenance Questions : 98what is CURL? Answers : 98CURL means Client URL Library
curl is a command line tool for transferring files with URL syntax, supporting FTP, FTPS, HTTP, HTTPS, SCP, SFTP, TFTP, TELNET, DICT, LDAP, LDAPS and FILE. curl supports SSL certificates, HTTP POST, HTTP PUT, FTP uploading, HTTP form based upload, proxies, cookies, user+password authentication (Basic, Digest, NTLM, Negotiate, kerberosâ€¦), file transfer resume, proxy tunneling and a busload of other useful tricks.
CURL allows you to connect and communicate to many different types of servers with many different types of protocols. libcurl currently supports the http, https, ftp, gopher, telnet, dict, file, and ldap protocols. libcurl also supports HTTPS certificates, HTTP POST, HTTP PUT, FTP uploading (this can also be done with PHPâ€™s ftp extension), HTTP form based upload, proxies, cookies, and user+password authentication. Questions : 99what is PDO ? Answers : 99The PDO ( PHP Data Objects ) extension defines a lightweight, consistent interface for accessing databases in PHP. if you are using the PDO API, you could switch the database server you used, from say PgSQL to MySQL, and only need to make minor changes to your PHP code.
While PDO has its advantages, such as a clean, simple, portable API but its maindisadvantage is that it doesn't allow you to use all of the advanced features that are available in the latest versions of MySQL server. For example, PDO does not allow you to use MySQL's support for Multiple Statements.
Just need to use below code for connect mysql using PDO
try {
$dbh = new PDO("mysql:host=$hostname;dbname=databasename", $username, $password);
$sql = "SELECT * FROM employee";
foreach ($dbh->query($sql) as $row)
{
print $row['employee_name'] .' - '. $row['employee_age'] ;
}
}
catch(PDOException $e)
{
echo $e->getMessage();
} Questions : 100What is PHP's mysqli Extension? Answers : 100The mysqli extension, or as it is sometimes known, the MySQL improved extension, was developed to take advantage of new features found in MySQL systems versions 4.1.3 and newer. The mysqli extension is included with PHP versions 5 and later.
The mysqli extension has a number of benefits, the key enhancements over the mysql extension being:
=>Object-oriented interface
=>Support for Prepared Statements
=>Support for Multiple Statements
=>Support for Transactions
=>Enhanced debugging capabilities
=>Embedded server support

Versions

-------------

Web developer suite 2.0
Apache server 2.2.6
Php 5.2.5
Mysql 5.0.45

Web application

-----------------

Joomla 1.0.13
Drupal 5.3.0
WordPress 2.3.1
phpBB2 2.0.22

101. what is difference between (short tag) and (full tag).

102. What does a special set of tags do in PHP?

ans- The output is displayed directly to the browser.It works like echo or print function.

103. what is difference between echo and print?

ans- print returns the value in true or false, where as echo doesnot return anything.

104. what is difference between explode implode?

ans-explode function:-it breaks a string into array.
$str="hello world.it's a beautiful day.":
print_r(explode(" ",$str):// space between two double quotes should be there otherwise it shows Warning: explode() [function.explode]: Empty delimiter in D:\www\vhosts\localhost\test\setupTest.php on line 29
?>
ans-ARRAY
[0]=>hello
[1]=>world.
[2]=>it's
[3]=>a
[4]=>beautiful
[5]=>day.

implode:-returns a string from elements of an array.
$arr=array('hello','world!',beautiful,'day!');
echo implode(" ",$arr);
?>
ans-hello world! beautiful day!

105.Will comparison of string "10" and integer 11 work in PHP?

ans-Yes, internally PHP will cast everything to the integer type, so numbers 10 and 11 will be compared.

106. how many types array are there in php?

ans- There are two types of array- a) numerical or index array b) associative array
In numerical or index array the indexer,which is used to determine the position of a stored data (also known as key) is an integer.

Where as in case of associative array the indexer or key which is used to reffered the data element is a string.

107. what is terinary opertion in php?

ans- It is called the ternary operator because it takes three operands - a condition, a result for true, and a result for false.

                   OR

Expression preceding the ? is evaluated, if it’s true, then the expression preceding   the : is executed, otherwise, the expression following : is executed.

               $agestr = ($age < 18) ? 'child' : 'adult';
    ?>

108. explain two types of arraay sort.

ans-sort()->sort the array value alphabetically, but not maintaining the index.
    asort()->sort the array value alphabetically, and also maintaining the index.
    arsort()->sort the array value alphabetically in reverse order and also maintaining the index.

    ksort()->sort the array according to key.
    krsort()->sort the array according to key in the reverse order.

109. what is difference between strstr and stristr?

strstr-finds the first occurence of a string inside another
string (case-sensitive)
examle: $email = 'arvindpippal@gmail.com';
$domain = strstr($email, '@');
echo $domain;
?>
output: @gmail.com

stristr-finds the first occurence of a string inside
another string (case-insensitive)

110.what is substr()?

ans-substr() returns the portion of string specified by the start and length parameters.
syntax:- string substr ( string string, int start [, int length] )

111.Can u change localhost name in ur localsystem?

ans- yes, inside
C:\Windows\System32\drivers\etc\hosts

112.how can u know size of array?

ans-The sizeof() function counts the elements of an array, or the properties of an object.

This function is an alias of the count() function.
$a = array(1,2,2,
    array(1,1));
    echo sizeof($a);// 4
    echo sizeof($a[1]);// 1
        echo sizeof($a[3]);// 2

113.Number of argument in a function,How can u know?

ans-func_num_args() function returns the number of parameters passed in.

114.what is a session and how can u destroy it?

ans-A PHP session allowing you to store user information on the server for later use (i.e. username, shopping items, etc). However, session information is temporary and will be deleted after the user has left the website. If you need a permanent storage you may want to store the data in a database.

we are using session_unset()(deprecated) or session_destroy() to destroy the session. session_unset() free the all session variables,but session continues whereas session_destroy() destroys the session.

115.what is a cookies and how can u destroy it?

ans-. A cookie is a small file that the server embeds on the user's computer. Each time the same computer requests a page with a browser, it will send the cookie too.

    The setcookie() function is used to set a cookie.
        $expire=time()+60*60*24*30;
    setcookie("user", "Alex Porter", $expire);
    ?>

The PHP $_COOKIE variable is used to retrieve a cookie value.

        // Print a cookie
    echo $_COOKIE["user"];

    // A way to view all cookies
    print_r($_COOKIE);
    ?>
When deleting a cookie you should assure that the expiration date is in the past.
        // set the expiration date to one hour ago
    setcookie("user", "", time()-3600);
    ?>

116. how can u get current date and time?

ans- date('r');

117. how can u upload a image?

ans- we can upload a file by using the function move_uploaded_method() function.
18. what is difference between get and post?

ans-GET:- get method is default method.
    un secure way as data send through the url.
    we can send limited amount of data as url supports 255 characters.

    POST:- not a default method, we have to mention it explicitly.
    its a secure way as data send through the body part.
    we can send unlimited amount of data.

119. How can u et ip address of asystem?

ans- $_SERVER['SERVER_ADDR'];

$_SERVER['REMOTE_ADDR'];

120. What is magic function and what are they?

121. What is Isset()?

ans-isset() determines whether a certain variable has already been declared by PHP. It returns a boolean value true if the variable has already been set, and false otherwise, or if the variable is set to the value NULL.

122. How can you submit a form without using submit buttom?

ans-Using javascript we can submit a form without using submmit button.

OR

If you don’t want to use the Submit button to submit a form, you can use normal hyper links to submit a form. But you need to use some JavaScript code in the URL of the link. For example:

Submit Me

123. what is difference between require() and require_once()?

ans-require() includes and evaluates a specific file while require_once() does that only if it has not been included before (on the same page).

124. what is difference between include() and include_once()?

ans-include() includes and evaluates a specific file while include_once() does that only if it has not been included before (on the same page).

125. what is difference between include() and require()?

ans- It’s how they handle failures. If the file is not found by require(), it will cause a fatal error and halt the execution of the script. If the file is not found by include(), a warning will be issued, but execution will continue.

126. What is the difference between ereg_replace() and eregi_replace()?

ans-eregi_replace() function is identical to ereg_replace() except that it ignores case distinction when matching alphabetic characters.

127. what is oops?

ans-One of the main advantages of OO programming is its ease of modification; objects can easily be modified and added to a system there by reducing maintenance costs. OO programming is also considered to be better at modeling the real world than is procedural programming. It allows for more complicated and flexible interactions. OO systems are also easier for non-technical personnel to understand and easier for them to participate in the maintenance and enhancement of a system because it appeals to natural human cognition patterns. For some systems, an OO approach can speed development time since many objects are standard across systems and can be reused. Components that manage dates, shipping, shopping carts, etc. can be purchased and easily modified for a specific system.

128. What in inheritance and how many types of inheritance are there in php?

129. What in methodoverloading and polymerphism?

130. What is methodoverriding?

131. What is method overloading and over riding?

132. What is Php encapsulation?

133. What is abstarct method and abstarct class?

134. What is final method and final class?

135. What is Super concepts?

136. What is constructor and destructor?

137. what are the access specifier?

ans-The visibility of a property or method can be defined by prefixing the declaration with the keywords public, protected or private. Class members declared public can be accessed everywhere. Members declared protected can be accessed only within the class itself and by inherited and parent classes. Members declared as private may only be accessed by the class that defines the member.

138. What is 'This' key word?

139. what is coersion?

140. What is interface?

141. What is Exception handling?

142. waht is wrapper calss?

143. Give an example of Foreach;

144. what is split();?

ans- split is a function used for split the string by regular expression.

split(":",$string);

145. What is abstraction in php?

146. function to display money separator by comma?

147. How can we send mail using JavaScript?

ans-No. There is no way to send emails directly using JavaScript.

But you can use JavaScript to execute a client side email program send the email using the “mailto” code. Here is an example:

{xtypo_code}
function myfunction(form)
{
   tdata=document.myform.tbox1.value;
   location=”mailto: mailid@domain.com?subject=…”;
   return true;
}
{/xtypo_code}

148.What is the difference between the functions unlink and unset?

ans-unlink() is a function for file system handling. It will simply delete the file in context.

unset() is a function for variable management. It will make a variable undefined.

149. what is difference between split() and explode()?

ans- split()-split the string by regular expression.
    split(":",$string);
     explode()-split the string by string.
    explode("",$string);

150. How can you get browser informaion in php?

151. what is difference between sinle qoute and double qoute?

152. what is role of == and === ,when we compare array?

153. what is CURL and its functionality?

154. what is MIME?

ans-MIME is Multipurpose Internet Mail Extensions is an Internet standard for the format of e-mail. However browsers also uses MIME standard to transmit files. MIME has a header which is added to a beginning of the data. When browser sees such header it shows the data as it would be a file (for example image)

Some examples of MIME types:

audio/x-ms-wmp
image/png
aplication/x-shockwave-flash

OR

Multipurpose Internet Mail Extensions.
WWW’s ability to recognize and handle files of different types is largely dependent on the use of the MIME (Multipurpose Internet Mail Extensions) standard. The standard provides for a system of registration of file types with information about the applications needed to process them. This information is incorporated into Web server and browser software, and enables the automatic recognition and display of registered file types. …

155. what is difference between drop table and truncate table?

ans-DROP TABLE table_name – This will delete the table and its data.

TRUNCATE TABLE table_name – This will delete the data of the table, but not the table definition.

156. what is difference between unset and unlink?

157. what is difference between __sleep and __wakeup()?

ans-- __sleep returns the array of all the variables than need to be saved, while __wakeup retrieves them.

158. what is difference between htmlenties and htmlspecialcharacter()?

ans- htmlspecialchars only takes care of <, >, single quote ‘, double quote ” and ampersand. htmlentities translates all occurrences of character sequences that have different meaning in HTML.

159. Whar are the errors in php?

ans-Here are three basic types of runtime errors in PHP:

1. Notices: These are trivial, non-critical errors that PHP encounters while executing a script – for example, accessing a variable that has not yet been defined. By default, such errors are not displayed to the user at all – although you can change this default behavior.

2. Warnings: These are more serious errors – for example, attempting to include() a file which does not exist. By default, these errors are displayed to the user, but they do not result in script termination.

3. Fatal errors: These are critical errors – for example, instantiating an object of a non-existent class, or calling a non-existent function. These errors cause the immediate termination of the script, and PHP’s default behavior is to display them to the user when they take place.

Internally, these variations are represented by twelve different error types

160. Is object of a class pass by a refference?

ans- Everything is passed by value.

161. What are the differences between mysql_fetch_array(), mysql_fetch_object(), mysql_fetch_row()?

ans-mysql_fetch_array – Fetch a result row as an associative array and a numeric array.

mysql_fetch_object – Returns an object with properties that correspond to the fetched row and moves the internal data pointer ahead. Returns an object with properties that correspond to the fetched row, or FALSE if there are no more rows

mysql_fetch_row() – Fetches one row of data from the result associated with the specified result identifier. The row is returned as an array. Each result column is stored in an array offset, starting at offset 0.

162. How can you know value of a current session id?

ans-session_id();

163. How can you find difference between two dates?

164. how can u encrypt user name or passwors in php?

ans-using md5() we can encrypt username or password field in php.

165. How many way you can get a date from mysql?

ans-SELECT CURDATE();
SELECT CURRENT_DATE();
SELECT CURTIME();
SELECT CURRENT_TIME();

166. what is mysql engines and what are they?

167. what is difference between myisam and innodb?

168. what are the joins in mysql and what are they?

ans-Different types of joins are ----

    1.JOIN(Inner Join): Return rows when there is at least one match in both tables
    2.LEFT JOIN: Return all rows from the left table, even if there are no matches in the right table
    3.RIGHT JOIN: Return all rows from the right table, even if there are no matches in the left table
    4.FULL JOIN: Return rows when there is a match in one of the tables

169. what is normalisation ?

ans-The normalization process involves getting our data to conform to three progressive normal forms, and a higher level of normalization cannot be achieved until the previous levels have been achieved (there are actually five normal forms, but the last two are mainly academic and will not be discussed).

First Normal Form
The First Normal Form (or 1NF) involves removal of redundant data from horizontal rows. We want to ensure that there is no duplication of data in a given row, and that every column stores the least amount of information possible (making the field atomic).

Second Normal Form
Where the First Normal Form deals with redundancy of data across a horizontal row, Second Normal Form (or 2NF) deals with redundancy of data in vertical columns. As stated earlier, the normal forms are progressive, so to achieve Second Normal Form, your tables must already be in First Normal Form.

Third Normal Form

I have a confession to make; I do not often use Third Normal Form. In Third Normal Form we are looking for data in our tables that is not fully dependant on the primary key, but dependant on another value in the table

170. What is the maximum length of a table name, a database name, or a field name in MySQL?

ans- Database name: 64 characters
Table name: 64 characters
Column name: 64 characters

171. list of php CMS?

ans - Drupal, Joomla, PhpBB, Wordpress.

172. list of frameworks in php ?

ans- Zend,CodeIgniter and CackePHP framework.

173. Difference between CMS and Framework.

ans-An application framework is something which we use to build our web application on, I mean we use the framework provided classes, events, methods and create an application.

A CMS is already a developed application with a set of features, however most of them are coded in such a way that users can tweak them around and modify the code to fit their own needs.

So a framework does not come with a working application, but a CMS comes with one.

174. Http default port no.?

ans- 80

175. Http is stateless or stateful?

ans- stateless.

176. How to unset coockie?

ans- by setting the set cookie method in back date.

    setcookie(name,value,expire,path,domain,secure)
    setcookie("TestCookie",$value, time()+3600*24);
    setcookie ("TestCookie", "", time() - 3600);

177. what is the output ?

           $param = "value";
       $value = 10;
       print ${$param};// 10
       print $$param;// 10
       print '$$param';// $$param
    ?>

178. What is the function to upload a file?

ans - move_uploaded_file();

179. Max execution time?

ans- 30sec.

180. Max uploading size?

ans- 2Mb

181. How session starts?

ans- session_start()
82.What is ob_start()?

ans-ob_start() function turn on the output buffering, while output buffering is active no output is sent from the script, other than header.

183. how to run php file from command prompt?

184. Difference between session and cookie?

185. What is stored procedure?

186. What is the use of === ?

187. Use of static keyword?

ans-Declaring class properties or methods as static makes them accessible without needing an instantiation of the class.

188. Types of file format under mysql5->data folder?

ans- There are three types of file format
    1.frm
    2.MYD
    3.MYI

189. What are the new features added in PHP5 ?

ans- Addition features of PHP5-----
    1.Visibility
    2.Abstract
    3.Final
    4.Methods
    5.Class
    6.Magic methods or functions
    7.Interface
    8.Cloning
    9.Typehinting

190. What is AJAX ?

ans-AJAX = Asynchronous JavaScript and XML.

AJAX is a technique for creating fast and dynamic web pages.

AJAX allows web pages to be updated asynchronously by exchanging small amounts of data with the server behind the scenes. This means that it is possible to update parts of a web page, without reloading the whole page.

AJAX applications are browser- and platform-independent!

All modern browsers support the XMLHttpRequest object (IE5 and IE6 uses an ActiveXObject).

The XMLHttpRequest object is used to exchange data with a server behind the scenes. This means that it is possible to update parts of a web page, without reloading the whole page.

var xmlhttp;
if (window.XMLHttpRequest)
{// code for IE7+, Firefox, Chrome, Opera, Safari
xmlhttp=new XMLHttpRequest();
}
else
{// code for IE6, IE5
xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}

To handle all modern browsers, including IE5 and IE6, check if the browser supports the XMLHttpRequest object. If it does, create an XMLHttpRequest object, if not, create an ActiveXObject

To send a request to a server, we use the open() and send() methods of the XMLHttpRequest object:

xmlhttp.open("GET","ajax_info.txt",true);
xmlhttp.send();

GET is simpler and faster than POST, and can be used in most cases.

However, always use POST requests when:

    * A cached file is not an option (update a file or database on the server)
    * Sending a large amount of data to the server (POST has no size limitations)
    * Sending user input (which can contain unknown characters), POST is more robust and secure than GET

If you want to send information with the GET method, add the information to the URL:

xmlhttp.open("GET","demo_get2.asp?fname=Henry&lname=Ford",true);
xmlhttp.send();

To POST data like an HTML form, add an HTTP header with setRequestHeader(). Specify the data you want to send in the send() method:

xmlhttp.open("POST","ajax_test.asp",true);
xmlhttp.setRequestHeader("Content-type","application/x-www-form-urlencoded");
xmlhttp.send("fname=Henry&lname=Ford");

setRequestHeader(header,value) ->Adds HTTP headers to the request.

header: specifies the header name
value: specifies the header value

AJAX stands for Asynchronous JavaScript and XML, and for the XMLHttpRequest object to behave as AJAX, the async parameter of the open() method has to be set to true:

xmlhttp.open("GET","ajax_test.asp",true);

Sending asynchronously requests is a huge improvement for web developers. Many of the tasks performed on the server are very time consuming. Before AJAX, this operation could cause the application to hang or stop.

With AJAX, the JavaScript does not have to wait for the server response, but can instead:

    * execute other scripts while waiting for server response
    * deal with the response when the response ready

Async=true

When using async=true, specify a function to execute when the response is ready in the onreadystatechange event:

xmlhttp.onreadystatechange=function()
{
if (xmlhttp.readyState==4 && xmlhttp.status==200)
    {
    document.getElementById("myDiv").innerHTML=xmlhttp.responseText;
    }
}
xmlhttp.open("GET","ajax_info.txt",true);
xmlhttp.send();

Async=false

To use async=false, change the third parameter in the open() method to false:

Using async=false is not recommended, but for a few small requests this can be ok.

Remember that the JavaScript will NOT continue to execute, until the server response is ready. If the server is busy or slow, the application will hang or stop.

Note: When you use async=false, do NOT write an onreadystatechange function - just put the code after the send() statement:

xmlhttp.open("GET","ajax_info.txt",false);
xmlhttp.send();
document.getElementById("myDiv").innerHTML=xmlhttp.responseText;

The onreadystatechange event
-------------------------------

When a request to a server is sent, we want to perform some actions based on the response.

The onreadystatechange event is triggered every time the readyState changes.

The readyState property holds the status of the XMLHttpRequest.

Three important properties of the XMLHttpRequest object:

In the onreadystatechange event, we specify what will happen when the server response is ready to be processed.

When readyState is 4 and status is 200, the response is ready:

xmlhttp.onreadystatechange=function()
{
if (xmlhttp.readyState==4 && xmlhttp.status==200)
    {
    document.getElementById("myDiv").innerHTML=xmlhttp.responseText;
    }
}

if (window.XMLHttpRequest)
{// code for IE7+, Firefox, Chrome, Opera, Safari
xmlhttp=new XMLHttpRequest();
}
else
{// code for IE6, IE5
xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.onreadystatechange=function()
{
if (xmlhttp.readyState==4 && xmlhttp.status==200)
    {
    document.getElementById("txtHint").innerHTML=xmlhttp.responseText;
    }
}
xmlhttp.open("GET","gethint.php?q="+str,true);
xmlhttp.send();

91. What is main strength of Ajax ?

ans- AJAX does not refresh or reload the whole page as because Ajax uses asynchronous technology.
In a word, a program does not wait for response after requesting an asynchronous call whereas synchronous does so.

192. How session works?

ans- Nearly every PHP application uses sessions. This article takes a detailed look at implementing a secure session management mechanism with PHP. Following a fundamental introduction to HTTP, the challenge of maintaining state, and the basic operation of cookies, I will step through simple and effective methods that can be used to increase the security and reliability of your stateful PHP applications.

It is a common misconception that PHP provides a certain level of security with its native session management features. On the contrary, PHP simply provides a convenient mechanism. It is up to the developer to provide the complete solution, and as you will see, there is no one solution that is best for everyone.

Statelessness
HTTP is a stateless protocol. This is because there is nothing within the protocol that requires the browser to identify itself during each request, and there is also no established connection between the browser and the web server that persists from one page to the next. When a user visits a web site, the user's browser sends an HTTP request to the web server, which in turn sends an HTTP response in reply. This is the extent of the communication, and it represents a complete HTTP transaction.

Because the web relies on HTTP for communication, maintaining state in a web application can be particularly challenging for developers. Cookies are an extension of HTTP that were introduced to help provide stateful HTTP transactions, but privacy concerns have prompted many users to disable support for cookies. State information can be passed in the URL, but accidental disclosure of this information poses serious security risks. In fact, the very nature of maintaining state requires that the client identify itself, yet the security-conscious among us know that we should never trust information sent by the client.

Despite all of this, there are elegant solutions to the problem of maintaining state. There is no perfect solution, of course, nor is there one solution that can satisfy everyone's needs. This article introduces some techniques that can reliably provide statefulness as well as defend against session-based attacks such as session hijacking. Along the way, you will learn how cookies really work, what PHP sessions do, and what is required to hijack a session.

193.What is interface?

ans- PHP does not support multiple inheritance directly, to implement this we need Interface. It is much similar to Interface of Java.

In PHP, signature of the method are declared in the Interface body, and the body part of the method is implemented in derived class. Variables are declared as constant and it can not be changed in the child classes.

We use implement keyword to extend this kind of class, at the same time we can implement more than one interface and one interface can be implemented by another interface.

All methods declared in an interface must be public and the variables should be constant.

This is mandatory that we must declare the body part of the method in the derived class otherwise an error message will be generated.

Example:

interface Inter{

const a="This is constant value";

public function disp(); }

class A implements Inter{

function show(){

echo self::a."
";}

public function disp(){

echo "Inside the disp function";}}

$a=new A();

$a->show();

$a->disp();

?>

Output:

This is constant value
Inside the disp function

194. Difference between Http and Ftp ?

ans- 1
FTP stands for File Transfer Protocol.
HTTP stands for Hyper Text Transfer Protocol
2
FTP, is a protocol used to upload files from a workstation to a FTP server or download files from a FTP server to a workstation.
HTTP, is a protocol used to transfer files from a Web server onto a browser in order to view a Web page that is on the Internet.
3
When ftp appears in a URL it means that the user is connecting to a file server and not a Web server and that some form of file transfer is going to take place.
When http appears in a URL it means that the user is connecting to a Web server and not a file server. The files are transferred but not downloaded, therefore not copied into the memory of the receiving device.
4
FTP is a two-way system as files are transferred back and forth between server and workstation.
HTTP is a one-way system as files are transported only from the server onto the workstation's browser.
5
FTP, where entire files are transferred from one device to another and copied into memory,
HTTP only transfers the contents of a web page into a browser for viewing.
6
FTP file uploaded is used in cases when the file size is more than 70 MB
HTTP upload is used for smaller files.
7
FTP uses an FTP client server and an FTP client.
HTTP is used for all web [ages i.e. it is the standard protocol to transmit hyperlinked documents and files. It is often used in conjunction with HTML.
8
FTP was the original non-GUI file transfer program and could be run from a command line interface like MS-DOS.
HTTP is associated with a browser file transfer program like Internet Explorer.

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Perl Regular Expressions

noreply@blogger.com (Anonymous) — Mon, 27 Sep 2010 03:19:00 -0700

Regular expression to match only for any type of symbols.

I'm going to write a simple regex that will validate whether the provided string contains only symbols or not. No alphabet or numbers or spaces are allowed. Giving the expression using Perl, but it will work with any programming language as long as it PCRE.

my $str = "^%^";
if( $str =~ /^[!-\/:-@\[-`\{-~]+$/ ){
print "String contains only symbols.\n";
}

So the actual regex is ^[!-\/:-@\[-`\{-~]+$
Posted by Demon at 1:07 AM 0 comments Links to this post
Labels: perl, php
Thursday, December 3, 2009
Regular expression to validate clock time

To validate time from 00:00 to 11:59 you can use a simple regex.

The regex is (?:0[0-9]|1[0-1]):[0-5][0-9]
It means if the first digit of hour is 0, then second digit can be any one from 0-9.
Otherwise if the first digit is 1, that case second digit can only be 1 or 2.

For minute section, first digit can be only from 0-5, and second digit can be from 0-9.

I'm giving you the example using a perl code, but the regex will work with any PCRE compatible engine.

Using Perl

my $time = "01:19";
if($time =~ /(?:0[0-9]|1[0-1]):[0-5][0-9]/){
print "the time is valid\n";
}
else{
print "the time is not valid\n";
}

Simple task, but yet too hard if you don't this :-)
Posted by Demon at 11:25 AM 1 comments Links to this post
Labels: perl, php
Friday, November 13, 2009
Perl: What is the equivalent of Ceil()

Question: At Perl, what is the equivalent function of Ceil? Or how can I perform Ceil on a number like other languages.

Answer: So far, I don't know any function to serve this issue. But if I need, I use sprintf() combined with floating. Below example will show you what exactly I mean for.

my $number = 10.51;
$number = sprintf("%.0f", $number);
print $number;

The above code will output 11, which is the exact ceiling of 10.51.
Posted by Demon at 7:23 AM 2 comments Links to this post
Labels: perl
Perl: What is the equivalent to floor()

Question: What is the equivalent of function floor() at Perl?

Answer: Simple answer is to use int() function. This will just remove the decimal portion from the provided number. Example code using int() to serve like floor is,

print int(10.9);

Posted by Demon at 7:18 AM 0 comments Links to this post
Labels: perl
Wednesday, August 5, 2009
Sql Injection and how to prevent this.

Its one of the dangerous hole to your site which will allow any unwanted guest access your database or control panel. Last few weeks I was working with SQL injecting, and found lots of websites from the worldwide which are welcoming the hackers to use their unknown hole of website.

I'm not that much expert on website coding. You can say I don't work with database. So I don't know much about this stuff. But one thing I learned is, just validate every singe GET or POST parameter from your website script.

Don't trust anyone. Just validate, and check whether its having the format you need or not. If you don't know how to validate your GET/POST parameters, not to worry. Just replace any single quote(') with anything. Don't let this shit to pass.

Or you can use adding slashes types of function depending upon language, to get rid of it. At least it will save your ass for few. But there might be many other ways to find hole. I only know single quoting.

Once again, try to go for validation, even for numbers.
Posted by Demon at 12:23 PM 0 comments Links to this post
Labels: C/C++, java, javascript, perl, php, python, ruby
Perl: Swap string value using s///

This a funny way to swap two values from a string using perl's s///. This will only work if the two words contain exactly one times inside string. I was just wondering about it, and think to add here for all.

Let say you have a string, and you want to swap the words "demo" and "test" with each other. So the simple code will be as below.

## initial string to swap
my $string = "test string and demo string";
## swaping test with demo
$string =~ s/(test)(.*?)(demo)/$3$2$1/;
print "$string\n";

Inside the regex you'll need to change the position of test and demo depending upon the position from original string. And remember this will work only if both string exist only once. For multiple I didn't check, So don't know.

Once again, its a funny stuff, but may come helpful for somebody. Don't forget to add a comment if anyone find such.
Posted by Demon at 11:10 AM 0 comments Links to this post
Labels: perl
Sunday, August 2, 2009
Perl: Various ways to read a file

There is only one way to open or close a file usine open() close() function. You'll find lots of cpan modules which will help you to read file, but internally all the modules are using these to functions to open and close files. I'm showing you how can you read a file into array, or string, or anything else. Just few coding helps regarding file operation.

1) Read the whole file content into an array directly.

open(INFILE, "my @lines = ; ## read into array
close(INFILE); ## close handler

This code will read all the contents from input.txt, and will load into array @lines directly. Later on, you can do whatever operation you need. You have the file on your hand.

2) Read a single line from your input file.

open(INFILE, "my $line = ; ## read a single line
close(INFILE); ## close handler

Perl interpreter is intelligent enough to understand your need. Since you provided a scalar to file handler, it will return you the current line that the file handler pointing. This case it will return you only the first line.

3) Using a loop, say while(), process each line while reading without using any array.

open(INFILE, "while(){
# current line at the variable $_
## process here
}
close(INFILE); ## close handler

If you don't want to use the default $_ variable, that case you can use this loop.

while (my $line = ){
print $line;
}

4) Read the whole file content into a string instead of array. I used to use join() function to do this.

open(INFILE, "my $file_content = join('', );
close(INFILE); ## close handler

This join function just take the whole file as array, and join each line from the array. A bit tricky, but nothing else.

I think this will cover what you need when you'll do some file operation at perl scripting.
Posted by Demon at 12:35 AM 0 comments Links to this post
Labels: perl
Friday, July 24, 2009
Perl: Explanation of your regular expression

Perl CPAN has a module called "YAPE::Regex::Explain" which will help you to understand what is a perl regular expression doing.

Lets say you have a Regex [Za-z0-9]+ Here is the sample code if you want to get the explanation of your regex.

use YAPE::Regex::Explain;
print YAPE::Regex::Explain->new('[A-Za-z0-9]+')->explain;

This simple code will output as below on your screen, and which is easily understandable to get what is going on.

The regular expression:

(?-imsx:[A-Za-z0-9]+)

matches as follows:

NODE EXPLANATION
----------------------------------------------------------------------
(?-imsx: group, but do not capture (case-sensitive)
(with ^ and $ matching normally) (with . not
matching \n) (matching whitespace and #
normally):
----------------------------------------------------------------------
[A-Za-z0-9]+ any character of: 'A' to 'Z', 'a' to 'z',
'0' to '9' (1 or more times (matching the
most amount possible))
----------------------------------------------------------------------
) end of grouping
----------------------------------------------------------------------

Lets try with a bit complex regular expression ST[^;]*(?:[A-Za-z0-9]+|[\.,\s]+)ET

The code for explaining for REGEX will be,

use YAPE::Regex::Explain;
print YAPE::Regex::Explain->new('ST[^;]*(?:[A-Za-z0-9]+|[\.,\s]+)ET')->explain;

Output is as below, and which is damn understandable.

The regular expression:

(?-imsx:ST[^;]*(?:[A-Za-z0-9]+|[\.,\s]+)ET)

matches as follows:

NODE EXPLANATION
----------------------------------------------------------------------
(?-imsx: group, but do not capture (case-sensitive)
(with ^ and $ matching normally) (with . not
matching \n) (matching whitespace and #
normally):
----------------------------------------------------------------------
ST 'ST'
----------------------------------------------------------------------
[^;]* any character except: ';' (0 or more times
(matching the most amount possible))
----------------------------------------------------------------------
(?: group, but do not capture:
----------------------------------------------------------------------
[A-Za-z0-9]+ any character of: 'A' to 'Z', 'a' to
'z', '0' to '9' (1 or more times
(matching the most amount possible))
----------------------------------------------------------------------
| OR
----------------------------------------------------------------------
[\.,\s]+ any character of: '\.', ',', whitespace
(\n, \r, \t, \f, and " ") (1 or more
times (matching the most amount
possible))
----------------------------------------------------------------------
) end of grouping
----------------------------------------------------------------------
ET 'ET'
----------------------------------------------------------------------
) end of grouping
----------------------------------------------------------------------

Running the code from Command Line:

If you don't like to write a code for this, you can do it from your command line. Just one liner perl script. For above expression the code will be as below.

perl -MYAPE::Regex::Explain -e "print YAPE::Regex::Explain->new('ST[^;]*(?:[A-Za-z0-9]+|[\.,\s]+)ET')->explain;"

How to install the module:

To install the module from your command prompt,
ppm install YAPE::Regex::Explain

And then type
ppm install YAPE::Regex

This installation can be done using cpan too.
Posted by Demon at 6:39 AM 2 comments Links to this post
Labels: perl
Friday, July 10, 2009
Perl: Http::Cookies not saving cookie correctly

The below code for saving the http cookie after requesting some data over http is not working!!! Did you face this kind of problem anyway?

$cookie_jar->save()

For example the server sent you 4 cookies. But your cookie_jar is only saving the 2 of them, and rest of the two are ignored. Do you know the reason behind this?

It's not a bug of http cookies of perl, or lwp. Just lack of knowing the issue. Initially I thought it was a bug. The rest of the two cookies are session cookie. And it will die when you'll close your browser( this case your LWP ). That's why Http::Cookies is not saving the cookie on your file. Here is what it was said on the docs of HTTP::Cookies,

$cookie_jar->save
$cookie_jar->save( $file )

This method file saves the state of the $cookie_jar to a file. The state can then be restored later using the load() method. If a filename is not specified we will use the name specified during construction. If the attribute ignore_discard is set, then we will even save cookies that are marked to be discarded.

The default is to save a sequence of "Set-Cookie3" lines. "Set-Cookie3" is a proprietary LWP format, not known to be compatible with any browser. The HTTP::Cookies::Netscape sub-class can be used to save in a format compatible with Netscape.

HTTP::Cookies

So, this means you have to notify the cookie_jar to save your session cookie too. To do this you have to do as below.

$cookie_jar = HTTP::Cookies->new(
file => "cookie.txt",
ignore_discard => 1,
);

$cookie_jar = HTTP::Cookies->new(
ignore_discard => 1,
);

Posted by Demon at 11:38 PM 2 comments Links to this post
Labels: perl
Saturday, June 27, 2009
Perl: Left padding an integer using sprintf

Using the function sprintf() of Perl, you can easily left pad any given integer number easily. The sprintf() function is similar to use like other programming languages. I'm giving an example of showing a given integer number with 5 field, where left sides will filled with zeros if any.

my $integer = 10;
$integer = sprintf("%05d", $integer);
print "$integer\n";

Just a simple left padding.
Posted by Demon at 10:05 AM 0 comments Links to this post
Labels: perl
Thursday, June 18, 2009
Perl: how to get position of a certain character in a string

There is a function called strpos() at php for this, and if you are looking for the similar function support at perl, then you have index() at Perl.

The index() function takes string and search string as parameter. Here is the example code.

$string = "tester of the world";
$search_string = "r";
print index($string, $search_string);

This will output 5, as 5 is the first occurrence or search string from the provided string. You can use character, or string as search. And remember the index starts from 0. At above example r is at the 5th index.
Posted by Demon at 12:00 PM 0 comments Links to this post
Labels: perl
Tuesday, June 9, 2009
Perl Number formating using Regexp

Using a single regex you can easily convert a number like 1234567890 into 1,234,567,890. I don't what this call, that's why I was put the title is number formatting. Here goes the regular expression with example.

my $number = 1234567890;
$number =~ s/(\d)(?=(\d{3})+(\D|$))/$1\,/g;
print $number;

Output : 1,234,567,890

The above regex just takes the digits from last, or three digits just before the comma, and if another extra digit exist without those three, it just push a comma inside. This will make one digit goes to left side, and other three digits goes to right side.

Just a simple regexp made your life easier to do such kind of conversion.
Posted by Demon at 10:59 AM 0 comments Links to this post
Labels: perl
Sunday, May 31, 2009
Remove the words having special characters from a string

Lets learn how to remove the words from a string which contains the special characters. I mean the word having non-English characters. Consider the below example.
asdasd óadsa, xxxÂr 123, asda koskso øppp iø1 asdakjd*ads8

You can see several words from the above contains special/non-english character on them. I'll write a regex that will remove those kind of words from the sentence above.

A PHP code:

$string = "asdasd óadsa, xxxÂr 123, asda koskso øppp iø1 asdakjd*ads8";
$string = preg_replace('/\S*[^a-z0-9A-Z\s,\.]+\S*/', '', $string);
print "$string\n";

Output: asdasd 123, asda koskso

A Perl code:

$string = "asdasd óadsa, xxxÂr 123, asda koskso øppp iø1 asdakjd*ads8";
$string =~ s/\S*[^a-z0-9A-Z\s,\.]+\S*//g;
print "$string\n";

Output: asdasd 123, asda koskso

You can use trim on the string, or replace multiple spaces with single one after that. Also you can add other characters like dot, comma inside the regex to distinguish the word.

Cheers!!!
Posted by Demon at 9:24 AM 1 comments Links to this post
Labels: perl, php
Saturday, May 30, 2009
Conditional Log filtering for your apache

At my website I found that there were lots of log entry at my access_log for GIF images. I wanted to find a way so that there will be no entry at my access_log for GIF images. I found the way, and here is how you need to filter your log entry for GIF images.

SetEnvIf Request_URI \.GIF$ no-log
CustomLog log/access.log combined env =! no-log

This will help you to prevent writing any entry at your log file. If you want to add more file types at your filtering condition, you can use them using pipe(|). For example below.

SetEnvIf Request_URI "\.(PNG|png|gif|GIF)$" no-log
CustomLog log/access.log combined env =! no-log

But for anything, make sure that you have setenvif module is loaded. To check this you can use either httpd -M or apache2 -M depending upon your system.

Hope this little information will help you to setup custom logging for your apache.
Posted by Demon at 7:26 AM 0 comments Links to this post
Labels: perl, php
Thursday, May 28, 2009
Perl : Get Number of elements from hash

How to get the number of elements a Perl hash holding?

Using the keys() function of Perl, you can easily get the count. The function used to return all the keys from the hash as array. But if you use a SCALAR variable, that case it will return you the element count from the hash.

my %hash = (red => 1, blue => 2, green => 3);
my $count = keys(%hash); ## Scalar requested.
print $count;

Is there any other method to get the elements count from a Perl hash? I mean not using a loop.
Posted by Demon at 7:43 AM 0 comments Links to this post
Labels: perl
Wednesday, May 20, 2009
perl: get IP address of your website user

From your Perl/CGI script, you can easily get the remote IP address of the user who is browsing your website. I'm providing a tiny code that will simply print out the IP address of the user.

use CGI; ## load the cgi module

print "Content-type: text/plain; charset=iso-8859-1\n\n";
my $q = new CGI; ## create a CGI object
print $q->remote_host(); ## print the user ip address

The output will be the simply the IP address of the user who will browse the page. You'll find more about the CGI module of Perl at http://perldoc.perl.org/CGI.html
Posted by Demon at 10:22 AM 1 comments Links to this post
Labels: perl
Tuesday, May 5, 2009
Perl: print last element from array

We know an array needs to access with positive integer. But scripting language like Perl, you can access it using Negative number. A negative number means from last. If you use -5, it will give you the 5th element from the array from last. Remember, for negative index, the index start from 1. Means -1 = last index, -2 = second last, and so on.

This example will help you to understand much more clearly.

## initial array
my @array = qw(1 2 3 4 5 6 7 8 9 10);

## print last element from array
print $array[-1] , "\n";

## print second last element from array
print $array[-2] , "\n";

At above example, there are 10 elements. if you provide a negative number which is greater than the total number of elements, you'll get error Use of uninitialized value in print at temp.pl line 2., for example the below code will generate such error.

print $array[-11] , "\n";

The reason is the array doesn't have 11 elements in total.
Posted by Demon at 8:14 AM 0 comments Links to this post
Labels: perl
Perl: Convert HEX string into character string

At my last post http://icfun.blogspot.com/2009/05/perl-convert-character-string-into-hex.html I've mentioned about character string conversion into HEX string.

Now, its time to do the reverse task. You'll be given a Hex string, and you'll need to convert it into character string. The idea will be similar as last one. Just need to pick-up two hex digit each time, and convert them into character code. Below is the code.

## Initial hex
$string = "6162636465666a68696a6b6c6d6e6f707172737475767778";
## upper/lower case won't be a problem
# $string = "6162636465666A68696A6B6C6D6E6F707172737475767778";

## convert each two digit into char code
$string =~ s/([a-fA-F0-9][a-fA-F0-9])/chr(hex($1))/eg;

print "$string\n";

This time using hex() function I have converted the hex code into integer number, and then using chr() function, I have converted the ascii number into it's character code.
Posted by Demon at 7:46 AM 3 comments Links to this post
Labels: perl
Perl: Convert character string into HEX string

Lets learn about converting a character string into a HEX string. For example you have a string "abcd", it will convert it into HEX string as "61626364". Means just take each character from the string, and get its ascii code, and convert it into HEX.

I'm using regular expression (REGEX) to do this conversion. Below is the code.

## Initial string
$string = "abcdefjhijklmnopqrstuvwx";

## convert each character from the string into HEX code
$string =~ s/(.)/sprintf("%x",ord($1))/eg;

print "$string\n";

The above code will convert the provided string string into it's corresponding HEX code. Using regex i'm picking up the each character from the string, and get the ascii code using ord() function. Then using sprintf() I've just printed as HEX code.

If you want the output as UPPERCASE, you'll just need to make %x into %X inside your sprintf() function.

$string =~ s/(.)/sprintf("%X",ord($1))/eg;

The output will be as below for Lowercase, and Upper case:

6162636465666a68696a6b6c6d6e6f707172737475767778
6162636465666A68696A6B6C6D6E6F707172737475767778

The reverse one is at http://icfun.blogspot.com/2009/05/perl-convert-hex-string-into-character.html
Posted by Demon at 7:38 AM 3 comments Links to this post
Labels: perl
Thursday, April 30, 2009
Get the N-th Bit value of any Integer number

Once again bitwise operations guys. This time we'll know about finding the nth bit value of any 31 bit positive integer number. For example you have a number 120, and you want to get the 7th bit of the number. Here is a function in C/C++ code. But you can convert the code into Perl/Python/Java/PHP/Ruby or whatever you want. The basic is the same.

The bit position are start from left to right.

/**
* Function takes the decimal number
* Function takes the Nth bit (1 to 31)
* Return the value of Nth bit from decimal
*/
int get_bit(int decimal, int N){

// Shifting the 1 for N-1 bits
int constant = 1 << (N-1);

// if the bit is set, return 1
if( decimal & constant ){
return 1;
}

// If the bit is not set, return 0
return 0;
}

The above function will take a 31 bit integer number, and the second parameter is the N(1 to 31), means which position you are interested. Here is few example code to use the function

printf("%d\n", get_bit(3,1));
printf("%d\n", get_bit(12100,7));
printf("%d\n", get_bit(12731273,29));
printf("%d\n", get_bit(2111823716,18));

The output will be:
1
1
0
1

1st bit value of 3 is = 1
7th bit value of 12100 is = 1
29th bit value of 12731273 is = 0
18th bit value of 2111823716 is = 1

Bit-wise operations are fun to use, and faster too. The example is I've given is very basic, and the syntax will work for almost every programming languages. So you can convert the tiny C/C++ code into others. I'll appreciate if anyone convert that into other language, and post as a comment here.
Posted by Demon at 8:37 AM 0 comments Links to this post
Labels: C/C++, java, perl, php, python, ruby

Log in Script Using PHP

noreply@blogger.com (Anonymous) — Mon, 23 Mar 2009 19:33:00 -0700

Overview

In this tutorial create 3 files
1. main_login.php
2. checklogin.php
3. login_success.php

Step
1. Create table "members" in database "test".
2. Create file main_login.php.
3. Create file checklogin.php.
4. Create file login_success.php.
5. Create file logout.php

Create table "members"

CREATE TABLE `members` (
`id` int(4) NOT NULL auto_increment,
`username` varchar(65) NOT NULL default '',
`password` varchar(65) NOT NULL default '',
PRIMARY KEY (`id`)
) TYPE=MyISAM AUTO_INCREMENT=2 ;

Create file main_login.php

Member Login
Username	:
Password	:

Create file checklogin.php

Create file login_success.php

// Check if session is not registered , redirect back to main page.
// Put this code in first line of web page.

Login Successful

Logout.php

// Put this code in first line of web page.

For PHP5 User - checklogin.php

// Host name
$username=""; // Mysql username
$password=""; // Mysql password
$db_name="test"; // Database name
$tbl_name="members"; // Table name

// Connect to server and select databse.
mysql_connect("$host", "$username", "$password")or die("cannot connect");
mysql_select_db("$db_name")or die("cannot select DB");

// Define $myusername and $mypassword
$myusername=$_POST['myusername'];
$mypassword=$_POST['mypassword'];

// To protect MySQL injection (more detail about MySQL injection)
$myusername = stripslashes($myusername);
$mypassword = stripslashes($mypassword);
$myusername = mysql_real_escape_string($myusername);
$mypassword = mysql_real_escape_string($mypassword);

$sql="SELECT * FROM $tbl_name WHERE username='$myusername' and password='$mypassword'";
$result=mysql_query($sql);

// Mysql_num_row is counting table row
$count=mysql_num_rows($result);
// If result matched $myusername and $mypassword, table row must be 1 row

if($count==1){
// Register $myusername, $mypassword and redirect to file "login_success.php"
session_register("myusername");
session_register("mypassword");
header("location:login_success.php");
}
else {
echo "Wrong Username or Password";
}

ob_end_flush();
?>

Log In script Using Perl

noreply@blogger.com (Anonymous) — Mon, 23 Mar 2009 19:10:00 -0700

Log In script Using Perl

Login.pl

#!/www/perl/bin/perl.exe
print "Content-type: text/html\n\n";
use CGI;
use CGI::Carp qw/fatalsToBrowser warningsToBrowser/;
use CGI::Session ( '-ip_match' );

$q = new CGI;

$usr = $q->param('usr');
$pwd = $q->param('pwd');

if($usr ne '')
{
# process the form
if($usr eq "demo" and $pwd eq "demo")
{
$session = new CGI::Session();
print $session->header(-location=>'index.pl');

}
else
{
print $q->header(-type=>"text/html",-location=>"login.pl");
}
}
elsif($q->param('action') eq 'logout')
{
$session = CGI::Session->load() or die CGI::Session->errstr;
$session->delete();
print $session->header(-location=>'login.pl');
}
else
{
print $q->header;
print <
HTML
}

Index.pl

#!/www/perl/bin/perl.exe
print "Content-type: text/html\n\n";
# index.pl
use CGI;
use CGI::Carp qw/fatalsToBrowser warningsToBrowser/;
use CGI::Session ( '-ip_match' );

$session = CGI::Session->load();
$q = new CGI;

if($session->is_expired)
{
print $q->header(-cache_control=>"no-cache, no-store, must-revalidate");
print "Your has session expired. Please login again.";
print "
login";
}
else
{
print $q->header(-cache_control=>"no-cache, no-store, must-revalidate");
print "

Welcome";
print "Logout";
}

My Favorite Tutorial for Perl

noreply@blogger.com (Anonymous) — Thu, 19 Mar 2009 03:41:00 -0700

My Favorite Tutorial for Perl

Part Time Jobs

noreply@blogger.com (Anonymous) — Thu, 19 Mar 2009 03:33:00 -0700

Earn Rs.2000 daily. No Investment.

Wanted Online Internet job workers. Job is only through Internet. Work part time. You can earn Rs.750-2000/- daily. These are genuine Internet jobs. No Investment required. Only serious enquires please. For more details visit http://www.earnparttimejobs.com/index.php?id=349564

Interview Question And Answers

noreply@blogger.com (Anonymous) — Fri, 5 Sep 2008 09:11:00 -0700

http://myitcareer.org/>

Technical Books

noreply@blogger.com (Anonymous) — Fri, 5 Sep 2008 08:56:00 -0700

http://www.btebook.com/0-01a8edbf9d27cebe.htm

DEVELOPER

PHP Interview Questions

Interview Questions

Top 200 PHP interview questions and answers are below

Amulyam site review

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Perl Regular Expressions

Log in Script Using PHP

Log In script Using Perl

Welcome"; print "Logout"; }

My Favorite Tutorial for Perl

Part Time Jobs

Interview Question And Answers

Technical Books

Welcome";
print "Logout";
}