Hi,
Since MaxDB PHP uses unbuffered result sets, all subsequent calls to
maxdb_query() will return the out of sync error. This is due to
compatibility with MySQL's mysqli extension which forbids more than one
unbuffered result set.
The problem in your program is that maxdb_free_result() will be called
after the recursion finishes. In the meantime there are several calls to
maxdb_query() without a maxdb_free_result() between them.
It is a TODO to allow several open result sets with maxdb_query(). We
will inform you when this feature is available.
As a workaround you can use prepared statements like in the following
simplified example:
$leaf = /* ... */;
$stmt = maxdb_prepare($db_connection, "SELECT id, data FROM datatree
WHERE parent=?");
function process_data ($db_connection, $stmt, $leaf) {
maxdb_stmt_bind_param($stmt, "s", $leaf);
maxdb_stmt_execute ($stmt);
maxdb_stmt_bind_result($stmt, $id, $data);
while (maxdb_stmt_fetch($stmt)) {
use_data (/*...*/);
/* ... */
}
}
process_data($db_connection, $stmt, $leaf);
maxdb_stmt_close($stmt);
Regards,
Thomas
-----Original Message-----
From: Claus Windeler [mailto:[EMAIL PROTECTED]
Sent: Mittwoch, 9. Februar 2005 14:01
To: Simenec, Thomas
Cc: [email protected]
Subject: RE: PHP problem mith maxdb_query() and maxdb_real_query()
Hello!
Sorry, I forgot to write it when I simplified the code. In the real code
I wrote
If ($result = maxdb_query($db_connection, $sql)) {
/*....*/
}
resulting in the mentioned error. Seems I can't use maxdb_query in a
recursive
function ?? ... it worked when I used ODBC driver.
Bye
Claus
> Hi,
>
> For working on a result set with maxdb_fetch_assoc() you have to
> retrieve the result set with maxdb_query() first.
> The right way to write the if condition is
>
> If ($result = maxdb_query($db_connection, $sql)) {
> /* ... */
> }
>
> Regards,
>
> Thomas Simenec
> SAP Labs Berlin
>
> -----Original Message-----
> From: Claus Windeler [mailto:[EMAIL PROTECTED]
> Sent: Mittwoch, 9. Februar 2005 13:01
> To: [email protected]
> Subject: PHP problem mith maxdb_query() and maxdb_real_query()
>
>
>
> I have a recursive function to process data which is organized in a
> tree. The
> data is stored in a database.
>
> I am using PHP 5 with MaxDB-Module 1.0
>
> First I tried the following version of my function
>
> function process_data($leaf) {
>
> $sql = 'SELECT id, data FROM datatree WHERE parent='.$leaf;
>
> if (maxdb_query($db_connection, $sql)) {
>
> while ($row = maxdb_fetch_assoc($result)) {
>
> use_data($row['DATA']);
>
> // check if childs should be processed. Not always true.
> if (process_childs($row['ID'])) process_data($row['ID']);
>
> }
>
> maxdb_free_result($result);
>
> }
>
> }
>
> This results in an maxdb_query error when function is called the
second
> time
> during recursion:
>
> function.maxdb-query: Commands out of sync. You can't use this command
> now.
>
>
> I modified the function to use maxdb_real_query():
>
> function process_data($leaf) {
>
> $sql = 'SELECT id, data FROM datatree WHERE parent='.$leaf;
>
> if (maxdb_real_query($db_connection, $sql)) {
>
> $result = maxdb_store_result($db_connection);
>
> while ($row = maxdb_fetch_assoc($result)) {
>
> use_data($row['DATA']);
>
> if (process_childs($row['ID'])) process_data($row['ID']);
>
> }
>
> maxdb_free_result($result);
>
> }
>
> }
>
> When I execute it my Apache-Webserver hangs an I have to restart it.
>
> Can someone show me the right way to implement the function or point
me
> to my
> mistake ??
>
> Bye
> Claus Windeler
>
>
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