How to Build a Business Rules Engine

be extended to capture relationship information as well. This is necessary for those

columns that are foreign keys, that is, have a corresponding column in a parent table.

The rules engine must be able to quickly navigate to the parent table and extract

information from it. Since this only applies to foreign keys it only affects metadata

for the child entity in a relationship. There is no need to extend Column to deal with

relationship information that concerns the parent entity of a relationship.

This requirement has already been met in the design described in the previous

chapter, where the following attributes were added to the Column table.

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