Method send_data

sql/sql_update.cc:2405–2583

int multi_update::send_data(List<Item> &not_used_values)
{
  TABLE_LIST *cur_table;
  DBUG_ENTER("multi_update::send_data");

  for (cur_table= update_tables; cur_table; cur_table= cur_table->next_local)
  {
    int error= 0;
    TABLE *table= cur_table->table;
    uint offset= cur_table->shared;
    /*
      Check if we are using outer join and we didn't find the row
      or if we have already updated this row in the previous call to this
      function.

      The same row may be presented here several times in a join of type
      UPDATE t1 FROM t1,t2 SET t1.a=t2.a

      In this case we will do the update for the first found row combination.
      The join algorithm guarantees that we will not find the a row in
      t1 several times.
    */
    if (table->status & (STATUS_NULL_ROW | STATUS_UPDATED))
      continue;

    if (table == table_to_update)
    {
      /*
        We can use compare_record() to optimize away updates if
        the table handler is returning all columns OR if
        if all updated columns are read
      */
      bool can_compare_record;
      can_compare_record= records_are_comparable(table);

      table->status|= STATUS_UPDATED;
      store_record(table,record[1]);

      bool trg_skip_row= false;
      if (fill_record_n_invoke_before_triggers(thd, table,
                                               *fields_for_table[offset],
                                               *values_for_table[offset], 0,
                                               TRG_EVENT_UPDATE,
                                               &trg_skip_row))
	DBUG_RETURN(1);

      if (trg_skip_row)
        continue;

      /*
        Reset the table->auto_increment_field_not_null as it is valid for
        only one row.
      */
      table->auto_increment_field_not_null= FALSE;
      found++;
      if (!can_compare_record || compare_record(table))
      {