Monday, August 27, 2012

What is Fan trap and Chasm Trap? How do you resolve?

Fan Trap: occurs when a “One to Many” join links a table which is in turn linked by another “One to Many” join.
There are two ways to solve Fan trap:
• Creating an alias and applying aggregate awareness function. This is the most effective way to solve the Fan trap problem.
• Using Multiple SQL statements for each measure.

Chasm Trap: occurs when two “Many to one” joins from two Fact tables converge on a single Lookup table.
Can be solved by:
• Creating a Context.
• Using Multiple SQL statements for each measure
• Creating multiple universes (WEBINTELLIGENCE only).

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