Identity field fix

I inherited a system with a SQL 2000 DB. We discovered an identity field named barcode with some values that are incorrect. About 1000 of the records contain a barcode field with 13 digits, not forteen as required. This field is a standalone field only used on an ID card. I would like to select those 1000 records and update the barcode field to 14 digits. Is there an easy way to do this? Thx

First, check for tables with a Foreign key relationship to the table under consideration.

In each of the tables with a FK, set the table to CASCADE UPDATES for the FK field.

Then set IDENTITY INSERT ON for the primary table. [ SET IDENTITY INSERT MyTable ON ]

When you complete the corrections, set the IDENTITY INSERT off, and remove the CASCADE UPDATES on the FK fields.

Any other tables that also may have the values from the primary table will have to be manually discovered and corrected.

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Hi Arnie

Surely you'd have to remove the IDENTITY property from the column before performing any updates?

The example below doesn't allow updates to an IDENTITY column, failing with the following error:

Msg 8102, Level 16, State 1, Line 3

Cannot update identity column 'ID'.

Thanks
Chris

USE [tempdb]

GO

CREATE TABLE dbo.Test

(

ID INT IDENTITY NOT NULL,

MyField VARCHAR(9)

)

INSERT INTO dbo.Test (MyField)

VALUES ('TestValue')

SET IDENTITY_INSERT dbo.Test ON

UPDATE dbo.Test

SET ID = 2

SET IDENTITY_INSERT dbo.Test OFF

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Thanks Chris for catching that (posted before coffee...)

I left out that for this approach to work, it will be necessary to move all of the rows to be updated to a temp table, delete them from the primary table, add another column to the temp table, make the updates to the new column, then with IDENTITY_INSERT ON, add those columns back to the primary table -specifying the new column in place of the original ID column.

IF there were secondary tables with FK relationships, use the temp table to update the FK column in the secondary tables.

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Thx, for the suggestions. How about this senario:

I made a Test copy of the DB using the SQL Wizard Export. The Test DB did not contain the Identity property on the Barcode field like the LIVE DB and thus allows me to run a fix for the 1000 records that have a bad barcode field. Once fixed I am thinking of renaming the Test DB to LIVE.

I think Something like the following will solve the problem:

Update Person

Set Barcode = (Barcode + 1000000)

where Barcode < 3001000 (this identitfies the 1000 bad records)

TIA

Identity field fix

I inherited a system with a SQL 2000 DB. We discovered an identity field named barcode with some values that are incorrect. About 1000 of the records contain a barcode field with 13 digits, not forteen as required. This field is a standalone field only used on an ID card. I would like to select those 1000 records and update the barcode field to 14 digits. Is there an easy way to do this? Thx

First, check for tables with a Foreign key relationship to the table under consideration.

In each of the tables with a FK, set the table to CASCADE UPDATES for the FK field.

Then set IDENTITY INSERT ON for the primary table. [ SET IDENTITY INSERT MyTable ON ]

When you complete the corrections, set the IDENTITY INSERT off, and remove the CASCADE UPDATES on the FK fields.

Any other tables that also may have the values from the primary table will have to be manually discovered and corrected.

|||

Hi Arnie

Surely you'd have to remove the IDENTITY property from the column before performing any updates?

The example below doesn't allow updates to an IDENTITY column, failing with the following error:

Msg 8102, Level 16, State 1, Line 3

Cannot update identity column 'ID'.

Thanks
Chris

USE [tempdb]

GO

CREATE TABLE dbo.Test

(

ID INT IDENTITY NOT NULL,

MyField VARCHAR(9)

)

INSERT INTO dbo.Test (MyField)

VALUES ('TestValue')

SET IDENTITY_INSERT dbo.Test ON

UPDATE dbo.Test

SET ID = 2

SET IDENTITY_INSERT dbo.Test OFF

|||

Thanks Chris for catching that (posted before coffee...)

I left out that for this approach to work, it will be necessary to move all of the rows to be updated to a temp table, delete them from the primary table, add another column to the temp table, make the updates to the new column, then with IDENTITY_INSERT ON, add those columns back to the primary table -specifying the new column in place of the original ID column.

IF there were secondary tables with FK relationships, use the temp table to update the FK column in the secondary tables.

|||

Thx, for the suggestions. How about this senario:

I made a Test copy of the DB using the SQL Wizard Export. The Test DB did not contain the Identity property on the Barcode field like the LIVE DB and thus allows me to run a fix for the 1000 records that have a bad barcode field. Once fixed I am thinking of renaming the Test DB to LIVE.

I think Something like the following will solve the problem:

Update Person

Set Barcode = (Barcode + 1000000)

where Barcode < 3001000 (this identitfies the 1000 bad records)

TIA

Identity Column Fix

Hello, I am new to SQL and inhereted a system with a corrupt table. About 1000 records have an invalid barcode field which is an identity column and does not allow me to update once set. I need to fix these 1000 records by changing the field to 14 digits instead of the incorrect 13. What are some of my options? I was thinking about making a copy of the DB using the Wizzard, then turning the identity feature OFF and doing the fix using command SQL, then turning it back on and copying the DB back to production.

Any suggestions ? Thx

Copying the entire database seems like overkill for just 1000 rows. I've briefly put together an example below that shows how you can copy the data to a staging table, modify the data, then copy it back into your original table. Hope you find this useful.

Be aware that Foreign Key constraints could prevent you deleting rows from the main table. You'd have to drop the constraints then cascade the changes through to any referencing tables before re-applying the constraints. You'll have to do this regardless of the correction method chosen.

Chris

IF OBJECT_ID('tempdb..#MyTable') IS NOT NULL

DROP TABLE #MyTable

IF OBJECT_ID('tempdb..#StagingTable') IS NOT NULL

DROP TABLE #StagingTable

CREATE TABLE #MyTable

(ID INT IDENTITY PRIMARY KEY NOT NULL, MyColumn VARCHAR(10))

--Create a copy of the main table - note absence of the IDENTITY property

CREATE TABLE #StagingTable

(ID INT PRIMARY KEY NOT NULL, MyColumn VARCHAR(10))

--Set up test data

INSERT INTO #MyTable(MyColumn) VALUES('Test')

SELECT [ID], MyColumn

FROM #MyTable

--Copy the rogue data to the staging table

INSERT INTO #StagingTable([ID], MyColumn)

SELECT [ID], MyColumn

FROM #MyTable

WHERE [ID] = 1

--Correct the data in the staging table

UPDATE #StagingTable

SET [ID] = 2

--Delete the rogue data from the main table

DELETE FROM #MyTable

WHERE [ID] = 1

--Copy the corrected data to the production table

SET IDENTITY_INSERT #MyTable ON

INSERT INTO #MyTable([ID], MyColumn)

SELECT [ID], MyColumn

FROM #StagingTable

SET IDENTITY_INSERT #MyTable OFF

SELECT [ID], MyColumn

FROM #MyTable

|||

Identity Column Fix

Hello, I am new to SQL and inhereted a system with a corrupt table. About 1000 records have an invalid barcode field which is an identity column and does not allow me to update once set. I need to fix these 1000 records by changing the field to 14 digits instead of the incorrect 13. What are some of my options? I was thinking about making a copy of the DB using the Wizzard, then turning the identity feature OFF and doing the fix using command SQL, then turning it back on and copying the DB back to production.

Any suggestions ? Thx

Copying the entire database seems like overkill for just 1000 rows. I've briefly put together an example below that shows how you can copy the data to a staging table, modify the data, then copy it back into your original table. Hope you find this useful.

Be aware that Foreign Key constraints could prevent you deleting rows from the main table. You'd have to drop the constraints then cascade the changes through to any referencing tables before re-applying the constraints. You'll have to do this regardless of the correction method chosen.

Chris

IF OBJECT_ID('tempdb..#MyTable') IS NOT NULL

DROP TABLE #MyTable

IF OBJECT_ID('tempdb..#StagingTable') IS NOT NULL

DROP TABLE #StagingTable

CREATE TABLE #MyTable

(ID INT IDENTITY PRIMARY KEY NOT NULL, MyColumn VARCHAR(10))

--Create a copy of the main table - note absence of the IDENTITY property

CREATE TABLE #StagingTable

(ID INT PRIMARY KEY NOT NULL, MyColumn VARCHAR(10))

--Set up test data

INSERT INTO #MyTable(MyColumn) VALUES('Test')

SELECT [ID], MyColumn

FROM #MyTable

--Copy the rogue data to the staging table

INSERT INTO #StagingTable([ID], MyColumn)

SELECT [ID], MyColumn

FROM #MyTable

WHERE [ID] = 1

--Correct the data in the staging table

UPDATE #StagingTable

SET [ID] = 2

--Delete the rogue data from the main table

DELETE FROM #MyTable

WHERE [ID] = 1

--Copy the corrected data to the production table

SET IDENTITY_INSERT #MyTable ON

INSERT INTO #MyTable([ID], MyColumn)

SELECT [ID], MyColumn

FROM #StagingTable

SET IDENTITY_INSERT #MyTable OFF

SELECT [ID], MyColumn

FROM #MyTable

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