Re: Multiple instances of mysql_connect() in single PHP document.

2009/11/11 Bastien Koert <phpster@gmail.com>: > On Tue, Nov 10, 2009 at 4:14 PM, Timothy Legg <php_list@timothylegg.com> wrote: >> >> Hello, >> >> Is it wrong to have mysql_connect() called twice within a single PHP >> document, such as this?  I have been running into some fairly annoying >> query failures that commute when I change the order of these two blocks of >> code.  I am currently working around this by repeatedly using >> mysql_select_db() to change the databases as I am needing to change to a >> different database. >> >> To be more specific, I can use the $db_material handle in doing a query, >> but it will always try to search in the Labor_Log table and thus fail >> because the tables have different and names.  Swapping these blocks will >> have a vice-versa effect. >> >> >>        //Connect to server (materials) >>        $db_material = mysql_connect("localhost", "root", >> "secret"); >>        if (!$db_material) >>        { >>                echo( "<P>Unable to connect to the database server at >> this >> time.</P>" ); >>                exit(); >>        } >>        mysql_select_db("Material_Log", $db_material); >> >> >>        //Connect to server (labor) >>        $db_labor = mysql_connect("localhost", "root", >> "secret"); >>        if (!$db_labor) >>        { >>                echo( "<P>Unable to connect to the database server at >> this >> time.</P>" ); >>                exit(); >>        } >>        mysql_select_db("Labor_Log", $db_labor); >> >> >> >> Tim Legg >> >> >> -- >> PHP Database Mailing List (http://www.php.net/) >> To unsubscribe, visit: http://www.php.net/unsub.php >> >> > > If the databases are in the same mysql server, then you could qualify > the table select with the database name and simply re-use the > connection > > select db_name.table_name.field from db_name.table_name [where] > > > -- > > Bastien > > Cat, the other other white meat > > -- > PHP Database Mailing List (http://www.php.net/) > To unsubscribe, visit: http://www.php.net/unsub.php > > As I understand things, if you make 2 or more connections to the same database server with the same credentials, you end up with 1 shared connection. This is assuming you are not using mysql_pconnect() and you are not using the new_link option on mysql_connect(). See http://svn.php.net/viewvc/php/php-src/trunk/ext/mysql/php_mysql.c?view=markup#l864. If you then use change DB on one of the connection, you are changing it for both. The answer is to use a single connection and a fully qualified name to the table. SELECT Alias.Column FROM Database.Table.Column AS Alias sort of thing. -- ----- Richard Quadling "Standing on the shoulders of some very clever giants!" EE : http://www.experts-exchange.com/M_248814.html Zend Certified Engineer : http://zend.com/zce.php?c=ZEND002498&r=213474731 ZOPA : http://uk.zopa.com/member/RQuadling