many to many relationships

[churchy]

Hi everyone,

I have doubts about many to many relationships...
is compulsory to simplify them?
what happens if i don't simplify.... report data will be wrong or maybe is a performance issue?
Where do i have to simplify the model, in the database view or in business view?

Thanks!

[ggreddi]

Hi
many to many releationships can handled by cognos..

Simolify the model in Databaseview itself.

Cheers
GG

[churchy]

thanks for ur answer ggreddi ,

the question is... is compulsory or recommended to simplify it at all? what happens if i dont simplify? any suggestion about how to simplify this kind of relationships? i dont find any example on the documentation...

[praveennb]

The way i would do it, Many to Many Relation should be handled  inside the Database by creating a new table that contains
key value from both the tables, then import this table to Framework manager.

[churchy]

Hi BI007,

But what about if i cant create that table in the database... in my case i cant do it, database is already into production and locked for me...

Can i leave the relation as is in the database view or it raise wrong data in my reports?

thanks

[Suraj]

many to many can be handled in FM if you don't have access to the database.
Just ignore the relationship from database and create your own in the model.
the reports get relationship information from the model.

[churchy]

thanks for your answer Suraj, i got it, my doubt is where to simplify it, directly on data base view, or leave n:n relationshiip on dbview and normaliza it on business view...

[MFGF]

Hi,

This is really a logical problem rather than a technical one.  If you have a many-to-many relationship, often it will not be suitable for use in reporting because it does not allow authors to determine exact results.  For example, if you have a many-to-many relationship between suppliers and parts, you cannot then report on a) who specifically supplied a part, or b) which parts were supplied by a particular supplier.  What's missing is the data that ties each part to it's supplier and vice versa.  Usually your business will be recording this somewhere, so it's your job to find where it's being held and bring it into your model - you can then use this to resolve your many-to-many relationship into something more usable.

Just a thought...

MF.