PDO::PARAM_LOB (value=3) overlaps with PDO::FETCH_NUM (value=3) in OCI8Statement::$fetchModeMap

Hi,

In OCI8Statement, using PDO::FETCH_NUM does not work because the fetch style mapping is overwritten by PDO::PARAM_LOB since the two has the same value (3);

protected static $fetchModeMap = array(
PDO::FETCH_BOTH => OCI_BOTH,
PDO::FETCH_ASSOC => OCI_ASSOC,
PDO::FETCH_NUM => OCI_NUM,
PDO::PARAM_LOB => OCI_B_BLOB,
PDO::FETCH_COLUMN => OCI_NUM,
);

so PDO::FETCH_NUM is mapped to OCI_B_BLOB