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Cardinality in Cognos Framework Manager

Cardinality

You must ensure that all relationships and cardinality correctly reflect your users’ reporting requirements.

Detecting Cardinality from the Data Source

Notation

When you interpret cardinality, you must consider the notation that appears at both ends of the relationship.
Possible end labels are
  • 0..1 (zero or one match)
  • 1..1 (exactly one match)
  • 0..n (zero or more matches)
  • 1..n (one or more matches)
The first part of the notation specifies the type of join for this relationship:
  • an inner join (1)
    An inner join shows all matching rows from both objects.
  • an outer join (0)
    An outer join shows everything from both objects, including the items that do not match. An outer join can be qualified as full, left, or right. Left and right outer joins take everything from the left or right side of the relationship respectively and only what matches from the other side.
Your users see a different report depending on whether you use an inner or outer join. For example, your users want a report that lists salespeople and orders. If you use an outer join to connect salespeople and orders, the report shows all salespeople, regardless of whether they have any orders. If you use an inner join, the report shows only the salespeople who have placed orders.
Data in one object might have no match in the other object. However, if the relationship has a minimum cardinality of 1, an inner join is always used and these records are ignored. Conversely, if all the items match but the relationship in the model has a minimum cardinality of 0, an outer join is always used, although the results are the same with an inner join. For example, the underlying table for one object contains a mandatory (non-NULLable) foreign key for the other. Ensure that the data and cardinalities match.
The second part of the notation defines the relationship of query items between the objects.

Cardinality in Generated Queries

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