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Re: [PROGRAMMERING] C++, mysql & hukommelse



Jan KC wrote:

Ehh. hvad er normalisering ?

Normalisering af en database er en design-proces hvor du nedbryder databasen i mindre tabeller. På den måde undgår du redundans og databasen vil typisk blive hurtigere.


En lille eksempel kunne være et adresse-kartotek. Du ønsker at gemme felterne navn, gade, postnr og by. Men eftersom postnr og by altid hænger sammen, kunne du have en tabel med ALLE landets postnr. og byer. Som primær nøgle kunne du bruge postnr.

I en anden tabel gemmer du nu navn, gade og postnr. Skal du bruge det hele, kan du udfra postnr hente byen i den anden tabel.

Enhver bog om SQL et eller flere afsnit om normalisering og design. Desværre er det lidt sendt at fortælle, at den 18. marts afholdt SSLUG et hyggemøde om emnet.

Kneth

--
Kenneth Geisshirt, M.Sc., Ph.D.         http://kenneth.geisshirt.dk
Grøndals Parkvej 2A, 3. sal                    sslug@sslug
DK-2720 Vanløse                                     +45 38 87 78 38



 
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