This is a very complex question to answer. Mike is right.
In general, though, objects are usually associated through some sort of link or reference table. The ida2a2 values of the objects themselves (in their own db tables (WTPart, EPMDocument, etc)) will be in the RoleA (ida2a5, ida2a7, etc.) or RoleB (ida2b5, ida2b7, etc.) columns. There are usualy classname column associated with the RoleA and Role B columns to indicate what type of object the ida columns refer to (e.g. classnamekeyrolebobjectref, classnamekeyroleaobjectref, classnamekeya2a5, classnamekeya2b5, etc.)
Master tables (WTPartMaster, EPMDocumentMaster, WTDocumentMaster) are linked to the tables containing the info on the object iterations (WTPart, EPMDocument, WTDocument) are linked through the ida3masterreference column in the tables containing the iterated info.