Relationship Checks (CDM/LDM)

The following CDM/LDM 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

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.

Relationship with child shortcut

External shortcut could be generated as child table. An entity that is at the "many" end of a one-to-many relationship or which is non-dominant should not be an external shortcut as the reference will not be generated during the generation of a PDM.

Manual correction: Change the cardinality of the relationship cardinality or the entity, which should not be an external shortcut.

Automatic correction: None.

'Many-many' relationships

[LDM only] 'Many-to-many' relationships are not permitted.

Manual correction: Create an intermediary entity, which contains the primary identifiers of the previous 'many-to-many' entities.

Automatic correction: None.


Created October 7, 2009. Send feedback on this help topic to Sybase Technical Publications: pubs@sybase.com