As of PHP 3.0.1, you can use the constants ORA_BIND_INOUT, ORA_BIND_IN and ORA_BIND_OUT instead of the numbers.
This function binds the named PHP variable with a SQL parameter. The SQL parameter must be in the form ":name". With the optional type parameter, you can define whether the SQL parameter is an in/out (0, default), in (1) or out (2) parameter. As of PHP 3.0.1, you can use the constants ORA_BIND_INOUT, ORA_BIND_IN and ORA_BIND_OUT instead of the numbers.