Re: A strange question about mysql_close()

2009/12/17 唐家兴 <tjxing.1988@gmail.com>: > I want to ask a strange question. > > As we know, if we connect a mysql database in the same host twice with the > same username, we won't get two new link, but two handle to only one link.. > Then, if I close one of them, whether the other one will be closed together? > > I wrote two pieces of code. The first is like this > <?php > $db1 = mysql_connect($host, $username, $pwd); > $db2 = mysql_connect($host, $username, $pwd); > $sql = 'show databases'; > mysql_close($db1); > $res = mysql_query($sql, $db2); > $a = mysql_fetch_row($res); > print_r($a); > ?> > Then the output of the $db2 is correct. So the $db2 isn't closed together > with the $db1. > > But when I add a line among the code, the result is different > <?php > $db1 = mysql_connect($host, $username, $pwd); > $db2 = mysql_connect($host, $username, $pwd); > $sql = 'show databases'; > mysql_close($db1); > $db1 = true; //a new line > $res = mysql_query($sql, $db2); > $a = mysql_fetch_row($res); > print_r($a); > ?> > Then the output is wrong. The PHP tell me that the link is not a valid one. > I don't know how an assignment operation for the $db1 can close the $db2. > Could someone help me. > I'll appreciate your help. > When you xxx_connect() with the same parameters, internally, you are sharing the connection. It seems that killing one of the references kills all the references. The solution is to a use the fourth parameter on mysql_connect(). The "new_link" param. So ... <?php $db1 = mysql_connect($host, $username, $pwd, True); // Make sure a new link is created. $db2 = mysql_connect($host, $username, $pwd, True); // Make sure a new link is created. $sql = 'show databases'; mysql_close($db1); $db1 = true; //a new line $res = mysql_query($sql, $db2); $a = mysql_fetch_row($res); print_r($a); ?> should work. -- ----- 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