Relation between tables in different databases using SQL Server 2005

is there any way t开发者_如何学运维o add a relation between 2 tables in different databases ?

For example:

db1.dbo.table1 field id = db2.dbo.table2 field id

the nearest thing that i´m looking for is something like:

CREATE TRIGGER RELATIONAL on IDCLIENT
FOR INSERT
As
   IF (SELECT COUNT(*) FROM table1) = 1
      INSERT INTO db2.dbo.table2(ID) 
          SELECT ID FROM table1

You can create a synonym for the other table in another db, and then you can reference it by its synonym name.