How to change operator of join conditions in where clause?

Question

Hello
I have a situation... I want to change the operator between each join conditions in the where clause when these join conditions are not from the same join..
For example, I have the following schema:
Dim1 ------ DimA -------Fact1
Dim1-------DimB -----Fact1
So DimA and DimB are aliasas of one dim table, but the join is different.
Now if I run this model, what I will get in the where clause of the query is:
Where Dim1 = DimA and Dim1 = DimB and DimA= Fact1 and DimB = fact1.
Is there a way I can change these "and" operator to "OR", so that the where clause would look like this: Where Dim1 = DimA and Dim1 = DimB and DimA= Fact1 OR DimB = fact1?
This is different from simply changing the join operator within the same join, because these are different joins and I'd like to control how they relate to each other..
Please help
Thanks

Answer 1

Sometimes, business rules are complex, so there isn't always a way to simplify things.  Is your issue that it's complex and error prone, or is it performance due to the OR clauses?
One possibility that will at least make it easier to test and debug is something like this:  (pseudocode)
From Table1 Inner join Table2 on x=y etc.etc.
CROSS APPLY
(Select case when a=b and (c=d or e=f) then 1 else 0 end) as Situation1
, case when h=i or j = k then 1 else 0 end) as situation2
, case when l = m then 1 else 0 end) as situation 3
) as CA_Logic_Simplifier
Where situation1 = 1 and situation2 = 1 and situation3 = 1
Although you could say, "Hey, this is basically doing the same thing as before", this approach would be far easier to test and debug, because you can at a glance look at the values for situation1, 2, 3, etc. to see where errors are being introduced. 
The cross apply makes the columns situation1/2/3 "instantiated", so they are usable in the where clause. Divide and conquer.