Reseeding SQL Table Primary Key - SQL

Introduction

In SQL, a table's primary key is used to uniquely identify each row in the table. When a table's data is deleted or truncated, its primary key value will start from its current maximum value. This may result in gaps in the primary key value sequence, which can cause issues when using the primary key value for referencing the table's data. To fix this issue, a process called "Reseeding" can be used to reset the primary key value to a specified starting value.

Reseeding Process

Syntax

The SQL syntax for rescaling a table's primary key is as follows:

DBCC CHECKIDENT (table_name, RESEED, new_start_value)

Parameters

• table_name: The name of the table that you want to reseed.
• new_start_value: The new value that you want to set as the starting value for the table's primary key.

Example

Suppose you have a table named "Employees" and its primary key column is "EmployeeID". If you want to reseed the table's primary key to start from "1001", you can use the following SQL command:

DBCC CHECKIDENT (Employees, RESEED, 1001);

Conclusion

Reseeding a SQL table's primary key can help ensure that the primary key values are not duplicated or have gaps, making it easier to reference the table's data. It is a simple process that can be executed via a single SQL command.