When you start Apache with PHP built with ODBC support, PHP immediately allocates an ODBC environment handle. Unfortunately, the OOB searches for the odbc.ini file when an environment handle is created and so your odbc.ini file needs to found at server startup. This can be a nuisance since most people start Apache at machine boot time from an rc script but locate their odbc.ini files in the same directory as their PHP scripts. The best way around this is to put all your DSN definitions in the /etc/odbc.ini (or SYS$ROOT:odbc.ini for VMS) file.
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