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First published by Douglas Correa (7Microsoft Partne)
When: 6 Jun 2013 5:21 PM
Last revision by Naomi N (eMicrosoft Partne)
When: 4 Sep 2013 9:26 AM
Revisions: 5
Comments: 4

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Thinking in Sets

Thinking in Sets is a great book by Joe Celko. This book tells us about concepts, how we need to think when we are working with databases.

Columns are not fields, rows are not records and tables are not files, hence SQL is declarative, not procedural. There is no sequential access or ordering in table, so “first,” “next,” and “last” rows are totally meaningless.

I agree when he writes “One of the first things that a newbie does is use a proprietary autonumbering feature in their SQL product as a PRIMARY KEY”. This is completely wrong, and it violates the definition of a relational key.

An attribute has to belong to an entity in the real world being modeled by the RDBMS. Autonumbering does not exist in an entity in the real world being modeled by the RDBMS. Thus, it is not an attribute and cannot be in a table, by definition.

That’s how I think and was totally wrong before.

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Thinking in Sets

Thinking in Sets

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