SQL

SQL :

SQL - Structured Query Language..

 SQL Mainly Use Data & Information are Stored ..

DataBase :

  DataBase is a Collection Of Tables..

 Table :

 Tables are COllection Of Rows and Columns..

2 type Languages

DDL - Data Defination Language 

DML - Data Manipulation Language

  DDL Statements :

              * CREATE 

              * ALTER 

              * DROP

 DCL Statements :

          

                * INSERT

             * UPDATE

             * DELETE

             * SELECT

SQL Constraints :

          PRIMARY KEY

          NOT NULL

          CHECK

          UNIQUE

          FOREIGN KEY

          DEFAULT

SQL Data Types :

         Int

         Varchar(size)

         Float

         Decimal

         Single

         Double

         DateTime

         Identity

Primary Key :

       Not Accepted Null Values..

       Not Accepted Duplicate Values..

       One Table One Primary Only Use..

UNIQUE Key :

     (Same as Primary Key)

     But Is Accepted One Null Value..

     One Table More then Unique Keys are Use..

FOREIGN Key:

    One Table to Another Table Refrences to Use ForeignKey..

    One Table PrimaryKey to Another Table Called as Reference Key..

SQL Objects :

        *  Tables

        *  Stored Procedure

        *  Function 

        *  Trigger

        *  Cursor

        *  Index

        *  View

Stored Procedure :

           Reusability ..

           PreCompailed ..

           Set Of Querys ..

           Perfomance Fast ..

           Less Traffic ..

           Security Of Your Data..

Function :

Function 2 Types..

     *  Aggregate Functions

     *  Scalar Functions

 Aggregate Functions :

          MAX()

          MIN()

          COUNT()

          AVG()

          SUM()

          FIRST()

          LAST()

Scalar Functions :

   UCASE()

   LCASE()

   NOW()

   LENGTH()

 Trigger :

  Insert,UpDate,Delete Get Excuted automatically Trigger is Called..

 INDEX :

  Index Is a Book..(Book Index First Page)..

  table Columns Create INDEX..

  Performance Fast..

 Types:

   Clusted Index

   Non-Clusted Index

 View :

  View Is a Set Of Select Query ..

Delete Truncate:

 Delete Where Condition Use.. 

 Truncate are Not Use for any Conditions..

 Delete Row By Row Delete

 Truncate Table Delete

 Delete Identity Column Not Reset..

 Truncate Identity Column Reset..

 Delete Trigger Fired..

 Truncate Cannot Trigger Fired ..

 Delete is Slowly Record Delete..

 Truncate is Quickly Delete..

 Delete Can Roolback..

 Telete Cannot Roolback..

  

Syntax :

DataBase:

 Create DataBase DataBaseName;

 Use DataBase DataBaseName;

 Create DataBase Vijay_DB;

 Use DataBase Vijay_DB

Table 

 Create Table TableName

  (

     ColumnName DataTypes,

     Name Varchar(250),

     ...,

     ...

  )

 Create Table Actor_Details

  (

    Act_ID Int,

    Act_Name Varchar(100),

    Act_Salary Decimal(10,2)

  )

Insert :

 Insert Into TableName (ColumnName1,ColumnName2,.....)

       Values('aaa','aaa')

 Insert Into Actor_Details(Act_Name,Act_Salary)

       Values('Ajith',10000)

Selecct :

 Select * From TableName;

 Select * From Actor_Details;