tmap cross join question

Five Stars

tmap cross join question

thumbnail_IMG_9394 (1).jpg

 

From the screenshot i don't see any link between row1 and row2 in tmap. what kind of join is this? so far I saw a join condition(inner join) and a link. In this case it says left outer join but on what condition is the big question. From what i see my data does  not match on those columns. Even if this is a cross join there should be a matching condition but in this case there is none. I am having hard time trying to decode this to Sql. Any help on this is greatly appreciated. 


Accepted Solutions
Nine Stars

Re: tmap cross join question

Hi,

 

Its giving you the Cartesian product of both sources. The "Left outer join" is part of the join model, which you have no join, so is somewhat obsolete. For each individual flow in row1.....every entry in row2 will be matched.

 

Regards David
Dont forget to give Kudos when an answer is helpful or mark the answer as the solution.

View solution in original post


All Replies
Nine Stars

Re: tmap cross join question

Hi,

 

Its giving you the Cartesian product of both sources. The "Left outer join" is part of the join model, which you have no join, so is somewhat obsolete. For each individual flow in row1.....every entry in row2 will be matched.

 

Regards David
Dont forget to give Kudos when an answer is helpful or mark the answer as the solution.

View solution in original post

Five Stars

Re: tmap cross join question

Thank you very much. This helps. 

Community Manager

Re: tmap cross join question

A tMap is driven by one input source, the main source. In your case that is row1. Any other source is just for lookups. If you are not joining, then you will get every row of the lookup "matched" against every row of the main IF "Match Model" is set to "All rows". What you have there does look like a cross-join. You do not need a join condition on a cross-join as it is the Cartesian product.

Highlighted
Community Manager

Re: tmap cross join question

Sorry @david_beaty, it appears I started my response before you started yours and then got involved in something else before posting :-) Nice answer

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