Change the table field to the auto-increment ID in SQL

The following is an SQL statement:

-- Delete the primary key constraint
Declare
@ Constraint_nameVarchar(200)
Select
@ Constraint_name= NameFromDBO. sysobjects

WhereXtype = 'pk'
AndParent_obj =

(Select[ID]
FromDBO. sysobjects

WhereId = object_id (n '[Table Name] ')

AndObjectproperty (ID, N 'isusertable') = 1)

If @ Constraint_name<>''
Begin
ALTER TABLE Table Name
Drop Constraint
@ Constraint_name
End
-- Delete the primary key field

Declare
@ CountInt

Select@ Count= Count (*)
FromSysobjects A, syscolumns B

WhereA. ID = B. ID and B. Name ='Primary key field name'And A. Name ='Table Name'
If@ Count> 0
Begin
ALTER TABLE Table Name
Drop Column Primary key field name
End

-- Create a field, primary key, and auto-Increment
ALTER TABLE Table NameAdd
Primary key field name Int identity(1, 1)Primary Key