Introduction: In this article I am
going to share How to create table in sql server database having primary key
and auto increment column (IDENTITY)
In previous articles i explained Sql server query to get second,third,fourth or nth highest salary of employee and Backup and restore sql server database and 20 main differences between Stored procedures and Functions and Sql server stored procedure for insert,update,delete,bind and search operation in table and SELF JOIN in SQL SERVER with example
Implementation: Let’s create the
table having primary key and auto incremented column as:
CREATE TABLE tbBooks
(
BookId INT IDENTITY(1,1) PRIMARY KEY,
BookName VARCHAR(100) ,
Author VARCHAR(100),
Publisher VARCHAR(200),
Price DECIMAL(18,2)
)
In above example BookId is
Primary Key so it will be unique in the table and to specify that it should
start at value 1 and increment by 1 I have written IDENTITY (1,1) . IDENTITY
Keyword with seed or start value and increment value is used to set an auto
increment column. Here seed value is 1 and increment value is 1.
Now Suppose we want to start the
BookId with value 1000 and increment it by 1 then we need to set IDENTITY(1000,1).
So now the starting value of BookId will be 1 and it will automatically increment
by 1 for each record inserted in table. For
example first book record will have BookId 1000, second record will have 1001,
third will have 1002 and so on.
Now let’s insert some data in
above created table using the following queries
INSERT INTO tbBooks(BookName,Author,Publisher,Price) VALUES('Sql Server For Beginners','Lalit','Raghuvanshi Publications',1200)
INSERT INTO tbBooks(BookName,Author,Publisher,Price) VALUES('Sql Server Tips For Beginners','Neha','Neha Publications',1250)
INSERT INTO tbBooks(BookName,Author,Publisher,Price) VALUES('Learn Sql Server in 60
days','Rozy','Rozy Publications',1000)
Now check inserted data using the
query
SELECT * from tbBooks
Output will be:
BookId
|
BookName
|
Author
|
Publisher
|
Price
|
1
|
Sql Server For Beginners
|
Lalit
|
Raghuvanshi Publications
|
1200.00
|
2
|
Sql Server Tips For Beginners
|
Neha
|
Neha Publications
|
1250.00
|
3
|
Learn Sql Server in 60 days
|
Rozy
|
Rozy Publications
|
1000.00
|
Note: Have you noticed we have
not inserted any value in BookId column still it showing 1, 2, 3 because It is
being auto generated for each record inserted.
Points to remember
- We must either set both the seed and increment value or none of them. If we don’t specify seed and incremental value then the default is (1,1).
- IDENTITY Property can only be assigned to columns having INT data type and we can only create one identity column per table
Now over to you:
1 comments:
Click here for commentshow to diaplay the primary key error please reply me...
If you have any question about any post, Feel free to ask.You can simply drop a comment below post or contact via Contact Us form. Your feedback and suggestions will be highly appreciated. Also try to leave comments from your account not from the anonymous account so that i can respond to you easily..