/**
 * Returns the proper SQL to do LIKE in a case-insensitive way for oracle
 * and Postgres
 * 
 * Note the LIKE are case sensitive for Oracle. Oracle 10g is required to use
 * the caseinsensitive search using regexp_like() or NLS_COMP=LINGUISTIC :-(
 * See http://docs.moodle.org/en/XMLDB_Problems#Case-insensitive_searches
 *
 * @uses $CFG
 * @param string $field Number of records per page
 * @param string $data Number of records per page
 * @param integer $operator Number of records per page
 * @return string
 */
function sql_olike($field, $data, $operator=0) {
    global $CFG;
    $not = '';

    switch ($operator) {
        case 0: // contains
            $value = "'%$data%'";
            $oci8_value = "'$data'";
            break;
        case 1: // does not contain
            $not = 'NOT';
            $value = "'%$data%'";
            $oci8_value = "'$data'";
            break;
        case 2: // equal to
            $value = "'$data'";
            $oci8_value = "'^$data$'";
            break;
        case 3: // starts with
            $value = "'$data%'";
            $oci8_value = "'^$data'";
            break;
        case 4: // ends with
            $value = "'%$data'";
            $oci8_value = "'$data$'";
            break;
        case 5: // empty
            $value = "''";
            $oci8_value = "''";
            break;
        case 7: // is defined
            break;
    }

    switch ($CFG->dbfamily) {
        case 'postgres':
             return " $field $not ILIKE $value ";
        case 'oracle':
            return "$not regexp_like($field, $oci8_value, 'i') ";
        default:
             return " $field $not LIKE $value ";
    }
}