What is the best approach to remove IDENTITY from a SQL Server table which already has data in it? Should I drop the table & create it again?
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You can just drop the identity column from the table:
ALTER TABLE dbo.table_name DROP COLUMN id;
There are a lot of questions around this seemingly simple question...
- Is the IDENTITY column the PK of the table?
- If the answer to #1 is "No", do you need to keep the numeric values of that column for ANY reason?
- If the answer to #1 is "Yes", you need to find all the FK's and other references that point to this column so that you can rebuild all of those after you build a new column, which ultimately should be named the same, which causes other complications that have some pretty easy work arounds.
Yes, IDENTITY column is the PK of the table for every table in my database.
I don't want PK to be removed, only IDENTITY to be removed.
Since these tables have some existing data in it & some tables have FK with other tables, it is causing some difficulty.
I can remove the IDENTITY in Dev server DB, just by going to design in SSMS & remove IDENTITY.
I want to remove it from Production server DB, through some scripts, which I don't have access to do it through design in SSMS.
I need a help on this part.
I am using the following query to remove the IDENTITY in tables where data already exists. This query works when there is no FK reference. When there is a FK reference it does not work. For example, the DeptD is referenced by another table having data, the following query does not work. Please let me know what I can do on this so that it will work for table having FK reference also.
BEGIN TRANSACTION SET QUOTED_IDENTIFIER ON SET ARITHABORT ON SET NUMERIC_ROUNDABORT OFF SET CONCAT_NULL_YIELDS_NULL ON SET ANSI_NULLS ON SET ANSI_PADDING ON SET ANSI_WARNINGS ON COMMIT BEGIN TRANSACTION GO USE RegTracInt CREATE TABLE [dbo].[TMP_DepartmentMaster]( [DEPTID] [bigint] NOT NULL, [DEPTCode] [nvarchar](50) NULL, [Name] [nvarchar](125) NULL, [Description] [nvarchar](500) NULL, [IsActive] [bit] NULL, [IsDeleted] [bit] NULL, [CreatedDate] [datetime] NULL, [CreatedBy] [nvarchar](256) NULL, [LastUpdatedDate] [datetime] NULL, [LastUpdatedBy] [nvarchar](256) NULL ) GO ---------------------------------- IF EXISTS(SELECT * FROM dbo.DepartmentMaster) EXEC('INSERT INTO dbo.TMP_DepartmentMaster ([DEPTID] ,[DEPTCode] ,[Name] ,[Description] ,[IsActive] ,[IsDeleted] ,[CreatedDate] ,[CreatedBy] ,[LastUpdatedDate] ,[LastUpdatedBy]) SELECT [DEPTID] ,[DEPTCode] ,[Name] ,[Description] ,[IsActive] ,[IsDeleted] ,[CreatedDate] ,[CreatedBy] ,[LastUpdatedDate] ,[LastUpdatedBy] FROM [dbo].[DepartmentMaster] WITH (HOLDLOCK TABLOCKX)') GO DROP TABLE dbo.DepartmentMaster GO EXECUTE sp_rename N'dbo.TMP_DepartmentMaster', N'DepartmentMaster', 'OBJECT' GO COMMIT ALTER TABLE [dbo].[DepartmentMaster] ADD CONSTRAINT [PK_DepartmentMaster] PRIMARY KEY CLUSTERED ( [DEPTID] ASC ) WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ALTER TABLE [dbo].[DepartmentMaster] ADD CONSTRAINT [DF_DepartmentMaster_IsActive] DEFAULT ((1)) FOR [IsActive] GO ALTER TABLE [dbo].[DepartmentMaster] ADD CONSTRAINT [DF_DepartmentMaster_IsDeleted] DEFAULT ((0)) FOR [IsDeleted] GO ALTER TABLE [dbo].[DepartmentMaster] ADD CONSTRAINT [DF_DepartmentMaster_CreatedDate] DEFAULT (getdate()) FOR [CreatedDate] GO ALTER TABLE [dbo].[DepartmentMaster] ADD CONSTRAINT [DF_DepartmentMaster_LastUpdatedDate] DEFAULT (getdate()) FOR [LastUpdatedDate] GO
To do this - you need to drop/remove all of the foreign keys on all tables that reference this table, then you can remove the IDENTITY - or rather, you can build a new table without the identity, copy the data - rename the table and rebuild the foreign keys.
Is there a specific reason you need to remove the identity? Has all the code that inserts data into this table been updated to generate the 'identity' value manually?
Just to be a bit pedantic, I don't believe you need to actually drop them or remove them (The FK constraints).. They can "just" be disabled and then re-enable when done.