2. FAN TRAP
It 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.
3. Fan trap occur in a situation when a model
represents relationship between entity types
however a path between certain entity
occurrences is ambiguous.
Example: (Staff)-1:N-has-1:1-(Division)-1:1-
operates-1:N-(Branch) in this model it may be
impossible to determine the branch a staff
belongs to, in the situation when staff belong to
division having more than 1 branches.