item_row.cpp
上传用户:romrleung
上传日期:2022-05-23
资源大小:18897k
文件大小:4k
- /* Copyright (C) 2000 MySQL AB
- This program is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2 of the License, or
- (at your option) any later version.
- This program is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
- You should have received a copy of the GNU General Public License
- along with this program; if not, write to the Free Software
- Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
- #include "mysql_priv.h"
- /*
- Row items used for comparing rows and IN operations on rows:
- (a, b, c) > (10, 10, 30)
- (a, b, c) = (select c, d, e, from t1 where x=12)
- (a, b, c) IN ((1,2,2), (3,4,5), (6,7,8)
- (a, b, c) IN (select c, d, e, from t1)
- */
- Item_row::Item_row(List<Item> &arg):
- Item(), used_tables_cache(0), array_holder(1), const_item_cache(1), with_null(0)
- {
- //TODO: think placing 2-3 component items in item (as it done for function)
- if ((arg_count= arg.elements))
- items= (Item**) sql_alloc(sizeof(Item*)*arg_count);
- else
- items= 0;
- List_iterator<Item> li(arg);
- uint i= 0;
- Item *item;
- while ((item= li++))
- {
- items[i]= item;
- i++;
- }
- }
- void Item_row::illegal_method_call(const char *method)
- {
- DBUG_ENTER("Item_row::illegal_method_call");
- DBUG_PRINT("error", ("!!! %s method was called for row item", method));
- DBUG_ASSERT(0);
- my_error(ER_OPERAND_COLUMNS, MYF(0), 1);
- DBUG_VOID_RETURN;
- }
- bool Item_row::fix_fields(THD *thd, TABLE_LIST *tabl, Item **ref)
- {
- DBUG_ASSERT(fixed == 0);
- null_value= 0;
- maybe_null= 0;
- Item **arg, **arg_end;
- for (arg= items, arg_end= items+arg_count; arg != arg_end ; arg++)
- {
- if ((*arg)->fix_fields(thd, tabl, arg))
- return 1;
- // we can't assign 'item' before, because fix_fields() can change arg
- Item *item= *arg;
- used_tables_cache |= item->used_tables();
- const_item_cache&= item->const_item() && !with_null;
- if (const_item_cache)
- {
- if (item->cols() > 1)
- with_null|= item->null_inside();
- else
- {
- item->val_int();
- with_null|= item->null_value;
- }
- }
- maybe_null|= item->maybe_null;
- with_sum_func= with_sum_func || item->with_sum_func;
- }
- fixed= 1;
- return 0;
- }
- void Item_row::split_sum_func(THD *thd, Item **ref_pointer_array,
- List<Item> &fields)
- {
- Item **arg, **arg_end;
- for (arg= items, arg_end= items+arg_count; arg != arg_end ; arg++)
- (*arg)->split_sum_func2(thd, ref_pointer_array, fields, arg);
- }
- void Item_row::update_used_tables()
- {
- used_tables_cache= 0;
- const_item_cache= 1;
- for (uint i= 0; i < arg_count; i++)
- {
- items[i]->update_used_tables();
- used_tables_cache|= items[i]->used_tables();
- const_item_cache&= items[i]->const_item();
- }
- }
- bool Item_row::check_cols(uint c)
- {
- if (c != arg_count)
- {
- my_error(ER_OPERAND_COLUMNS, MYF(0), c);
- return 1;
- }
- return 0;
- }
- void Item_row::print(String *str)
- {
- str->append('(');
- for (uint i= 0; i < arg_count; i++)
- {
- if (i)
- str->append(',');
- items[i]->print(str);
- }
- str->append(')');
- }
- bool Item_row::walk(Item_processor processor, byte *arg)
- {
- for (uint i= 0; i < arg_count; i++)
- {
- if (items[i]->walk(processor, arg))
- return 1;
- }
- return (this->*processor)(arg);
- }
- void Item_row::bring_value()
- {
- for (uint i= 0; i < arg_count; i++)
- items[i]->bring_value();
- }