CI_DB_query_builder::update_batch PHP Method

    public function update_batch($table, $set = NULL, $index = NULL, $batch_size = 100)
    {
        // Combine any cached components with the current statements
        $this->_merge_cache();
        if ($index === NULL) {
            return $this->db_debug ? $this->display_error('db_must_use_index') : FALSE;
        }
        if ($set === NULL) {
            if (empty($this->qb_set)) {
                return $this->db_debug ? $this->display_error('db_must_use_set') : FALSE;
            }
        } else {
            if (empty($set)) {
                return $this->db_debug ? $this->display_error('update_batch() called with no data') : FALSE;
            }
            $this->set_update_batch($set, $index);
        }
        if (strlen($table) === 0) {
            if (!isset($this->qb_from[0])) {
                return $this->db_debug ? $this->display_error('db_must_set_table') : FALSE;
            }
            $table = $this->qb_from[0];
        }
        // Batch this baby
        $affected_rows = 0;
        for ($i = 0, $total = count($this->qb_set); $i < $total; $i += $batch_size) {
            $this->query($this->_update_batch($this->protect_identifiers($table, TRUE, NULL, FALSE), array_slice($this->qb_set, $i, $batch_size), $this->protect_identifiers($index)));
            $affected_rows += $this->affected_rows();
            $this->qb_where = array();
        }
        $this->_reset_write();
        return $affected_rows;
    }