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Posted by Tim Streater on 02/27/07 20:44
In article <1172596225.876668.42750@k78g2000cwa.googlegroups.com>,
"Mitesh" <oopsbabies@hotmail.com> wrote:
> Hi all,
>
> I have the following code:
>
> $req = "SELECT * FROM table1";
> $res = mysql_query($req);
>
> if(!$res)
> return;
>
> while($line = mysql_fetch_array($res))
> {
> .............
> .............
> }
>
> $req = "SELECT * FROM table2";
> $res = mysql_query($req);
>
> if(!$res)
> return;
>
> while($line = mysql_fetch_array($res))
> {
> .............
> .............
> }
>
> What I have discovered is re-using the $req variable is fine. While re-
> using the $res produces undefined result (sometimes the second query
> works fine and sometimes it doesn't. When I use different variables
> like $res1 and $res2 the mysql queries always succeed. Is the initial
> approach of re-using variable wrong if variables contain a
> resource(reference type)?
>
> In other words since PHP uses garbage collection re-using the same
> variable can cause problems. Is this true?
Pass. But I systematically do mysql_free_result($res) whether I need to
or not, not just before a re-use of $res in another query, but also at
the end of the script. I don't know how it works internally or how much
one needs to worry about this.
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