Re: libpq: multiple commands within single query

Yeah - that is how I do (PGgetResult function returns results until it will
return "NULL" pointer which means that all data for whole "PGsendQuery" was
returned). But what does it mean when query which contain 3 "SELECT"
commands returns just one result (second "PGgetResult()" already returns
null pointer)?

18 января 2011 г. 14:55 пользователь Dmitriy Igrishin
<dmitigr(at)gmail(dot)com>написал:

> Hey,
>
> 18 января 2011 г. 14:24 пользователь Вячеслав Блинников <slavmfm(at)gmail(dot)com
> > написал:
>
> By which rules database returns results for multiple commands within single
>> query?
>> For example I send (execute) such query (obtain different information
>> about just connected client):
>> "SELECT column1 FROM table1; SELECT column2 FROM table2; SELECT column3
>> FROM table3;"
>> And when I get response I expect some results (PGresult structure) for
>> EACH "SELECT" - so there must be 3 PGresult structures and if one of results
>> contains zero rows - it means that there are no data (of such type) for such
>> client yet, but there still can be some data for following "SELECT". For
>> example (referring to previous example) response can contain 3 results (as I
>> expect) where first contains 1 row, second 0 rows and third 1 row. So when I
>> examine the response I can match each PGresult to each "SELECT".
>> Does it works on this way? Or I missed something?
>>
> According the documentation: "the client can be handling the
> results of one command while the server is still working on later
> queries in the same command string.". The key word here is "later".
>
> --
> // Dmitriy.
>
>
>