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Posted by Jim Michaels on 03/19/06 07:18
"Chung Leong" <chernyshevsky@hotmail.com> wrote in message
news:1142704883.623831.317580@z34g2000cwc.googlegroups.com...
>
> Jim Michaels wrote:
>> Is it safe to do what is below? deleting from a resultset while you are
>> processing it? I don't know how dynamic the SQL database is. I assume
>> you
>> get a cursor to live dataset. Even if it is a cursor as opposed to a
>> table,
>> will the cursor's integrity be ruined if the current record is deleted?
>>
>> $q2=mysql_query("SELECT * FROM table1 WHERE id1=5", $link);
>> while ($row2=mysql_fetch_array($q2)) {
>> //do some stuff with resultset
>> mysql_query("DELETE FROM table1 WHERE id1=5 AND id2=$row2[id2]",
>> $link);
>> }
>> mysql_free_result($q2);
>
> With MySQL I believe it's safe, as the client buffers the whole result
> set. It's more efficient though to save the ids into an array, then
> delete all the applicable rows in a single operation with a "id2 IN (
> ... )" condition.
>
thx for the tip. Hadn't thought of that. Makes sense.
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