“CODASYL Data-Base Management Systems”
- Records have types.
- There is a set type (one record of the owner record type -> N records of the member record type).
- A record can not occur as a member of two sets of the same set type.
- Can’t model many to many relationships directly because it would lead to a violation of the above rule; we define an auxiliary record type that represents that relationship.
- N-dimensional associations through intersection records.
- Recursive structures are represented through a relationship record type and two relationships: has-substructure and has-superstructure.
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