Generate Delete Statement From Foreign Key Relationships in SQL 2008?
Here is a script for cascading delete by Aasim Abdullah, works for me on MS SQL Server 2008:
IF OBJECT_ID('dbo.udfGetFullQualName') IS NOT NULL
DROP FUNCTION dbo.udfGetFullQualName;
GO
CREATE FUNCTION dbo.udfGetFullQualName
(@ObjectId INT)
RETURNS VARCHAR (300)
AS
BEGIN
DECLARE @schema_id AS BIGINT;
SELECT @schema_id = schema_id
FROM sys.tables
WHERE object_id = @ObjectId;
RETURN '[' + SCHEMA_NAME(@schema_id) + '].[' + OBJECT_NAME(@ObjectId) + ']';
END
GO
--============ Supporting Function dbo.udfGetOnJoinClause
IF OBJECT_ID('dbo.udfGetOnJoinClause') IS NOT NULL
DROP FUNCTION dbo.udfGetOnJoinClause;
GO
CREATE FUNCTION dbo.udfGetOnJoinClause
(@fkNameId INT)
RETURNS VARCHAR (1000)
AS
BEGIN
DECLARE @OnClauseTemplate AS VARCHAR (1000);
SET @OnClauseTemplate = '[<@pTable>].[<@pCol>] = [<@cTable>].[<@cCol>] AND ';
DECLARE @str AS VARCHAR (1000);
SET @str = '';
SELECT @str = @str + REPLACE(REPLACE(REPLACE(REPLACE(@OnClauseTemplate, '<@pTable>', OBJECT_NAME(rkeyid)), '<@pCol>', COL_NAME(rkeyid, rkey)), '<@cTable>', OBJECT_NAME(fkeyid)), '<@cCol>', COL_NAME(fkeyid, fkey))
FROM dbo.sysforeignkeys AS fk
WHERE fk.constid = @fkNameId; --OBJECT_ID('FK_ProductArrearsMe_ProductArrears')
RETURN LEFT(@str, LEN(@str) - LEN(' AND '));
END
GO
--=========== CASECADE DELETE STORED PROCEDURE dbo.uspCascadeDelete
IF OBJECT_ID('dbo.uspCascadeDelete') IS NOT NULL
DROP PROCEDURE dbo.uspCascadeDelete;
GO
CREATE PROCEDURE dbo.uspCascadeDelete
@ParentTableId VARCHAR (300), @WhereClause VARCHAR (2000), @ExecuteDelete CHAR (1)='N', --'N' IF YOU NEED DELETE SCRIPT
@FromClause VARCHAR (8000)='', @Level INT=0 -- TABLE NAME OR OBJECT (TABLE) ID (Production.Location) WHERE CLAUSE (Location.LocationID = 7) 'Y' IF WANT TO DELETE DIRECTLY FROM SP, IF LEVEL 0, THEN KEEP DEFAULT
AS -- writen by Daniel Crowther 16 Dec 2004 - handles composite primary keys
SET NOCOUNT ON;
/* Set up debug */
DECLARE @DebugMsg AS VARCHAR (4000),
@DebugIndent AS VARCHAR (50);
SET @DebugIndent = REPLICATE('---', @@NESTLEVEL) + '> ';
IF ISNUMERIC(@ParentTableId) = 0
BEGIN -- assume owner is dbo and calculate id
IF CHARINDEX('.', @ParentTableId) = 0
SET @ParentTableId = OBJECT_ID('[dbo].[' + @ParentTableId + ']');
ELSE
SET @ParentTableId = OBJECT_ID(@ParentTableId);
END
IF @Level = 0
BEGIN
PRINT @DebugIndent + ' **************************************************************************';
PRINT @DebugIndent + ' *** Cascade delete ALL data from ' + dbo.udfGetFullQualName(@ParentTableId);
IF @ExecuteDelete = 'Y'
PRINT @DebugIndent + ' *** @ExecuteDelete = Y *** deleting data...';
ELSE
PRINT @DebugIndent + ' *** Cut and paste output into another window and execute ***';
END
DECLARE @CRLF AS CHAR (2);
SET @CRLF = CHAR(13) + CHAR(10);
DECLARE @strSQL AS VARCHAR (4000);
IF @Level = 0
SET @strSQL = 'SET NOCOUNT ON' + @CRLF;
ELSE
SET @strSQL = '';
SET @strSQL = @strSQL + 'PRINT ''' + @DebugIndent + dbo.udfGetFullQualName(@ParentTableId) + ' Level=' + CAST (@@NESTLEVEL AS VARCHAR) + '''';
IF @ExecuteDelete = 'Y'
EXECUTE (@strSQL);
ELSE
PRINT @strSQL;
DECLARE curs_children CURSOR LOCAL FORWARD_ONLY
FOR SELECT DISTINCT constid AS fkNameId, -- constraint name
fkeyid AS cTableId
FROM dbo.sysforeignkeys AS fk
WHERE fk.rkeyid <> fk.fkeyid -- WE DO NOT HANDLE self referencing tables!!!
AND fk.rkeyid = @ParentTableId;
OPEN curs_children;
DECLARE @fkNameId AS INT,
@cTableId AS INT,
@cColId AS INT,
@pTableId AS INT,
@pColId AS INT;
FETCH NEXT FROM curs_children INTO @fkNameId, @cTableId; --, @cColId, @pTableId, @pColId
DECLARE @strFromClause AS VARCHAR (1000);
DECLARE @nLevel AS INT;
IF @Level = 0
BEGIN
SET @FromClause = 'FROM ' + dbo.udfGetFullQualName(@ParentTableId);
END
WHILE @@FETCH_STATUS = 0
BEGIN
SELECT @strFromClause = @FromClause + @CRLF + ' INNER JOIN ' + dbo.udfGetFullQualName(@cTableId) + @CRLF + ' ON ' + dbo.udfGetOnJoinClause(@fkNameId);
SET @nLevel = @Level + 1;
EXECUTE dbo.uspCascadeDelete @ParentTableId = @cTableId, @WhereClause = @WhereClause, @ExecuteDelete = @ExecuteDelete, @FromClause = @strFromClause, @Level = @nLevel;
SET @strSQL = 'DELETE FROM ' + dbo.udfGetFullQualName(@cTableId) + @CRLF + @strFromClause + @CRLF + 'WHERE ' + @WhereClause + @CRLF;
SET @strSQL = @strSQL + 'PRINT ''---' + @DebugIndent + 'DELETE FROM ' + dbo.udfGetFullQualName(@cTableId) + ' Rows Deleted: '' + CAST(@@ROWCOUNT AS VARCHAR)' + @CRLF + @CRLF;
IF @ExecuteDelete = 'Y'
EXECUTE (@strSQL);
ELSE
PRINT @strSQL;
FETCH NEXT FROM curs_children INTO @fkNameId, @cTableId;
--, @cColId, @pTableId, @pColId
END
IF @Level = 0
BEGIN
SET @strSQL = @CRLF + 'PRINT ''' + @DebugIndent + dbo.udfGetFullQualName(@ParentTableId) + ' Level=' + CAST (@@NESTLEVEL AS VARCHAR) + ' TOP LEVEL PARENT TABLE''' + @CRLF;
SET @strSQL = @strSQL + 'DELETE FROM ' + dbo.udfGetFullQualName(@ParentTableId) + ' WHERE ' + @WhereClause + @CRLF;
SET @strSQL = @strSQL + 'PRINT ''' + @DebugIndent + 'DELETE FROM ' + dbo.udfGetFullQualName(@ParentTableId) + ' Rows Deleted: '' + CAST(@@ROWCOUNT AS VARCHAR)' + @CRLF;
IF @ExecuteDelete = 'Y'
EXECUTE (@strSQL);
ELSE
PRINT @strSQL;
END
CLOSE curs_children;
DEALLOCATE curs_children;
Usage example 1
Note the use of the fully qualified column name in the example. It's subtle but you must specify the table name for the generated SQL to execute properly.
EXEC uspCascadeDelete
@ParentTableId = 'Production.Location',
@WhereClause = 'Location.LocationID = 2'
Usage example 2
EXEC uspCascadeDelete
@ParentTableId = 'dbo.brand',
@WhereClause = 'brand.brand_name <> ''Apple'''
Usage example 3
exec uspCascadeDelete
@ParentTableId = 'dbo.product_type',
@WhereClause = 'product_type.product_type_id NOT IN
(SELECT bpt.product_type_id FROM dbo.brand_product_type bpt)'
DELETE statements generated for use in SP with parameter, and as ON DELETE triggers: (this variant supports single column FKs only)
SELECT 'DELETE '+detail.name+' WHERE '+dcolumn.name+' = @'+mcolumn.name AS stmt,
'DELETE ' + detail.name + ' FROM ' + detail.name + ' INNER JOIN deleted ON ' +
detail.name + '.' + dcolumn.name + ' = deleted.' + mcolumn.name AS trg
FROM sys.columns AS mcolumn
INNER JOIN sys.foreign_key_columns ON mcolumn.object_id =
sys.foreign_key_columns.referenced_object_id
AND mcolumn.column_id = sys.foreign_key_columns.referenced_column_id
INNER JOIN sys.tables AS master ON mcolumn.object_id = master.object_id
INNER JOIN sys.columns AS dcolumn
ON sys.foreign_key_columns.parent_object_id = dcolumn.object_id
AND sys.foreign_key_columns.parent_column_id = dcolumn.column_id
INNER JOIN sys.tables AS detail ON dcolumn.object_id = detail.object_id
WHERE (master.name = N'MyTableName')
I'm pretty sure I posted code here on Stack Overflow which does this automatically using INFORMATION_SCHEMA to generate dynamic SQL, but I can't find it. Let me see if I can regenerate it.
You might need to check this out a bit, I couldn't find my original code, so I modified some code I had which builds flattend views for star-schemas automatically.
DECLARE @COLUMN_NAME AS sysname
DECLARE @TABLE_NAME AS sysname
DECLARE @IDValue AS int
SET @COLUMN_NAME = '<Your COLUMN_NAME here>'
SET @TABLE_NAME = '<Your TABLE_NAME here>'
SET @IDValue = 123456789
DECLARE @sql AS varchar(max) ;
WITH RELATED_COLUMNS
AS (
SELECT QUOTENAME(c.TABLE_SCHEMA) + '.'
+ QUOTENAME(c.TABLE_NAME) AS [OBJECT_NAME]
,c.COLUMN_NAME
FROM INFORMATION_SCHEMA.COLUMNS AS c WITH (NOLOCK)
INNER JOIN INFORMATION_SCHEMA.TABLES AS t WITH (NOLOCK)
ON c.TABLE_CATALOG = t.TABLE_CATALOG
AND c.TABLE_SCHEMA = t.TABLE_SCHEMA
AND c.TABLE_NAME = t.TABLE_NAME
AND t.TABLE_TYPE = 'BASE TABLE'
INNER JOIN (
SELECT rc.CONSTRAINT_CATALOG
,rc.CONSTRAINT_SCHEMA
,lkc.TABLE_NAME
,lkc.COLUMN_NAME
FROM INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS rc
WITH (NOLOCK)
INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE lkc
WITH (NOLOCK)
ON lkc.CONSTRAINT_CATALOG = rc.CONSTRAINT_CATALOG
AND lkc.CONSTRAINT_SCHEMA = rc.CONSTRAINT_SCHEMA
AND lkc.CONSTRAINT_NAME = rc.CONSTRAINT_NAME
INNER JOIN INFORMATION_SCHEMA.TABLE_CONSTRAINTS tc
WITH (NOLOCK)
ON rc.CONSTRAINT_CATALOG = tc.CONSTRAINT_CATALOG
AND rc.CONSTRAINT_SCHEMA = tc.CONSTRAINT_SCHEMA
AND rc.UNIQUE_CONSTRAINT_NAME = tc.CONSTRAINT_NAME
INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE rkc
WITH (NOLOCK)
ON rkc.CONSTRAINT_CATALOG = tc.CONSTRAINT_CATALOG
AND rkc.CONSTRAINT_SCHEMA = tc.CONSTRAINT_SCHEMA
AND rkc.CONSTRAINT_NAME = tc.CONSTRAINT_NAME
WHERE rkc.COLUMN_NAME = @COLUMN_NAME
AND rkc.TABLE_NAME = @TABLE_NAME
) AS j
ON j.CONSTRAINT_CATALOG = c.TABLE_CATALOG
AND j.CONSTRAINT_SCHEMA = c.TABLE_SCHEMA
AND j.TABLE_NAME = c.TABLE_NAME
AND j.COLUMN_NAME = c.COLUMN_NAME
)
SELECT @sql = COALESCE(@sql, '') + 'DELETE FROM ' + [OBJECT_NAME]
+ ' WHERE ' + [COLUMN_NAME] + ' = ' + CONVERT(varchar, @IDValue)
+ CHAR(13) + CHAR(10)
FROM RELATED_COLUMNS
PRINT @sql
Another technique is to use a code generator to create the Sql. I'm pretty sure the MyGeneration (no connection) has existing templates to do this. Using that tool and the right template you can create a sql script that deletes the relevant stuff with no pain.