if a table which is going to connect some other table with
one- to- many cardinalities which is having cardinalities
with some other tables

when there is one-to-many jointo a table that "fans out"
into another "one- to-many" join to another table.this
problem is called fan trap.

A fan trap is a type of join path between three tables when 
a “one-to-many”
join links a table which is in turn linked by another “one-
to-many” join. The
fanning out effect of “one-to-many” joins can cause 
incorrect results to be
returned when a query includes objects based on both tables.