Well, when we talk about Universe, (hello we are not talking about universe in solar system) in Universe Designer we mostly talk about loops, traps which in turn make us think about Contexts and Aliases.
We will discuss only contexts. I will probably come with another post on traps and aliases.
We use contexts when there is a loop among tables. For example consider there are 4 tables A, B, C and D.
Consider that there are joins from A to B, B to C and A to D & D to B. It clearly forms a loop.
So now the users want to pull objects from A & C tables. As there is no direct join between A and C which table it should use either B or D in order to form a query.
Contexts come in such scenario.
In simple terms, a Context defines a path. In the above example we can create two contexts.
Context 1 : A to B to C
Context 2 : A to D to C
Best practice to define contexts when we have multiple star schemas and snow flake schemas is to define one context for each schema.
In the above example we can consider B and D are two fact tables and A and C are two dmension tables. Total we have two star schemas. So we have defined two contexts.
The same we can follow for Snow flake schemas.
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