File:Referential integrity broken.png

Referential_integrity_broken.png ‎(548 × 442 pixels, file size: 11 KB, MIME type: image/png)

Summary

Description

An example of a database that has not enforced referential integrity. In this example, there is a foreign key (artist_id) value in the album table that references a non-existent artist — in other words there is a foreign key value with no corresponding primary key value in the referenced table.

This anomaly came about when the record for an artist called "Aerosmith", with an artist_id of "4", was deleted from the artist table, even though the album "Eat the rich" referred to this artist. If referential integrity had been enforced, the deletion of the main record would have been possible, but its associated record would have been deleted as well. Alternatively, the existence of an associated record would not allow the delete operation of the referenced record, and instead return an error code.
Date
Source en:Image:Referential integrity broken.PNG
Author en:User:Ta bu shi da yu
Permission
(Reusing this file)		 GFDL
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inception

19 July 2005

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Date/TimeThumbnailDimensionsUserComment
current08:35, 6 April 2007Thumbnail for version as of 08:35, 6 April 2007548 × 442 (11 KB)AutumnSnow{{Information| |Description= An example of a database that has not enforced referential integrity. In this example, there is a foreign key ('''artist_id''') value in the album table that references a non-existent artist &mdas
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