Skip to main content

IDENTITY COLUMNS


Identity column specifies when ever new value is inserted into table. Identity column automatically inserted value into column.

Identity Column can be specified at the time of creation of table.

CREATE TABLE Employee
(
 EMPID INT IDENTITY(1,1),
 EMPNAME VARCHAR(50),
 SALARY INT
)

In above table creation script EMPID column specifies IDENTITY property i.e., whenever a new row inserted into a Employee table EMPID Column will automatically value is inserted.

INSERT INTO Employee (EMPNAME,SALARY)VALUES('RAKESH',7000)

INSERT INTO Employee (EMPNAME,SALARY)VALUES('ALI',12000)

SELECT * FROM Employee
When u run above select statement is the following result is





























if u are trying insert value into identify columns .it will give error.

INSERT INTO Employee (EMPID,EMPNAME,SALARY)VALUES(1,'RAKESH',7000)

Msg 544, Level 16, State 1, Line 1
Cannot insert explicit value for identity column in table 'Employee' when IDENTITY_INSERT is set to OFF.

 Please refer this link HOW TO INSERT VALUE INTO IDENTITY COLUMN



Labels:

Comments

Post a Comment

Popular posts from this blog

Coalesce function

Coalesce function returns the first non-null value among the arguments. Syntax: Coalesce (expression [,..n]) Here is example using Coalesce function Example 1 DECLARE @Str1 varchar ( 10 ), @str2 varchar ( 20 ), @Str3 varchar ( 20 ) SET @Str2 = 'Sql' , @Str3 = 'Server' SELECT COALESCE ( @Str1 , @str2 , @Str3 ) As [Coalesce] In above example @Str2 value is ‘Sql’ , @str3 value is ‘Server’  and @str1 values is Null because it not assigned any value . Output: It return’s “Sql” because Coalesce function return’s first non null value. Example 2: Coalesce in select statement. IF OBJECT_ID ( 'Employee' , 'U' ) IS NOT NULL DROP TABLE Employee CREATE TABLE Employee (   ID INT IDENTITY ( 1 , 1 ) PRIMARY KEY ,   NAME VARCHAR ( 20 ),   SALARY INT ) INSERT INTO Employee   ( NAME , SALARY ) VALUES ( 'Rakesh' , 5000 ),(NULL, 6000 ),( 'Naresh...
1 comment
Read more

CONCAT FUNCTION IN SQL SERVER 2012

Concat function is used concatnating the values among the different arguments. Syntax: Concat([String1],[String2]..[StringN]);  DECLARE @FName VARCHAR ( 50 ), @LName VARCHAR ( 50 ); SET @FName = 'Rakesh' ; SET @LName = 'Kalluri' ; SELECT CONCAT ( @FName , ' ' , @LName ) as [FullName] ; Output: Rakesh Kalluri --Before SQL 2012 Versions we can use like this way DECLARE @FName VARCHAR ( 50 ), @LName VARCHAR ( 50 ); SET @FName = 'Rakesh' ; SET @LName = 'Kalluri' ; SELECT @FName + ' ' + @LName as [FullName] ; Output: Rakesh Kalluri --But Before SQL 2012 Versions there are 2 problems when we  contacting . --1.Need to replace NULL Value to Empty.if we directly concat NULL Value the  Entire  result also NULL. --Before 2012: DECLARE @FName VARCHAR ( 50 ), @LName VARCHAR ( 50 ); SET @FName = 'Rakesh' ; SELECT @FName + ' ' + @LName a...
Post a Comment
Read more

Variables in T-SQL

Variables can be used to store the data in temporally based on data type. Variable name begin with @ symbol. There are two types of variables in T-SQL. 1.   Local Variables (It must begin @ symbol). 2.   Global Variables (it must begin @@ symbol) this variables also known as system variables. Syntax Declare a Variable DECLARE   @Variable-Name   DATATYPE EXAMPLE: DECLARE   @Name   VARCHAR ( 100 ) In before 2008 versions of SQL SERVER we declare a variable and assign a value in 2 lines.                 DECLARE   @Name   VARCHAR ( 100 ) SET   @Name = 'LeadFirstSQL' In 2008 and Later versions of SQL SERVER we declare a variable and assign a value in single line. DECLARE   @Name   VARCHAR ( 100 )   = 'LeadFirstSQL' Variables must be declare and used with the same batch. DECLARE   @Name   VARCHAR ( 100 ) ...
Post a Comment
Read more