Confirming Analysis › Checking for Correctness › Quantity Cross-Checking

Quantity Cross-Checking

You use quantity cross-checking to check the consistency of all quantitative information gathered about objects in the analysis model.

In particular, you check two items:

• Relationship cardinality

  When two entity types are associated, the entity volume figures must be consistent with the cardinality of the relationship associating them.

  For example, if customer has 15 occurrences, and order has 150 occurrences, the cardinality of the relationship between customer and order should average 10 (150 divided by 15).

  The cardinality of a relationship depends on the optionality of the entity types it associates. The following illustration shows the cardinality of a relationship between entities A and B under three conditions.

• Subtype volume

  The number of entities of a given type cannot exceed the combined total of maximums for all subtypes in a partitioning. Each mandatory partitioning must have the same combined total.