Bulk modification of unique ids in SQL Server - sql-server

Question

[This is a bit of an unusual problem, I know...]
What I need is a script that will change every unique id value to new one in our database. The problem is that we have configuration tables that can be exported between instances of our software which is id-sensitive (clobbering existing ids). Years ago, we set up a "wide-enough" id gap between our development "standard configuration" and our client's instances, which is now not wide enough :( - e.g. we're getting id conflicts when clients import our standard configuration.
A SQL script to do the following is definitely the simplest/shortest-timeframe thing that we can do. e.g. fixing the code is far too complicated and error prone to consider. Note that we are not "eliminating" the problem here. Just changing the gap from 1000's to 1000000's or more (the existing gap took 5 years to fill).
I believe the simplest solution would be to:
change all our tables to UPDATE_CASCADE (none of them are - this will greatly simplify the script)
create an identity table with the new lowest id that we want
For each table, modify the id to the next one in the identity table (using identity insert modifier flags where necessary). Perhaps after each table is processed, we could reset the identity table.
turn off UPDATE_CASCADE, and delete the identity table.
I am seeking any (partial or full) scripts for this.

Answer 1

Unfortunately UPDATE_CASCADE doesn't exist in the world of Sql Server. I suggest for each table you to re-key you do the following (Pseudo Code)
BACKUP DATABASE
CHECK BACKUP WORKS!
FOR EACH TABLE TO BE RE-KEYED
DROP ALL FOREIGN KEY CONSTRAINTS, INDEXES ETC FROM TABLE
SELECT ID + Number, ALL_OTHER_FIELDS INTO TEMP_TABLE FROM TABLE
RENAME TABLE OLD_TABLE
RENAME TEMP_TABLE TABLE
FOR ALL TABLES REFERENCING THIS TABLE
UPDATE FOREIGN_KEY_TABLE SET FK_ID = FK_ID + new number
END FOR
RE-APPLY FOREIGN KEY CONSTRAINTS, INDEXES ETC FROM TABLE
END FOR
Check it all still works ...
This process could be automated through DMO/SMO objects, but depending on the number of tables involved I'd say using management studio to generate scripts that can then be edited is probably quicker. After all, you only need to do this once/5 years.

Answer 2

Here we go with the code for SQL 2005. It's huge, it's hacky, but it will work (except in the case where you have a primary key that is a composite of two other primary keys).
If someone can re-write this with MrTelly's faster id addition (which wouldn't require building sql from a cursor for each updated row), then I'll mark that as the accepted answer. (If I don't notice the new answer, upvote this - then I'll notice :))
BEGIN TRAN
SET NOCOUNT ON;
DECLARE #newLowId INT
SET #newLowId = 1000000
DECLARE #sql VARCHAR(4000)
--**** SELECT ALL TABLES WITH IDENTITY COLUMNS ****
DECLARE tables SCROLL CURSOR
FOR
SELECT '[' + SCHEMA_NAME(schema_id) + '].[' + t.name + ']', c.name
FROM sys.identity_columns c
INNER JOIN sys.objects t
on c.object_id = t.object_id
WHERE t.type_Desc = 'USER_TABLE'
OPEN tables
DECLARE #Table VARCHAR(100)
DECLARE #IdColumn VARCHAR(100)
CREATE Table #IdTable(
id INT IDENTITY(1,1),
s CHAR(1)
)
FETCH FIRST FROM tables
INTO #Table, #IdColumn
WHILE ##FETCH_STATUS = 0
BEGIN
PRINT('
****************** '+#Table+' ******************
')
--Reset the idtable to the 'low' id mark - remove this line if you want all records to have distinct ids across the database
DELETE FROM #IdTable
DBCC CHECKIDENT('#IdTable', RESEED, #newLowId)
--**** GENERATE COLUMN SQL (for inserts and deletes - updating identities is not allowed) ****
DECLARE tableColumns CURSOR FOR
SELECT column_name FROM information_schema.columns
WHERE '[' + table_schema + '].[' + table_name + ']' = #Table
AND column_name <> #IdColumn
OPEN tableColumns
DECLARE #columnName VARCHAR(100)
DECLARE #columns VARCHAR(4000)
SET #columns = ''
FETCH NEXT FROM tableColumns INTO #columnName
WHILE ##FETCH_STATUS = 0
BEGIN
SET #columns = #columns + #columnName
FETCH NEXT FROM tableColumns INTO #columnName
IF ##FETCH_STATUS = 0 SET #columns = #columns + ', '
END
CLOSE tableColumns
DEALLOCATE tableColumns
--**** GENERATE FOREIGN ROW UPDATE SQL ****
DECLARE foreignkeys SCROLL CURSOR
FOR
SELECT con.name,
'[' + SCHEMA_NAME(f.schema_id) + '].[' + f.name + ']' fTable, fc.column_name ,
'[' + SCHEMA_NAME(p.schema_id) + '].[' + p.name + ']' pTable, pc.column_name
FROM sys.foreign_keys con
INNER JOIN sysforeignkeys syscon
ON con.object_id = syscon.constid
INNER JOIN sys.objects f
ON con.parent_object_id = f.object_id
INNER JOIN information_schema.columns fc
ON fc.table_schema = SCHEMA_NAME(f.schema_id)
AND fc.table_name = f.name
AND fc.ordinal_position = syscon.fkey
INNER JOIN sys.objects p
ON con.referenced_object_id = p.object_id
INNER JOIN information_schema.columns pc
ON pc.table_schema = SCHEMA_NAME(p.schema_id)
AND pc.table_name = p.name
AND pc.ordinal_position = syscon.rkey
WHERE '[' + SCHEMA_NAME(p.schema_id) + '].[' + p.name + ']' = #Table
OPEN foreignkeys
DECLARE #FKeyName VARCHAR(100)
DECLARE #FTable VARCHAR(100)
DECLARE #FColumn VARCHAR(100)
DECLARE #PTable VARCHAR(100)
DECLARE #PColumn VARCHAR(100)
--**** RE-WRITE ALL IDS IN THE TABLE ****
SET #sql='DECLARE tablerows CURSOR FOR
SELECT CAST('+#IdColumn+' AS VARCHAR) FROM '+#Table+' ORDER BY '+#IdColumn
PRINT(#sql)
exec(#sql)
OPEN tablerows
DECLARE #rowid VARCHAR(100)
DECLARE #id VARCHAR(100)
FETCH NEXT FROM tablerows INTO #rowid
WHILE ##FETCH_STATUS = 0
BEGIN
--generate new id
INSERT INTO #IdTable VALUES ('')
SELECT #id = CAST(##IDENTITY AS VARCHAR)
IF #rowId <> #Id
BEGIN
PRINT('Modifying '+#Table+': changing '+#rowId+' to '+#id)
SET #sql='SET IDENTITY_INSERT ' + #Table + ' ON
INSERT INTO '+#Table+' ('+#IdColumn+','+#columns+') SELECT '+#id+','+#columns+' FROM '+#Table+' WHERE '+#IdColumn+'='+#rowId
--Updating all foreign rows...
FETCH FIRST FROM foreignkeys
INTO #FKeyName, #FTable, #FColumn, #PTable, #PColumn
WHILE ##FETCH_STATUS = 0
BEGIN
SET #sql = #sql + '
UPDATE '+#FTable+' SET '+#FColumn+'='+#id+' WHERE '+#FColumn+' ='+#rowId
FETCH NEXT FROM foreignkeys
INTO #FKeyName, #FTable, #FColumn, #PTable, #PColumn
END
SET #sql=#sql + '
DELETE FROM '+#Table+' WHERE '+#IdColumn+'='+#rowId
PRINT(#sql)
exec(#sql)
END
FETCH NEXT FROM tablerows INTO #rowid
END
CLOSE tablerows
DEALLOCATE tablerows
CLOSE foreignkeys
DEALLOCATE foreignkeys
--Revert to normal identity operation - update the identity to the latest id...
DBCC CHECKIDENT(#Table, RESEED, ##IDENTITY)
SET #sql='SET IDENTITY_INSERT ' + #Table + ' OFF'
PRINT(#sql)
exec(#sql)
FETCH NEXT FROM tables
INTO #Table, #IdColumn
END
CLOSE tables
DEALLOCATE tables
DROP TABLE #IdTable
--COMMIT
--ROLLBACK

Answer 3

Why don't you use negative numbers for your standard configuration values and continue to use positive numbers for other things?