foreign key

i want to make primary key and foreign key relationship of table A1 and table B1 but A1 exist in database A and B1 exist in database B
column name u can pretain as C1, C2

'Normally', related tables live within the same database.

The Foreign Key constraint declaration doesn't go outside the scope of the database, so in this case you can't declare a FK constraint.

AFAIK, the option you have to enforce cross-database FK relationships, is by using triggers.

/Kenneth

|||

You can’t create a constraint across the database. But there is a workaround available to fix your issue. Using Instead of trigger / for after trigger. But I recommend to use the Instead of Trigger rather than after trigger..

Code Snippet

Use DB1

Go

Create table A

(

ID int Primary Key,

Name varchar(100)

)

Go

Code Snippet

Use DB2

Go

Create table BB

(

Id int,

[Desc] varchar(100)

)

Go

CreateTrigger BB_Triger

on BBInstead of Insert

as

Begin

Insert Into BB

Select * from Inserted as ins Where Exists (Select 1 From DB1..A a Where a.id = ins.id)

End

/*

--use any one

Create Trigger BB_Triger

on BBAfter Insert

as

Begin

Delete from BB

Where NOT EXISTS (Select 1 From DB1..A a Where a.id = BB.id)

End

*/

GO

Code Snippet

Insert Into DB1..A values(1,'One')

Insert Into DB2..A values(2,'Two')

Code Snippet

Insert Into DB2..BB values(1,'Valid')

select * from BB

Insert Into DB2..BB values(4,'In Valid')

select * from BB

|||Thanks good idea