File:Referential integrity broken.png
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Referential_integrity_broken.png (548 × 442 pixels, file size: 11 KB, MIME type: image/png)
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Summary[edit]
DescriptionReferential integrity broken.png |
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) |
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Licensing[edit]
This file is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license. Subject to disclaimers. | ||
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This licensing tag was added to this file as part of the GFDL licensing update.http://creativecommons.org/licenses/by-sa/3.0/CC BY-SA 3.0Creative Commons Attribution-Share Alike 3.0truetrue |
Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled GNU Free Documentation License. Subject to disclaimers.http://www.gnu.org/copyleft/fdl.htmlGFDLGNU Free Documentation Licensetruetrue |
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Date/Time | Thumbnail | Dimensions | User | Comment | |
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current | 08:35, 6 April 2007 | 548 × 442 (11 KB) | AutumnSnow (talk | contribs) | {{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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