Generating Foreign Key Definition of Database

Introduction

All the DB Developer are like to use DB Diagram to design Database. They used drag and drop process to make the Foreign key references between the table. Quite easy… is it?

But the real problem is that when we are trying to generate the foreign key definition (Script) to deploy it in the Production DB. There is no shortcut method to get the definition of foreign key in entire DB. We can list the entire foreign key in a DB but not get the definition all together.

In this article I we are trying to create a Script which can generate the definition of the entire foreign key in the Database.

Hope you will find it informative.

To list all the Foreign key Constraint in Database

SELECT RC.CONSTRAINT_NAME FK_Name, KF.TABLE_SCHEMA FK_Schema,

       KF.TABLE_NAME FK_Table, KF.COLUMN_NAME FK_Column,

       RC.UNIQUE_CONSTRAINT_NAME PK_Name, KP.TABLE_SCHEMA PK_Schema,

       KP.TABLE_NAME PK_Table, KP.COLUMN_NAME PK_Column,

       RC.MATCH_OPTION MatchOption, RC.UPDATE_RULE UpdateRule,

       RC.DELETE_RULE DeleteRule

FROM    INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS RC

        INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE KF

                         ON RC.CONSTRAINT_NAME = KF.CONSTRAINT_NAME

        INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE KP

                         ON RC.UNIQUE_CONSTRAINT_NAME = KP.CONSTRAINT_NAME;

By this script we can list all the Foreign key and their related table objects.

Create Script

Now we are creating a Stored Procedure to generate the Definition of Foreign key constraint

BEGIN

    DECLARE @v_FK_Name     VARCHAR(Max),

            @v_FK_Schema    VARCHAR(Max),

            @v_FK_Table     VARCHAR(Max),

            @v_FK_Column    VARCHAR(Max),

            @v_PK_Name      VARCHAR(Max),

            @v_PK_Schema    VARCHAR(Max),

            @v_PK_Table     VARCHAR(Max),

            @v_PK_Column    VARCHAR(Max),

            @v_MatchOption  VARCHAR(Max),

            @v_UpdateRule   VARCHAR(Max),

            @v_DeleteRule   VARCHAR(Max);

                    

    DECLARE @v_TotalRecords BIGINT,

            @v_StartRecords BIGINT;

    DECLARE @v_SQLScript   VARCHAR(Max);

      

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

          DROP TABLE #temp_FKDefination;

    CREATE TABLE #temp_FKDefination

        (

            Defination            VARCHAR(Max)

        );

                                          

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

          DROP TABLE #tbl_FK;

    SELECT    ROW_NUMBER() OVER(ORDER BY  RC.CONSTRAINT_NAME) AS SrlNo,

              RC.CONSTRAINT_NAME FK_Name, KF.TABLE_SCHEMA FK_Schema,

              KF.TABLE_NAME FK_Table, KF.COLUMN_NAME FK_Column,

              RC.UNIQUE_CONSTRAINT_NAME PK_Name, KP.TABLE_SCHEMA PK_Schema,

              KP.TABLE_NAME PK_Table, KP.COLUMN_NAME PK_Column,

              RC.MATCH_OPTION MatchOption, RC.UPDATE_RULE UpdateRule,

              RC.DELETE_RULE DeleteRule

    INTO    #tbl_FK

    FROM    INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS RC

            INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE KF

                        ON RC.CONSTRAINT_NAME = KF.CONSTRAINT_NAME

            INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE KP

                        ON RC.UNIQUE_CONSTRAINT_NAME = KP.CONSTRAINT_NAME;

    SET  @v_TotalRecords = (SELECT COUNT(*) FROM #tbl_FK);

    SET  @v_StartRecords = 1;

    WHILE @v_StartRecords <=  @v_TotalRecords

         BEGIN

             SELECT  @v_FK_Name = FK_Name,

                     @v_FK_Schema = FK_Schema,

                     @v_FK_Table = FK_Table,

                     @v_FK_Column = FK_Column,

                     @v_PK_Name = PK_Name,

                     @v_PK_Schema = PK_Schema,

                     @v_PK_Table = PK_Table,

                     @v_PK_Column = PK_Column,

                     @v_MatchOption = MatchOption,

                     @v_UpdateRule = UpdateRule,

                     @v_DeleteRule = DeleteRule

              FROM    #tbl_FK

              WHERE   SrlNo = @v_StartRecords;

      

       SET @v_SQLScript = '';

              SET @v_SQLScript = 'ALTER TABLE ['+ @v_FK_Schema +'].[' + @v_FK_Table +']'; 

               SET @v_SQLScript = @v_SQLScript + ' WITH NOCHECK ADD  CONSTRAINT ['+ @v_FK_Name +']';

              SET @v_SQLScript = @v_SQLScript + ' FOREIGN KEY(['+ @v_FK_Column +'])';

              SET @v_SQLScript = @v_SQLScript + ' REFERENCES ['+ @v_PK_Schema +'].[' + @v_PK_Table +']';

              SET @v_SQLScript = @v_SQLScript + ' (['+ @v_PK_Column +'])';

                 

               INSERT INTO #temp_FKDefination (Defination)

              VALUES ( @v_SQLScript );

              SET @v_SQLScript = 'ALTER TABLE ['+ @v_FK_Schema +'].[' + @v_FK_Table +']';

              SET @v_SQLScript = @v_SQLScript + ' CHECK CONSTRAINT ['+ @v_FK_Name +']'

              INSERT INTO #temp_FKDefination (Defination)

              VALUES ( @v_SQLScript );

              SET  @v_StartRecords = @v_StartRecords + 1;

        END

         SELECT * FROM #temp_FKDefination;

END

GO

Output is:

Analyze the Output

If we analyze the output we find

ALTER TABLE [dbo].[CancerHistory] WITH NOCHECK

ADD  CONSTRAINT [FK_CancerHistory_MasterSystemSiteOfRadiationTherapy]

FOREIGN KEY([idSiteOfRadiationTherapy])

REFERENCES [dbo].[MasterSystemSiteOfRadiationTherapy] ([idSiteOfRadiationTherapy]);

ALTER TABLE [dbo].[CancerHistory]

CHECK CONSTRAINT [FK_CancerHistory_MasterSystemSiteOfRadiationTherapy];

Hope you like it.

Posted By: JOYDEEP DAS