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All Tags » SQL » Data Modelling
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According to InfoWorld, Bill Gates thinks that declarative modelling of business logic has not caught on because of "weak models".
This is a surprise. E.F.Codd's earliest papers on the Relational Model described a relational calculus for the purpose of supporting declarative business logic. Even the SQL standards committee added ...
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My post on Disjoint Subtypes generated some interesting feedback.
I made a point of saying that the Products table in my schema is in BCNF. That’s because the only determinants are supersets of {SKU}, which is the only key. The point I wanted to make was not about normalization as such but about the nature of SQL UNIQUE and PRIMARY KEY ...
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Entity subtyping is a very common data modelling scenario that gets extensive coverage in books on relational design but it isn’t necessarily well supported by SQL DBMSs. The following is a simple technique I have found useful for implementing some kinds of entity subtypes. Specifically it applies to the case of Disjoint Subtypes that ...
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