Understanding Your Data Model › Using Relations › Examples of Using Known by Relation

Examples of Using Known by Relation

Example 1: A Single Known by Relation - Company

Suppose you wish to identify companies by a company code.

A Company could be defined as follows:

FIL  Company         REF     Known by        FLD     Company code    CDE

FIL  Company         REF     Has     FLD     Company name    TXT

This results in the following entries:

Example 2: Multiple Known by Relations - Manager

There may be more than one Known by relation on a file. For example:

FIL   Event   REF     Known by        FLD     Date            DT#

FIL  Event   REF     Known by        FLD     Time            TM#

FIL  Event   REF     Has     FLD     Location                TXT

Note that the presence of more than one Known by relation on a file may indicate that an entity has been omitted from the model. For instance, consider the following relations to define a Manager:

FIL      Manager         REF     Known by        FLD     Manager type            STS

FIL  Manager         REF     Known by        FLD     Manager code            CDE

FIL  Manager         REF     Has     FLD     Manager name            TXT

FIL  Manager         REF     Has     FLD     Salary                  VAL

Neither Manager name nor Manager salary are properties of Manager type, which suggests that Manager type should be an entity in its own right, and that Manager should be Owned by Manager type.