Cardinalities in Framework manager

[Aregone]

Hi all,
     I am new to report authoring...I have developed a report and sent to the testing team...But its back with performance issues...I want to check the cardinalities in FM....In business objects we have context where in it will show all the rlationships and cardinality...How do I do it in cognos8...Kindly help...Hw to implement left outer join cardinality b/w 2 query subjects in FM...I am new to cognos...kindly advice even if Qs seem to be simple and silly.........Thanks to all in advance

[krishna23]

Hi,

IBM Cognos 8 supports both minimum-maximum cardinality and optional cardinality.

In 0:1, 0 is the minimum cardinality, 1 is the maximum cardinality.

In 1:n , 1 is the minimum cardinality, n is the maximum cardinality.

A relationship with cardinality specified as 1:1 to 1:n is commonly referred to as 1 to n when focusing on the maximum cardinalities.

A minimum cardinality of 0 indicates that the relationship is optional. You specify a minimum cardinality of 0 if you want the query to retain the information on the other side of the relationship in the absence of a match. For example, a relationship between customer and actual sales may be specified as 1:1 to 0:n. This indicates that reports will show the requested customer information even though there may not be any sales data present.

Therefore a 1 to n relationship can also be specified as:

0:1 to 0:n

0:1 to 1:n

1:1 to 0:n

1:1 to 1:n

Use the Relationship impact statement in the Relationship Definition dialog box to help you understand cardinality. For example, Sales Staff (1:1) is joined to Orders (0:n).


It is important to ensure that the cardinality is correctly captured in the model because it determines the detection of fact query subjects and it is used to avoid double-counting factual data.

When generating queries, IBM Cognos 8 follows these basic rules to apply cardinality:

Cardinality is applied in the context of a query.

1 to ncardinality implies fact data on the n side and implies dimension data on the 1 side.

A query subject may behave as a fact query subject or as a dimensional query subject, depending on the relationships that are required to answer a particular query.

Thanks,
kris

[blom0344]

Hi all,
     I am new to report authoring...I have developed a report and sent to the testing team...But its back with performance issues...I want to check the cardinalities in FM....In business objects we have context where in it will show all the rlationships and cardinality...How do I do it in cognos8...Kindly help...Hw to implement left outer join cardinality b/w 2 query subjects in FM...I am new to cognos...kindly advice even if Qs seem to be simple and silly.........Thanks to all in advance

Cognos8 does NOT have an exact equivalent to the context mechanism in BusObj. Whereas you can enforce multiple facts on BusObj through the appliance of contexts, you can only reach the same through cardinality settings in Cognos8

Make sure that you only define 0:1 and 0:n if you need it. Generating outer joins can severaly hinder performance. A rule of thumb is that you may need outer joins when the fact has nullable foreign keys..