SQL Introduction

Quick Introduction to SQL: SQL is Structure Query Language. This Query language is used to connect with the database. It is considered as standard language for relation database management systems according to (American National Standards institute). The SQL have own statement, which helps you to perform various tasks such as insert, update or retrieve the data from database, In others word it is a database sub language for querying and modifying relational database. The common relational database using SQL are: Oracle, Microsoft SQL Server,Ingress,Access,etc.Normally. The most database use SQL ,but these database have their own property, which are used on their system. The standard common command used in SQL are" Select"," Insert"," Update","Delete","Create","Drop" and Truncate, which are performed on database.

Data Definition Language: The Data Definition language is used to create,alter,drop or delete a table in database. This include a index through which you can make a link between table in database. The list of Data Definition language are as given below

Statements	Description
Create	The Create Table is used to create a table in database
Alter	The Update is used to alter the table
Drop	The Drop Table is used to drop table in database

Data Manipulation Language :The Data Manipulation Language is used to select, insert into,delete,update from database table. The following keyword perform the particular task are given below:

Statements	Description
Select	The Select is used to display the records available in table.
Update	The Update is used to modify or change in table
Delete	The Delete is used to record from table
Insert into	The Insert into is used to add records into table

Structure of SQL Language

The SQL is a keyword based language. Each statement in SQL start with a unique keyword. The SQL statements include a clauses begin with a keyword. SQL syntax is independent of case-sensitive.

Syntax for SQL Statement

1) Elements of database are tables,columns,views,user,schemas,names,which begin with a letter(a-z), digits(0-9) and underscore(_).

2)literals used in SQL Statement are quoted strings,datetime values, numeric values.

3)delimiter are + -,( ),=,<>,*,||,?;

Names in the database is case sensitive, include spaces and delimiters, include keywords surrounds with double quotation marks("").For Example

"SELECT","Create""INSERT","DELETE"etc.