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Lesson Navigation IconRelationales Datenmodell

Unit Navigation IconKonzepte

Unit Navigation IconAbbildung ER-Schema

LO Navigation IconERM concepts

LO Navigation IconRule 1

LO Navigation IconRule 2

LO Navigation IconRule 3

LO Navigation IconRule 4

LO Navigation IconRule 5

LO Navigation IconRule 6

LO Navigation IconRule 7

LO Navigation IconRule 8

LO Navigation IconAnwendung der Regeln

LO Navigation IconUmwandlungsübung

Unit Navigation IconData integrity

Unit Navigation IconNormalisierung

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Rule 7

If in rule 1 multivalued attributes are encountered, they are transformed into separate relational schemes according to this rule.

Definition rule 7

Define for each multivalued attribute A a new relational scheme R' which also contains this attribute A and the primary key of the according relational scheme R. Together they form the primary key for R'.

In this example you can see the application of rule 7:

RuleRegel 7

A new relational scheme is created for the multivalued attribute TelNo containing TelNo as attribute:

ChiefTelNo(TelNo)

The primary key of this multivalued attribute connected to the relational scheme is used as foreign key in the new scheme:

ChiefTelNo(ChiefEditor_PersNo, TelNo)

The foreign key and the attribute together form the primary key for this new relational scheme:

ChiefTelNo( ChiefEditor_PersNo, TelNo)

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