Multiple database access Bug in adoDB and It's Solution

[CountDraculla]

Fixing Multiple Database bug in adoDB

popular data access layer for php, adoDB can support multiple databases
from different provider at time, but not from same provider. what I
mean is if you instantiate two adoDB connection like this

$db1 = &NewAdoConnecti on ("mysql");
$db1 = &NewAdoConnecti on ("oracle");

then you can run queries simultaneously from these connections. but if
you want to access two database from same provider like this

$db1 = &NewAdoConnecti on ("mysql");
$db1 = &NewAdoConnecti on ("mysql");
$db1->PConnect(login info_for_first_ database)
$db2->PConnect(login info_for_second _database)

then only last action will remain active and if you use
$db1->execute(), it will actually works on second database. if you want
to access any table from first database, it will generate an error. I
think this is an internal bug in adoDB.

How to fix this bug?

if you open adodb-mysql.inc.php and goto function _connect() you will
find this line at the end

1. if ($argDatabasena me) return $this->SelectDB($argD atabasename);

now goto SelectDB function and see what it contains actually.

// returns true or false
function SelectDB($dbNam e)
{
$this->databaseName = $dbName;
if ($this->_connectionI D) {
return @mysql_select_d b($dbName,$this->_connectionID) ;
}
else return false;
}

so it basically returns a boolean value, mysql connection link is
stored in $this->_connectionI D variable. Now modify this code like this

1. add this line at the declaration section of adodb-mysql.inc.php

var $__db = array();

2. modify the SelectDB function like this

// returns true or false
function SelectDB($dbNam e)
{
$this->databaseName = $dbName;
if ($this->_connectionI D) {
@mysql_select_d b($dbName,$this->_connectionID) ;
$this->__db[$this->_connectionI D] = $dbName;
return $this->_connectionI D;
}
else return false;
}

3. Now open the _query function and modify it like this

// returns queryID or false
function _query($sql,$in putarr)
{
//global $ADODB_COUNTREC S;
//if($ADODB_COUNT RECS)
$this->SelectDB($th is->__db[$this->_connectionI D]);
return mysql_query($sq l, $this->_connectionID) ;
//else return @mysql_unbuffer ed_query($sql,$ this->_connectionID) ;
// requires PHP >= 4.0.6
}

That's it!!, now your adoDB supports multiple databases from same
provider.

Thanks
Hasin Hayder
http ://groups.yahoo.co m/group.phpexpert s