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SQL Server FAQ - Duplicate Key Error on Primary Key Columns
(Continued from previous topic...)
What Happens If You Insert a Duplicate Key for the Primary Key Column?
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 fyi_links
INSERT INTO fyi_links VALUES (101,
Msg 2627, Level 14, State 1, Line 1
Violation of PRIMARY KEY constraint
'PK__fyi_links__03317E3D'. Cannot insert duplicate
key in object 'dbo.fyi_links'.
The statement has been terminated.
You are getting this error, because value "101" has already been used by an existing row.
(Continued on next topic...)
- What Are DML (Data Manipulation Language) Statements?
- How To Create a Testing Table with Test Data?
- How To Insert a New Row into a Table with "INSERT INTO" Statements?
- How To Use Column Default Values in INSERT Statements?
- How to provide column names in INSERT Statements?
- What Happens If You Insert a Duplicate Key for the Primary Key Column?
- How To Insert Multiple Rows with One INSERT Statement?
- How To Update Values in a Table with UPDATE Statements?
- How To Update Multiple Rows with One UPDATE Statement?
- How to use old values to define new values in UPDATE statements?
- Is the Order of Columns in the SET Clause Important?
- How To Use Values from Other Tables in UPDATE Statements?
- What Happens If the UPDATE Subquery Returns No Rows?
- What Happens If the UPDATE Subquery Returns Multiple Rows?
- How To Delete an Existing Row with DELETE Statements?
- How To Delete Multiple Rows with One DELETE Statement?
- How To Delete All Rows with DELETE Statements?
- How To Delete All Rows with TRUNCATE TABLE Statement?