Constraints can be specified when a table is created (with the CREATE TABLE statement) or after the table is created (with the ALTER TABLE statement). We will focus on the following constraints:

• NOT NULL
• UNIQUE
• PRIMARY KEY
• FOREIGN KEY
• CHECK
• DEFAULT

The next chapters will describe each constraint in details.

Related posts:

1. SQL SELECT Statement
2. SQL Join
3. The SQL SELECT INTO Statement

SQL CREATE TABLE Syntax

CREATE TABLE table_name ( column_name1 data_type, column_name2 data_type, column_name3 data_type, ….. )

The data type specifies what type of data the column can hold. For a complete reference of all the data types available in MS Access, MySQL, and SQL Server, go to our complete Data Types reference.

CREATE TABLE Example

Now we want to create a table called “Persons” that contains five columns: P_Id, LastName, FirstName, Address, and City.

We use the following CREATE TABLE statement:

CREATE TABLE Persons ( P_Id int, LastName varchar(255), FirstName varchar(255), Address varchar(255), City varchar(255) )

The P_Id column is of type int and will hold a number. The LastName, FirstName, Address, and City columns are of type varchar with a maximum length of 255 characters.

The empty “Persons” table will now look like this:

The empty table can be filled with data with the INSERT INTO statement.

Related posts:

1. SQL INSERT INTO Statement
2. SQL UPDATE Statement
3. The DELETE Statement

SQL CREATE DATABASE Syntax

CREATE DATABASE database_name

CREATE DATABASE Example

Now we want to create a database called “my_db”. We use the following CREATE DATABASE statement:

CREATE DATABASE my_db

Database tables can be added with the CREATE TABLE statement.

Related posts:

1. SQL SELECT Statement
2. SQL UPDATE Statement
3. The DELETE Statement

The SELECT INTO statement is most often used to create backup copies of tables. We can select all columns into the new table:

SELECT *INTO new_table_name [IN externaldatabase] FROM old_tablename

Or we can select only the columns we want into the new table:

SELECT column_name(s) INTO new_table_name [IN externaldatabase] FROM old_tablename

SQL SELECT INTO Example

Make a Backup Copy – Now we want to make an exact copy of the data in our “Persons” table. We use the following SQL statement:

SELECT * INTO Persons_Backup FROM Persons

We can also use the IN clause to copy the table into another database:

SELECT * INTO Persons_Backup IN ‘Backup.mdb’ FROM Persons

We can also copy only a few fields into the new table:

SELECT LastName,FirstName INTO Persons_Backup FROM Persons

SQL SELECT INTO – With a WHERE Clause

We can also add a WHERE clause. The following SQL statement creates a “Persons_Backup” table with only the persons who lives in the city “Sandnes”:

SELECT LastName,Firstname INTO Persons_Backup FROM Persons WHERE City=’Sandnes’

SQL SELECT INTO – Joined Tables

Selecting data from more than one table is also possible. The following example creates a “Persons_Order_Backup” table contains data from the two tables “Persons” and “Orders”:

SELECT Persons.LastName,Orders.OrderNo INTO Persons_Order_Backup FROM Persons INNER JOIN Orders ON Persons.P_Id=Orders.P_Id

Related posts:

1. SQL INSERT INTO Statement
2. SQL UPDATE Statement
3. SQL INNER JOIN Keyword

Notice that each SELECT statement within the UNION must have the same number of columns. The columns must also have similar data types. Also, the columns in each SELECT statement must be in the same order.

SQL UNION Syntax

SELECT column_name(s) FROM table_name1 UNION SELECT column_name(s) FROM table_name2

Note: The UNION operator selects only distinct values by default. To allow duplicate values, use UNION ALL.

SQL UNION ALL Syntax

SELECT column_name(s) FROM table_name1 UNION ALL SELECT column_name(s) FROM table_name2

PS: The column names in the result-set of a UNION are always equal to the column names in the first SELECT statement in the UNION.

SQL UNION Example

Look at the following tables:

“Employees_Norway”:

“Employees_USA”:

Now we want to list all the different employees in Norway and USA.

We use the following SELECT statement:

SELECT E_Name FROM Employees_Norway UNION SELECT E_Name FROM Employees_USA

The result-set will look like this:

Note: This command cannot be used to list all employees in Norway and USA. In the example above we have two employees with equal names, and only one of them will be listed. The UNION command selects only distinct values.

SQL UNION ALL Example

Now we want to list all employees in Norway and USA:

SELECT E_Name FROM Employees_Norway UNION ALL SELECT E_Name FROM Employees_USA

Result

Related posts:

1. SQL AND & OR Operators
2. SQL TOP Clause
3. SQL IN Operator

Installing this Wordpress.com Stats plugin after that need is to put in API Key and the rest is automatic. Once it’s running it’ll begin collecting information about page views, which posts and pages are the most popular, where your traffic is coming from, and what people click on when they leave. It’ll also add a link to your dashboard which allows you to see all stats on a single page.

Finally, because all of the processing and collection runs on their servers and not yours, WordPress.com Stats plugin doesn’t cause any additional load on your hosting account. In fact, it’s one of the fastest stats systems, hosted or not hosted, that you can use.

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1. Stats Plugin Wordpress (Not Working)
2. Stats Plugin by W3Counter
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To change your Yahoo! account information:

1. Click here to go to your Account Info page. You may be prompted to sign in or re-enter your password for security. Once you have correctly entered your password, you will be directed to the Account Info page.
2. From the Account Info page you can edit:
   • Profile Information: Click Edit profile details to go to the page where you can change personal information such as your name, location, relationship status, place of employment, schools attended, and so on.
   • Contact Information: Click Update your contact information to update your phone numbers, addresses, and email accounts that you share with Yahoo! and with your Yahoo! connections. Click Choose how Yahoo! contacts you to update your mobile phone or alternate email address.
   • Sign-In and Security:
     • Click Change your password to change the password you use to log in to your Yahoo! account.
     • Click Update password-reset info to change your alternate email address, mobile phone number, or secret questions that Yahoo! needs to reset your password.
     • Click Create a sign-in seal to add a level of security to your personal information.
     • Click Manage/Create your OpenID to create or change your OpenID identifiers.
     • Click Link your account with other sites to determine which third-party applications and devices as well as Yahoo! applications you want to remain signed-in to.
     • Click Change sign-in settings to change how often Yahoo! asks you to enter your password.
   • Account Settings:
     • Click Manage your Yahoo! aliases to create or change your aliases.
     • Click Set language, site, time zone to change these settings for the country and time zone in which you want to display your Yahoo! content.
   • Notifications and Subscriptions:
     • Click View your Yahoo! premium services to see which services you subscribe to and when they expire.
     • Click Update newsletter & marketing options to manage what types of messages we send you and how we send them and to subscribe/unsubscribe from newsletters.
     • Click Set up Yahoo! Alerts to select which alerts you want Yahoo! to send to your Yahoo! Mail, Messenger, or mobile phone.

Related posts:

1. Yahoo! Messenger Multiple Accounts
2. Yahoo! Messenger Multiple Tabs
3. Unlocking the Sample User Account

It also allows you to send as e-mail attachment in the PDF and XPS formats in a subset of these programs.

Click here t download add in

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1. Open Office 2007 Documents in Office 2003
2. Change Yahoo! Account Information

Get the Microsoft Office Compatibility Pack for the Word, Excel, and PowerPoint 2007 File Formats. The Compatibility Pack will let you read Office 2007 documents in Microsoft Office 2000, Office XP, or Office 2003. So you can open a .docx file with Word 2003 or .pptx with PowerPoint 2003.

Download Office 2007 Compatibility Pack

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1. Save as PDF or XPS

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