compare attributes of two different tables

I have two tables that are related through two attributes (Attribute A of table 1 and Attribute B of table 2). Now I would like set a new ID-Attribute (primary key) in table 1 and use this ID as the foreign key in table 2.

 

That means that I have to compare the attributes of the two tables and if attribute A of table 1 equals attribute B of table 2 then I write the ID-attribute of table 1 as FK to table 2.

 

I looked through the transformers but I couldn't find one where I was able two compare attributes of two different tables. But there sure is one...?!

 

 

Thanks in advance

 

Vera