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Home -> Community -> Usenet -> c.d.o.server -> Re: user-defined functions
On Wed, 30 Dec 1998 14:38:17 GMT, andrewf_at_jaredgroup.com wrote:
>In article <3689C79F.9AB8EC77_at_sybrandb.demon.nl>,
> Sybrand Bakker <postbus_at_sybrandb.demon.nl> wrote:
>>
>> In the past I have been working with user-defined functions in selects which
>> were issuing additional selects (I didn't design them luckily). The
>> performance of this was usually quite bad.
>
>User defined functions should be designed carefully. There are situations you
>just need these additional selects and the function can simplify your code and
>give better performance.
>
>My concern is, it is said that user defined functions are not subject to
>Oracle read consistent model. If so, be more careful as you may get
>inconsistent result.
Can you give more details about this possible read inconsistency or give any reference to the literature where this is mentioned? I'm not avare and have not read of any such warnings about using user defined PL/SQL functions.
As I understand it, that's why function's purity level must be specified with "PRAGMA RESTRICT REFERENCES" if you wan't to use function in SQL command. If this specified purity level is violated during execution, oracle will not execute the function and ORA error will be returned.
Regards,
Jurij Modic <jmodic_at_src.si>
Certified Oracle7 DBA (OCP)
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