I have read the article from Dave on fan traps,A->B->C. Does it mean that if B and C have measures in them then it is a fan trap. Or does it have to be a specific on the type of the measures like for example may be total for orders in B and number of orders in C.
hartford27 
(BOB member since 2006-11-22)
This is correct.
Marek Chladny 
(BOB member since 2003-11-27)
Can you give me an other example where B and C have measures and they have fan trap. My understanding is that if the measures are using aome aggregate functions they have fan trap…
hartford27 (BOB member since 2006-11-22)
The fan trap occurs not because of the aggregating functions used for measures coming from B and C tables but because of the 1:N joins between A and B and B and C:
A — (1:N) — B — (1:N) — C
Another example can be for instance:
A is any dimension (for instance DATES)
B is a table with shipping information and data is on a package level
C is a detailed table with an info on a package items level
If you had a measure (for instance “number of packages”) from B and a measure from C (for instance “number of package items”) from C then you would have a fan trap.
Marek Chladny (BOB member since 2003-11-27)
Hi Marek,
i have one query on your ans.
as per your reply if we chosse measure from B and C table then its fan trap.
for e.g i have three tables.
Customer (one customer in many branch)
Branch (one branch have many accounts)
Account
so relationship between tables are 1:N and 1:N.
if i fetch objects from branch and account table not measure its again fan trap or not?
like branch code and account number?
amitrathi1234 
(BOB member since 2007-10-15)
Do you know why a fan trap is a problem?
Dave Rathbun (BOB member since 2002-06-06)