Hi PJ,
Having been a C programmer for a while this makes perfect sense to me.
You call mysql_(real)_query to execute the query and get the results
from the server. Because the MySQL library doesn't know when you've
finished with the result-set, you have to tell it to write the results
to memory (mysql_store_result.) This can then be read using
mysql_num_rows and other data retrieval functions.
This sentence in the manual makes this clear:
"After you have called mysql_store_result() and gotten back a result
that isn't a null pointer, you can call mysql_num_rows() to find out how
many rows are in the result set."
When you're finished with the result-set you can then use
mysql_free_result to release the memory allocated by the library.
What difficulties are you having with error checking? Most MySQL
functions return NULL if the operation fails - mysql_real_connect,
mysql_store_result etc. Others return non-zero, like mysql_real_query.
All the function documentation in the manual gives the return codes and
how to tell if a call failed.
Personally I've found the MySQL manual the best of any documentation for
systems we use, although I agree an example of a simple client/query
would have been useful.
Regards,
Andy
PJ wrote:
What is this supposed to mean from the manual:
The use of |mysql_num_rows()|
<http://dev.mysql.com/doc/refman/5.0/en/mysql-num-rows.html> depends on
whether you use |mysql_store_result()|
<http://dev.mysql.com/doc/refman/5.0/en/mysql-store-result.html> or
|mysql_use_result()|
<http://dev.mysql.com/doc/refman/5.0/en/mysql-use-result.html> to return
the result set....
|mysql_num_rows()|
<http://dev.mysql.com/doc/refman/5.0/en/mysql-num-rows.html> is intended
for use with statements that return a result set, such as |SELECT|
<http://dev.mysql.com/doc/refman/5.0/en/select.html>.
Does this mean you have to use
mysql_store_result() before using mysql_num_rows() ?.... kind of doesn't
make sense to have to do that. And there are no clear cut examples or
explanations...
I do not wish to piss-and-moan but I do find that there is a lot to be
desired in the manual; things that are very ;contradictory and/ or
unclear and certainly lacking in examples.
And please, somebody guide me to some tutorial or something where I can
learn to set up proper error checking so you guys don't have to listen
to my problems. :'(
--
MySQL General Mailing List
For list archives: http://lists.mysql.com/mysql
To unsubscribe: http://lists.mysql.com/mysql?unsub=arch...@jab.org
