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  • Open Daily: 10am - 10pm
    Alley-side Pickup: 10am - 7pm

    3038 Hennepin Ave Minneapolis, MN
    612-822-4611

Open Daily: 10am - 10pm | Alley-side Pickup: 10am - 7pm
3038 Hennepin Ave Minneapolis, MN
612-822-4611
Database Technology: Nulls Considered Harmful

Database Technology: Nulls Considered Harmful

Date, Chris

Paperback

DatabasesGeneral Computers

Publisher Price: $49.95

ISBN10: 1634624769
ISBN13: 9781634624763
Publisher: Technics Publications
Published: Jul 8 2024
Pages: 246
Weight: 0.95
Height: 0.52 Width: 7.50 Depth: 9.25
Language: English

Essentially all truly general purpose database systems today are based on the relational model of data. That model was invented by E. F. (Ted) Codd in the late 1960s and early 1970s, during his employment at the IBM Research Laboratory in San Jose, California, and it was solidly based on conventional two-valued logic, 2VL. Unfortunately, those same general purpose database systems today all use the language SQL as their user language-and SQL is based not on 2VL but on what's called three-valued logic, 3VL, instead, and uses what are called nulls to represent missing information. In fact, Codd himself subsequently extended his original model to support 3VL and nulls as well. (Actually, basing SQL on 3VL and adding 3VL to the relational model seem to have occurred in lockstep, as it were. Certainly both developments occurred at the same place-the IBM San Jose Research Laboratory-at more or less the same time.)

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