At the university course DBMS. We were asked to compile an ER-model of a developmental database for children. Almost did everything, it remains only to deal with the connection between the essence of the Parent and the essence of the child. It is clear that the connection is many to many. It is necessary to get rid of it somehow. But how to do it, what can I add?
- I would not do as many to many as the child has two parents, but only one dad, just like my mother. - Dmitry Polyanin
- But then what happens, the two entities father and mother? But then they will have common attributes. And what attributes will differ? The task contains the attributes: name, phone number and address of residence. - J. Doe
- The essence is one, just a child has two fields "father" and "mother" and both refer to the same table of parents. - Mike
- @Mike, I could be wrong, but the Entity-Relation model seems to be called that, because there the connections between the entities are established. How can I establish a connection between an entity and individual attributes? It seems to me that it is necessary to add an additional entity with additional information so that a one-to-many connection is from the parent and the same connection is from the child. - J. Doe
- And what will be in this separate table? there will be for example two attributes a child and a parent. And the connection with other tables will still be specific attributes. there is always a link attribute - Mike
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