Learn about data definition Language

Hello friend!! You will learn about SQL and Sql command from this blog. As we know that whenever we make any website whether  it on asp.net or jsp then we requirement of database this is done by a tool named as Microsoft SQL Server Management for  access and manipulate the database .Lets we study about SQL Server.

SQL Server !!

First of all before study about SQL Server a question is come in our mind that is what is the SQL Server and  why we use it.

What is SQL Server???

             SQL is stand for Structure Query Language Microsoft SQL Server is a relational database management system developed by Microsoft. It us a  software product whose primary function is to store and retrieve data as requested by other software application and retrieve data on the same computer or those running on another computer across a network.

Some Selected Point:

·         SQL Server is executing queries against a database.

·         SQL Server is retrieve data from database.

·         SQL Server is insert records in a database.

·         SQL Server is update, delete, create records and database.

·         SQL Server is set of permission on the tables, procedure and views.

SQL Server is categorized is into four part as given below..

1.     Data Definition Language (DDL).

2.     Data Manipulation Language (DML).

3.     Data Control Language (DCL).

4.     Data Query Language (DQL). 

Data Definition Language:

              DDL is used to define the database, datatype, structure and constraints on the data. There is some statement of DDL which is given below.

·         Create 

·         Alter

·         Drop

Create: This statement is used to create table and database in the database. The screen will show as given below.

Syntax:          CREATE TABLE TABLE_NAME 

Alter: Alter statement is used to add, modify and delete column in an existing table. The Screen will show as given below.

To add a column in database use below syntax:

ALTER TABLE TABLE_NAME ADD COLUMN_NAME DATATYPE

To delete a column in database use below syntax:

ALTER TABLE TABLE_NAME DROP COLUMN_NAME

Drop: Drop statement is used to delete table. The output screen is as given below.

Syntax:   DROP TABLE_NAME

I hope this post will help you ..

If you've some question regarding to this article then just post your comment.Your comment will be appropriate.. 

Posted in: SQL SERVER