MS SQL Server Concepts and Programming Question: Download MS SQL Server PDF
What Happens If You Insert a Duplicate Key for the Primary Key Column in MS SQL Server?
Answer:
If your table has a primary key column, and you are trying to insert a new row with duplicate key value on the primary key column, you will get an error. The reason is simple - Primary key column does not allow duplicate values. The following tutorial exercise gives you a good example:
SELECT * FROM ggl_links
INSERT INTO ggl_links VALUES (101,
'www.globalguideline.com',
NULL,
0,
'2006-04-30')
GO
Msg 2627, Level 14, State 1, Line 1
Violation of PRIMARY KEY constraint
'PK__ggl_links__03317E3D'. Cannot insert duplicate
key in object 'dbo.ggl_links'.
The statement has been terminated.
You are getting this error, because value "101" has already been used by an existing row.
SELECT * FROM ggl_links
INSERT INTO ggl_links VALUES (101,
'www.globalguideline.com',
NULL,
0,
'2006-04-30')
GO
Msg 2627, Level 14, State 1, Line 1
Violation of PRIMARY KEY constraint
'PK__ggl_links__03317E3D'. Cannot insert duplicate
key in object 'dbo.ggl_links'.
The statement has been terminated.
You are getting this error, because value "101" has already been used by an existing row.
| Previous Question | Next Question |
| How to provide column names in INSERT Statements in MS SQL Server? | How To Insert Multiple Rows with One INSERT Statement in MS SQL Server? |