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107 lines
3.4 KiB
Objective-C
107 lines
3.4 KiB
Objective-C
/* Copyright (c) 2006, 2010, Oracle and/or its affiliates. All rights reserved.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335 USA */
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#ifndef SQL_DELETE_INCLUDED
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#define SQL_DELETE_INCLUDED
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#include "my_base.h" /* ha_rows */
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#include "sql_class.h" /* enum_duplicates */
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#include "sql_cmd.h" // Sql_cmd_dml
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#include "sql_base.h"
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class THD;
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struct TABLE_LIST;
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class Item;
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class select_result;
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typedef class Item COND;
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template <typename T> class SQL_I_List;
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/**
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@class Sql_cmd_delete - class used for any DELETE statements
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This class is derived from Sql_cmd_dml and contains implementations
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for abstract virtual function of the latter such as precheck() and
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prepare_inner(). It also overrides the implementation of execute_inner()
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providing a special handling for single-table delete statements that
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are not converted to multi-table delete.
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The class provides an object of the DML_prelocking_strategy class
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for the virtual function get_dml_prelocking_strategy().
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*/
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class Sql_cmd_delete final : public Sql_cmd_dml
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{
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public:
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Sql_cmd_delete(bool multitable_arg)
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: orig_multitable(multitable_arg), multitable(multitable_arg),
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save_protocol(NULL)
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{}
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enum_sql_command sql_command_code() const override
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{
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return orig_multitable ? SQLCOM_DELETE_MULTI : SQLCOM_DELETE;
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}
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DML_prelocking_strategy *get_dml_prelocking_strategy() override
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{
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return &dml_prelocking_strategy;
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}
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bool processing_as_multitable_delete_prohibited(THD *thd);
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bool is_multitable() const { return multitable; }
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void set_as_multitable() { multitable= true; }
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void remove_order_by_without_limit(THD *thd);
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protected:
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/**
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@brief Perform precheck of table privileges for delete statements
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*/
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bool precheck(THD *thd) override;
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/**
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@brief Perform context analysis for delete statements
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*/
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bool prepare_inner(THD *thd) override;
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/**
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@brief Perform optimization and execution actions needed for deletes
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*/
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bool execute_inner(THD *thd) override;
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private:
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/**
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@biefSpecial handling of single-table deletes after prepare phase
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*/
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bool delete_from_single_table(THD *thd);
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/* Original value of the 'multitable' flag set by constructor */
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const bool orig_multitable;
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/*
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True if the statement is a multitable delete or converted to such.
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For a single-table delete this flag is set to true if the statement
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is supposed to be converted to multi-table delete.
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*/
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bool multitable;
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/* The prelocking strategy used when opening the used tables */
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DML_prelocking_strategy dml_prelocking_strategy;
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List<Item> empty_list; /**< auxiliary empty list used by prepare_inner() */
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Protocol *save_protocol; /**< needed for ANALYZE .. DELETE .. RETURNING */
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};
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#endif /* SQL_DELETE_INCLUDED */
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