Re: How to determine if a function exists

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От lmanorders
Тема Re: How to determine if a function exists
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Msg-id 071950FA770E4854B5E609D07EACB389@LynnPC
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Ответ на Re: How to determine if a function exists  (Tom Lane <tgl@sss.pgh.pa.us>)
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> "lmanorders" <lmanorders@gmail.com> writes:
>> I'm attempting to determine if a stored procedure exists. If it doesn't,
>> then I want to create it. I'm developing in C++ using the libpq
>> interface. I found the following suggestion in the docs to determine if a
>> function exists or not. I tried creating what I think is an identical
>> query in pgAdmin and it seems to work ok. Can anyone tell me why the
>> following always returns PGRES_TUPLE_OK, whether the function exists or
>> not?
>
> PGRES_TUPLES_OK means you successfully executed a SELECT (or other
> command capable of returning tuples).  It doesn't imply anything about
> how many tuples were returned.  In this case, you'd want to check for
> PQntuples() > 0, as well.  And perhaps think about what you'd do if
> you got more than one match, which is quite possible in view of function
> overloading, schema search path, etc.
>
> regards, tom lane
>

Thanks. That works great!



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