Enabling Explicit Identity Column Insertion in SQL Server

In SQL Server, identity columns are used to automatically generate a unique identifier for each row in a table. By default, SQL Server does not allow explicit values to be inserted into an identity column. However, there are situations where you may need to insert a specific value into an identity column, such as when restoring data from a backup or migrating data from another database.

To enable explicit identity column insertion, you can use the IDENTITY_INSERT property. This property can be set to ON for a specific table, allowing you to insert explicit values into the identity column. In this tutorial, we will explore how to use the IDENTITY_INSERT property to enable explicit identity column insertion in SQL Server.

Enabling IDENTITY_INSERT

To enable IDENTITY_INSERT, you can use the following syntax:

SET IDENTITY_INSERT table_name ON;

Replace table_name with the name of the table for which you want to enable IDENTITY_INSERT. Once IDENTITY_INSERT is enabled, you can insert explicit values into the identity column using an INSERT statement.

Inserting Explicit Values

After enabling IDENTITY_INSERT, you can insert explicit values into the identity column using an INSERT statement. For example:

SET IDENTITY_INSERT tbl_content ON;

INSERT INTO tbl_content (id, column1, column2)
VALUES (1, 'value1', 'value2');

SET IDENTITY_INSERT tbl_content OFF;

In this example, we enable IDENTITY_INSERT for the tbl_content table, insert an explicit value into the id column, and then disable IDENTITY_INSERT.

Important Considerations

When using IDENTITY_INSERT, there are several important considerations to keep in mind:

• Only one table can have IDENTITY_INSERT enabled at a time. If you need to insert explicit values into multiple tables, you must enable IDENTITY_INSERT for each table separately.
• When IDENTITY_INSERT is enabled, the identity column is not automatically incremented. You must specify the value for the identity column in the INSERT statement.
• After inserting explicit values, it’s essential to disable IDENTITY_INSERT to prevent accidental insertion of duplicate or invalid values.

Using IDENTITY_INSERT in Stored Procedures

When using IDENTITY_INSERT in stored procedures, you should enable and disable it within the procedure itself. This ensures that IDENTITY_INSERT is only enabled for the duration of the procedure execution.

CREATE PROCEDURE spInsertDeletedIntoTBLContent
AS
BEGIN
    SET IDENTITY_INSERT tbl_content ON;

    INSERT INTO tbl_content (id, column1, column2)
    VALUES (1, 'value1', 'value2');

    SET IDENTITY_INSERT tbl_content OFF;
END;

In this example, the stored procedure enables IDENTITY_INSERT, inserts an explicit value into the id column, and then disables IDENTITY_INSERT.

Conclusion

Enabling explicit identity column insertion in SQL Server can be useful in various scenarios. By using the IDENTITY_INSERT property, you can insert specific values into identity columns while maintaining data integrity. Remember to enable and disable IDENTITY_INSERT carefully, considering the important considerations mentioned earlier.

By following the guidelines outlined in this tutorial, you can effectively use IDENTITY_INSERT to manage your database data and ensure accurate and consistent results.