Forum Discussion
two both direction between two fact table and two dimension table
There are two dimension tables dim1,dim2, and two fact tables fact1,fact2
the model is dim1 has 1-n relation fact1 and fact2 with column col1,
and dim2 has 1-n relation fact1 and fact2 with column col2
now dim1 has both direction with fact1, is it available that dim2 has both direction with fact1?
I tried but it seems unable to create two both direction and want to know if I have some mistake, Thank you.
Anonymous , if you have two facts and two dimensions, You can not have all bi-directional relationships. As it creates loops or multiple paths. Keep one of the dims in a single direction.
Bi-Directional joins are also not recommended because of performance reasons.
Anonymous , I think with one fact you should be able to do. The thing is that there should not be two paths or loops.
Say A- Fact - C
A- Fact2 - C
When it is bi-direction you have two paths
A- Fact - C - Fact2
A- Fact2
3 Replies
- amitchandak
Super User
Anonymous , if you have two facts and two dimensions, You can not have all bi-directional relationships. As it creates loops or multiple paths. Keep one of the dims in a single direction.
Bi-Directional joins are also not recommended because of performance reasons.
- amitchandak
Anonymous , I think with one fact you should be able to do. The thing is that there should not be two paths or loops.
Say A- Fact - C
A- Fact2 - C
When it is bi-direction you have two paths
A- Fact - C - Fact2
A- Fact2