User-defined function: Difference between revisions

Revision as of 04:35, 17 May 2006

Revision as of 00:37, 8 June 2006

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A '''User Defined Function''', or '''UDF''', is an [[extension (computing)|extension]] to an [[SQL]] [[database server]] (like [[MySQL]]) that can be compiled for use in an SQL [[database query language|query]]. For example, sometimes it may be necessary to obtain a [[random]] number for use as a [[primary key]] (a function that MySQL does not internally support). In this case, a new, external function could be written and compiled to accomplish this task.

One sample of such a query could be: <code>SELECT GETRANDOMKEY();</code>.

Essentially, this external function becomes part of the server itself.

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* [http://dev.mysql.com/doc/refman/5.0/en/adding-functions.html MySQL manual section on UDFs]

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[[Category:Computer programming]]

[[Category:Databases]]