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| Re: ON DELETE CASCADE and ON UPDATE CASCADE [message #385482 is a reply to message #385475] |
Mon, 09 February 2009 19:56   |
rleishman
Messages: 3728
Registered: October 2005
Location: Melbourne, Australia
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Senior Member |
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ON DELETE CASCADE means when you delete the parent of a foreign key relationship, the chilren are deleted too. It is supported natively by Oracle - you can specify it when you create a foreign key constraints
ON UPDATE CASCADE means that when you update the PRIMARY KEY on the parent of a foreign key relationship, the FOREIGN KEY of the child is also updated. It is NOT supported natively by Oracle - you must code it yourself using triggers.
Ross Leishman
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| Re: ON DELETE CASCADE and ON UPDATE CASCADE [message #385671 is a reply to message #385482] |
Tue, 10 February 2009 08:36 |
dandeliondream
Messages: 12
Registered: February 2009
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Junior Member |
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| rleishman wrote on Mon, 09 February 2009 19:56 | ON DELETE CASCADE means when you delete the parent of a foreign key relationship, the chilren are deleted too. It is supported natively by Oracle - you can specify it when you create a foreign key constraints
ON UPDATE CASCADE means that when you update the PRIMARY KEY on the parent of a foreign key relationship, the FOREIGN KEY of the child is also updated. It is NOT supported natively by Oracle - you must code it yourself using triggers.
Ross Leishman
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Thanks for the explanation. I think i have a better understanding now.
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