SQL SERVER – Generate Foreign Key Scripts For Database

Regular reader of SQLAuthority.com blog Madhaiyan Seenivasan has send email with one very interesting script. This script generates all the foreign key addition script for your database. Many times there are situations where one need to drop all the foreign key and add them back. This SQL Script can be used for the same purpose.

You can execute the SP by executing its name like

EXEC DBO.SPGetForeignKeyInfo
IF EXISTS (
SELECT *
FROM dbo.sysobjects
WHERE id = OBJECT_ID(N'[dbo].[SPGetForeignKeyInfo]')
AND OBJECTPROPERTY(id, N'IsProcedure') = 1)
DROP PROCEDURE dbo.SPGetForeignKeyInfo
GO
CREATE PROCEDURE DBO.SPGetForeignKeyInfo
AS
/*
Author : Seenivasan
This procedure is used for Generating Foreign Key script.
*/
SET NOCOUNT ON
DECLARE @FKName NVARCHAR(128)
DECLARE @FKColumnName NVARCHAR(128)
DECLARE @PKColumnName NVARCHAR(128)
DECLARE @fTableName NVARCHAR(128)
DECLARE @fUpdateRule INT
DECLARE @fDeleteRule INT
DECLARE @FieldNames NVARCHAR(500)
CREATE TABLE #Temp(
PKTABLE_QUALIFIER NVARCHAR(128),
PKTABLE_OWNER NVARCHAR(128),
PKTABLE_NAME NVARCHAR(128),
PKCOLUMN_NAME NVARCHAR(128),
FKTABLE_QUALIFIER NVARCHAR(128),
FKTABLE_OWNER NVARCHAR(128),
FKTABLE_NAME NVARCHAR(128),
FKCOLUMN_NAME NVARCHAR(128),
KEY_SEQ INT,
UPDATE_RULE INT,
DELETE_RULE INT,
FK_NAME NVARCHAR(128),
PK_NAME NVARCHAR(128),
DEFERRABILITY INT)
DECLARE TTableNames CURSOR FOR
SELECT name
FROM sysobjects
WHERE xtype = 'U'
OPEN TTableNames
FETCH NEXT
FROM TTableNames
INTO @fTableName
WHILE @@FETCH_STATUS = 0
BEGIN
INSERT #Temp
EXEC dbo.sp_fkeys @fTableName
FETCH NEXT
FROM TTableNames
INTO @fTableName
END
CLOSE TTableNames
DEALLOCATE TTableNames
SET @FieldNames = ''
SET @fTableName = ''
SELECT DISTINCT FK_NAME AS FKName,FKTABLE_NAME AS FTName,
@FieldNames AS FTFields,PKTABLE_NAME AS STName,
@FieldNames AS STFields,@FieldNames AS FKType
INTO #Temp1
FROM #Temp
ORDER BY FK_NAME,FKTABLE_NAME,PKTABLE_NAME
DECLARE FK_CUSROR CURSOR FOR
SELECT FKName
FROM #Temp1
OPEN FK_CUSROR
FETCH
FROM FK_CUSROR INTO @FKName
WHILE @@FETCH_STATUS = 0
BEGIN
DECLARE FK_FIELDS_CUSROR CURSOR FOR
SELECT FKCOLUMN_NAME,PKCOLUMN_NAME,UPDATE_RULE,DELETE_RULE
FROM #TEMP
WHERE FK_NAME = @FKName
ORDER BY KEY_SEQ
OPEN FK_FIELDS_CUSROR
FETCH
FROM FK_FIELDS_CUSROR INTO @FKColumnName,@PKColumnName,
@fUpdateRule,@fDeleteRule
WHILE @@FETCH_STATUS = 0
BEGIN
UPDATE #Temp1 SET FTFields = CASE WHEN LEN(FTFields)
= 0 THEN '['+@FKColumnName+']'
ELSE FTFields
+',['+@FKColumnName+']' END
WHERE FKName = @FKName
UPDATE #Temp1 SET STFields = CASE WHEN LEN(STFields)
= 0 THEN '['+@PKColumnName+']'
ELSE STFields
+',['+@PKColumnName+']' END
WHERE FKName = @FKName
FETCH NEXT
FROM FK_FIELDS_CUSROR INTO @FKColumnName,@PKColumnName,
@fUpdateRule,@fDeleteRule
END
UPDATE #Temp1 SET FKType = CASE WHEN @fUpdateRule = 0
THEN FKType + ' ON UPDATE CASCADE'
ELSE FKType END
WHERE FKName = @FKName
UPDATE #Temp1 SET FKType = CASE WHEN @fDeleteRule = 0
THEN FKType + ' ON DELETE CASCADE'
ELSE FKType END
WHERE FKName = @FKName
CLOSE FK_FIELDS_CUSROR
DEALLOCATE FK_FIELDS_CUSROR
FETCH next
FROM FK_CUSROR INTO @FKName
END
CLOSE FK_CUSROR
DEALLOCATE FK_CUSROR
SELECT 'ALTER TABLE [dbo].['+FTName+'] ADD
CONSTRAINT ['+FKName+'] FOREIGN KEY ('+FTFields+')
REFERENCES ['+STName+'] ('+STFields+') '+FKType
FROM #Temp1
SET NOCOUNT OFF
RETURN
GO


Reference : Pinal Dave (https://darkslategrey-bat-805937.hostingersite.com) , Madhaiyan Seenivasan