User-defined function: Difference between revisions

Revision as of 19:21, 19 August 2006

Revision as of 11:18, 24 August 2006

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* parameter style - defines the conventions that are used to pass the function parameters and results between the implementation of the function and the database system (only applicable if language is not SQL).

* specific name - a name for the function that is unique within the database. Note that the function name does not have to be unique, considering overloaded functions.

* determinism - specifies whether the function is deterministic or not. The determinism characteristic has an influence on the [[query optimizer|query optimizer]] when compiling a SQL statement. The rewrite of SQL statements may not change the number of function invocations for non-deterministic functions.

* SQL-data access - tells the database management system whether the function contains no SQL statements (NO SQL), contains SQL statements but does not access any tables or views (CONTAINS SQL), reads data from tables or views (READS SQL DATA), or actually modifies data in the database (MODIFIES SQL DATA).

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* [http://msdn.microsoft.com/library/en-us/tsqlref/ts_create_7r1l.asp Microsoft SQL Server reference for CREATE FUNCTION]

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

[[Category:Computer programming]]