ORACLE VIRTUAL CLASSROOM

OBIEE WHAT DOES IT MEAN?

2012-09-17T22:24:00.000-07:00

Oracle Business intelligence Enterprise edition (OBIEE)

According to Oracle, Oracle Business Intelligence Enterprise Edition 11g (OBIEE) is a comprehensive business intelligence platform that delivers a full range of analytic and reporting capabilities. Designed for scalability, reliability, and performance, Oracle Business Intelligence Enterprise Edition 11g delivers contextual, relevant and actionable insight to everyone in an organization, resulting in improved decision-making, better-informed actions, and more efficient business processes. Oracle also provides the industry’s only multi-sourced BI applications, as well as market-leading performance management applications that are powered by this BI platform.

That being said. Oracles BI strategy is simple they merged best in class enterprise bi platform with performance management applications from Hyperion , pre built analytic application that spans the operation business side intergrated into a uniform system !

Business intelligence is on top of the CIO list. Today organizations are trying to recognize the value of consolidating business intelligence tools. Previously they had their data in disparate tools based on different departments.
Oracles platform can access the data from heterogenous system in org and deliver it to the users. You can generate Management dashboards, reports, adhoc queries advanced OLAP analysis. Oracles intelligence platform has the major advantage of scalability, A
lot of bi tools out there evolved from client server system. Model once deploy everywhere

LAUNCHING SOON! A NEW TUTORIAL On ORACLE DATABASE 11G OCA!

2012-06-07T15:23:00.000-07:00

Get your OCA CERTIFICATION ITS EASY!

HOW TO DOWNLOAD ORACLE 11G FOR FREE

2012-04-12T14:20:00.000-07:00

Check but a free tutorial on how to download oracle for free

TYPES OF DATATYPES FOUND IN AN ORACLE DATABASE!

2012-03-19T12:40:00.003-07:00

Types of Oracle Database Datatypes

varchar2 this is the most common datatype it allows you to store alphanumeric characters. The length of varchar2 is 4000 bytes or characters. This was what set Oracle apart from other databases in prior years. While other databases had lengths up to 2000 Oracle had its character length set at 4000
Number datatype: allows you to store an interger as well as decimal values
date datatype not to be confused with the time stamp datatype stores the date value - the default way of storing date in Oracle is DD-MON-YY
Timestamp related to the date dataype but instead stoeres information witth a higher sense of precision and accuracy. It stores the date up to the second eg 14 -OCT-09 01.25.07.00002 PM
Clob datatype - stores large objects that are over four gigabytes in size
blob datatype allows for the storage of large binary objects a great example of this would be video.

Hope you enjoyed this post.

WHAT IS THE SGA IN ORACLE AND WHAT IS IN IT??

2012-03-18T14:20:00.002-07:00

Oracle memory is called the SGA: there are different components of the SGA. Every database will have a section within the memory (SGA) referred to as the database buffer cache!

It is split up into little blocks in memory called the oracle data blocks. Each one of these blocks will be 8k in size.

There is an algorithm that gets applied to the database buffer pool, it is the LRU (least recently used).. As the blocks get touched they get placed toward the LRU to get written to disk, Oracle keeps the most used in memory for easier access.

Another area in the SGA is the Shared Pool which is used to reduce parsing- there are two sections within shared pool.

Library Cache: Inside the library Cache, you have the actual text of the sql statement .You will also have as compiled section of the SQL code which is called META CODE. The third area you have in the library is the execution plan. This shows how the query is going to retrieve the rows.
The second piece of the shared pool is the dictionary cache. It contains the names of objects that have been touched recently. Your privileges and rows is stored here too. So if the employee table has been accessed recently, it is placed in the shared pool

There are other pieces within the SGA. I will list two more in this post:

Most databases will have the JAVA pool in the SGA which stores your JAVA.

If you are using the RMAN utility in oracle you would want to configure your LARGE pool within the SGA.

HOW DO YOU CREATE THE ORACLE PASSWORD FILE?

2012-03-18T14:02:00.001-07:00

Oracle password file is created using a utility called ORAPWD! You will also use this utility to make changes.

WHAT ARE YOUR ONLINE REDO LOGS?

2012-03-17T15:35:00.000-07:00

An online redo log tracks all of your changes to your tables. In order to get started, you need a minimum of two to get started on your online database; this redo log group is like a recorder, that records changes going on in your oracle database. However, you will end up having more than one group. You could end up with three groups or more.

Oracle recommends that you multiplex your redo logs. When this redo log gets filled oracle does what is called a check point and then it writes to the next group.

This redo logs are used for database recovery. When the final group fills up it goes back to the first and writes to the first group (basically overwriting what was currently in the first group); but if you are in archive log mode, when the first group fills the information is copied onto Archived redo logs (the default is no archive log mode which overwrites the data).

If you have not archived the first log and your directory is full and you are running on archive log mode. Your database will hang.

Here is a basic definition of an oracle database

An oracle database is defined as three types of files, control files, data files and the redo logs! Any questions.

THREE MOST IMPORTANT PARTS OF AN ORACLE DATABASE!

2012-03-17T15:17:00.000-07:00

Before understanding the oracle database in depth, it is important to know the most important pieces in any database. This time we are discussing the oracle database.

Storage - Think of it this way, your data needs to be stored in a table, which belongs to a logical area called table space and a table space gets mapped to a physical file called a data file. (which essentially uses disk storage).
Memory - This is called the System global Area (SGA) in Oracle.
Processes - The third piece in an Oracle database is the disk processes.

Datafiles store tables, indexes and rollback segments (undo segments in 9i on wards) and temporary files.

The most important logical view for a DBA is the dba_data_files - this has information about the datafiles.

Another file that controls the structure of your database is your datafiles. It is recommended that you have at least 3 control files on sepererate disk drives. This shows how when your database got created etc All three control files need to look exactly alike.

There is a v$ that will tell you the path of your control file and this is the v$controlfiles.

TYPES OF DATABASE ADMINISTRATORS!

2012-02-01T14:44:00.000-08:00

Here is breakdown structure of the various types of database administrators! Can you tell which one fits your personality?

Systems or Operational DBA
Architect
Applications DBA
Data DBA
Internet DBA also a web dba!

The Operational DBA keeps the operations running, loads the database, performs the batch work , etl loads etc Backup and recovery that good stuff!

Now here is another the Data Architect works with the developers to figure out the structure and how to effectively create the structures(tables) and how they can be created within the database; how you store information is important, making sure the empty fields are at the end of the row.

Next we have the good old Applications DBA whose task is to support the applications that also have databases included for example Oracle financials, oracle E business suite!

Data DBA helps intergrate databases for example getting information from differnt sources and integrating it together

The web dba gets to understand how the process within the web works. Which application server, webserver is down.

HOW THE DBA EVALUATES HARDWARE!

2012-01-24T11:20:00.000-08:00

The DBA evaluates hardware resources by checking whether or not there are enough disk drives available to install the oracle database software.

What exactly does this mean, but first off, welcome you have just gotten hired as the new Database Administrator. Your first task as directed in this small shop is to install the newly acquired oracle database software. What do you need to do? You are given a server and told go ahead and get started.

You have to check whether or not you have enough disk drives required.
How much memory is available for the oracle instance you will run (a good rule of thumb is to check the system documentation to learn what the amount you need)
Some database administrator have spread sheets that give an estimate of how much the data is going to grow and they use this as an estimate.

WHO IS THE ORACLE DBA?

2012-01-19T23:22:00.000-08:00

This is my first major post before delving into what exactly the Oracle DBA is required to do. Let us first simplify who an Oracle DBA is and what roles and responsibilities come with the position.

photo myfootpath

An database administrator (DBA) is the one who administers the Oracle database server.
Responsibilities may vary depending on the size of the company the Oracle DBA works for. For instance, a small company in most cases might have just one Oracle Database Administrator who administers the database for applications and users. While in a Major company, what you would find are several people tasked as Database Administrators with different areas of specialization.

Now here is a list depicting the roles and responsibilities of the DBA

The DBA evaluates hardware resources , are there enough disk drives available to install the oracle database software etc
The DBA installs the software
The dba plans the database , knows how much he or she expects the database to grow in the future
The DBA creates the database
The DBA creates users in the database and ensures that they are identified with the right roles within the database
The DBA will then next have to implement the logical structures within the database.
The DBA creates a backup of the newly implemented database
Finally the DBA will tune the database and implement a way to monitor the health of the database.

In future posts, I will discuss what exactly each one of the following responsibilities entails. For now know this, a database administrators main task is to ensure the database is up and running and ongoing with minimal downtime. If you are an aspiring DBA reading this, rest assured it is an exciting career choice.

WHAT KIND OF A DBA ARE YOU?

2012-01-15T20:21:00.000-08:00

So earlier today I took a test on basically figuring out what kind of DBA I am and here is the result!

The scientist DBA is brilliant and sometimes shy, hates disorder, chaos and conundrums, and greatly enjoys diving into the internals of their database.

The scientist DBA tends to have a love of music and gravitates towards degrees in “pure” majors such as History, English, Math, or Physics.

Scientist DBAs usually keeps their offices neat and orderly, with everything in its proper place. Their motto is “Prove it,” and they love to try out their database hypotheses on their test systems.

Attention to detail — Scientist DBAs like order in every area of their lives and their database is no exception. Every tablespace and table must stay optimized, and the scientist DBA gets visibly disturbed when a table takes too many extents or when a tablespace becomes fragmented. They miss nothing, and pride themselves on their close attention to every detail of their database.

High professional standards — The scientist DBA believes that a database can be described with mathematical equations and every assertion about database behavior can be proven with experimentation. They sometimes require all developers to “prove” their changes in the test database, before allowing changes in production. The scientist DBA hates “rules-of-thumb” and revels in finding exceptions to any general assertion about database behavior.

Highly reliable — Scientist DBAs spend their days in the test systems, posing hypotheses and cranking out scripts to “prove” their theories before making changes to their production system. The scientist DBA is very careful and meticulous and will always justify every database change (often with extraordinary detailed experimental evidence) before changing their production database.

Extremely eloquent — Some, (but not all) of the scientist DBAs can be identified by their grandiloquent prose. These DBAs love to use obscure words and complex verbal syntax, and normally keep an Oxford English Dictionary (OED) close at-hand. They love puns and double entendres, and enjoy using obsolete words that have not been popular since the early 1800s.

Not bad so here is what this blog will focus on Database Adminstration and of course other Oracle tools you might find exciting; so welcome to the oracle virtual Classroom

RMAN CONTROLFILE BACKUP

2011-09-23T21:11:00.000-07:00

Welcome to oracle virtual classroom where we simplify your understanding of all thing Oracle Software related. We hope you would join us on this journey as we proceed. Today we will be starting off with how to back up your control file using RMAN (oracle's recovery manager). What is a control file in the first place and why do we need to back it up?

Well for starters the control file in an oracle database stores the status of the physical structure of the database. The control file is a critical aspect of the database, without it the database will not continue its operations and that is the last thing you want to happen to your database.

So here is how your would use rman controfile backup to make a copy of your control file in case your end up with a corrupt file, you will be able to restore your database.

First off connect to RMAN via the command line

$ rman
RMAN> connect target user/password
RMAN> connect catalog user/password
To back up the whole database:
RMAN> backup database; * if you want back up the database to a specific file use: RMAN> BACKUP DATABASET FORMAT ‘/backup/oracle/%d-%T-%s-%P’;
Notice that the formatting of this information varies by platform.
  %d The name of the database.
  %D The current day of the month (in format DD)
  %M The month (format MM)
  %Y The year (YYYY)
  %T The year, month, and day (YYYYMMDD)
  %F Combination of DBID, day, month, year, and sequence
  %p The piece number within the backup set.
  %s The backup set number.
  %t The backup set time stamp, which is a 4-byte value

Now the easy way to back up the control file is to issue the following command:
RMAN> backup controlfile;

You can also set the database to backup the file automatically that way you need to constantly worry about the file and here is how you would do that

Configuring RMAN to Automatically Backup the Control File and SPFILE

Simply set CONFIGURE CONTROLFILE AUTOBACKUP to ON, then RMAN automatically creates a control file and an SPFILE backup after you run the BACKUP or COPY commands.