Re: re-using variables

Tim Streater wrote:
In article <1172668483.913253.134510@xxxxxxxxxxxxxxxxxxxxxxxxxxx>,
"Mitesh" <oopsbabies@xxxxxxxxxxx> wrote:

Jerry Stuckle wrote:
Michael Fesser wrote:
.oO(Jerry Stuckle)

Toby A Inkster wrote:

You have:

$res = mysql_query("SELECT * FROM table1");
...
$res = mysql_query("SELECT * FROM table2");
if(!$res)
return;

$res is still going to be set as a result of your first query.

Use unset($res) between each query.
No, Toby.

$res will have the results of the second query. The resource returned
by the second query (or false) will overwrite what was in $res.
Try that with PDO and it will crash most likely. Overwriting $res will
not necessarily free the previous result set, which might then lead to
MySQL complaining about an unbuffered query or something like that.

| You cannot use the same variable for a PDOStatement object twice. As
| others have pointed out it works when you set this variable to null in
| between.

http://bugs.php.net/bug.php?id=35793

Micha
We're not talking PDO , Micha.

--
==================
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Jerry Stuckle
JDS Computer Training Corp.
jstucklex@xxxxxxxxxxxxx
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Ok if we need to call, mysql_free_result for mysql resources doesn't
that mean every other type of resources bound this way to a variable
must have a freeing function that has to be called before the variable
can be re-used? So doesn't it coincide with what I am saying that
variables bound to resources when re-used may cause problems. (and
according to the others post the variables can be re-used if the
previously allocated resource is freed)

My understanding was that, if you re-use $res without a call to mysql_free_result, it re-uses what $res is, which is a pointer to a result set, but doing that does *not* free up the space used by the result set. At least that's how it used to be. I don't know if they have improved the internals such that mysql_free_result is now a dummy call, or whether that is inherently impossible because mysql itself holds the result set.

Perhaps a guru can enlighten us.

-- tim

Tim,

I'm not a guru. But when you make certain calls to MySQL, it will hold certain resources for the result set. mysql_free_result() is anything BUT a dummy call.

Similar calls exist in most SQL databases for the same reason.

--
==================
Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.
jstucklex@xxxxxxxxxxxxx
==================
.

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