To connect to a SQL DB on a unix srv via odbc one can use one of the following solutions.

1. having an odbc.ini (~/.odbc.ini)

[PostgreSQL]
Description         = PostgreSQL template1
Driver              = PostgreSQL
Trace               = Yes
TraceFile           = /tmp/odbc.log
Database            = PerfTest
Servername          = localhost
UserName            = boss
Password            = BigBoss
Port                = 5432
Protocol            = 6.4
ReadOnly            = Yes
ConnSettings        =

[Default]
Driver = /local/lib/libodbc.so

2. specifying a DSN 

function DBCALL($SQL)
{        
$U = "boss";
$DB = "PerfTest";
$P = "BigBoss";
$Srv = "llocalhost";
$DSN = "Driver=PostgreSQL;Server=$Srv;Database=$DB";
        
echo "Trying to connect to $DSN\n";    
if ($CID = odbc_connect ("$DSN","$U","$P",SQL_CUR_USE_ODBC))
{
    echo "still trying CID = $CID\n";
    if ($RES = odbc_exec($CID, $SQL))
    {
        echo "RES = $RES\n";
        print_r($RES);
        echo "\n";
            
        $NR = odbc_num_rows($RES);

<snip>

Hope this helps.