Chapter 4 Working with Conceptual Data Models
The following CDM model checks are made on relationships:
| Check | Description and Correction |
|---|---|
| Relationship name and code uniqueness | Relationship names and codes must be unique in the model.
Manual correction: Modify the duplicate name/code Automatic correction: Appends a number to the duplicate name/code. |
| Reflexive dependency | A dependency means that one entity is defined through a relationship with another. A dependent relationship cannot therefore be reflexive.
Manual correction: Change or delete the reflexive dependency. Automatic correction: None. |
| Reflexive mandatory relationship | A reflexive mandatory relationship exists.
Manual correction: Deselect the Mandatory check boxes for the relationship to be non-mandatory. Automatic correction: None. |
| Bijective relationship between two entities | There is a bijective relationship between two entities when there is a two-way one to one relationship between the entities. This is equivalent to a merge of two entities.
Manual correction: Merge the entities or modify the relationship. Automatic correction: None. |
| Name uniqueness constraint for many to many relationships and entities | A many-to-many relationship and an entity cannot have the same name or code.
Manual correction: Change the name or code of the many-to-many relationship or the name or code of the entity. If you do not, PDM generation will rename the generated table. Automatic correction: None. |
| Consistency between dominant and dependent relationships | A dependent relationship between entities cannot also be a dominant relationship.
Manual correction: Select the Dominant check box on the other (correct) side of the relationship. Automatic correction: None. |
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