Re: Pro*C/C++ Cursors - How to count the number of results.

In article <176ffe5.0107240105.6f6a0f48_at_posting.google.com>, gregory_at_harmonycom.com says...
>
>Hi !
>I am using Pro*C/C++ and i've the following questions :
>
>* after i'm opening a cursor, how can i know how many
> rows were found without performing additional queries
> (like select count (...)) ?
>

we only know the answer to that AFTER you fetch the last row. We don't "preanswer" queries. Consider what the effects of:

select * from one_billion_row_table

would be otherwise. You have to fetch the data in order to know the cardinality of the result set.

>* what is more efficient, to use a cursor or a host array as
> output variable in the INTO clause of SELECT ?
>

select INTO's return

o at least one row
o at most one row

If you are asking for at least and at most one row, the select INTO is the proper way to go.

If you are getting 0, 1 or more rows -- a cursor with host arrays is the way to go.

You should not replace a select into with an explict cursor/fetch into an array since there is at least/most one row (no array needed).

>Thanks for answers !
>Gregory
>gregory_at_harmonycom.com

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