mariadb/sql/sql_update.h

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2011-06-30 17:46:53 +02:00
/* Copyright (c) 2006, 2010, Oracle and/or its affiliates. All rights reserved.
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; version 2 of the License.
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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335 USA */
#ifndef SQL_UPDATE_INCLUDED
#define SQL_UPDATE_INCLUDED
#include "sql_class.h" /* enum_duplicates */
MDEV-28883 Re-design the upper level of handling UPDATE and DELETE statements This patch introduces a new way of handling UPDATE and DELETE commands at the top level after the parsing phase. This new way of processing update and delete statements can be seen in the implementation of the prepare() and execute() methods from the new Sql_cmd_dml class. This class derived from the Sql_cmd class can be considered as an interface class for processing such commands as SELECT, INSERT, UPDATE, DELETE and other comands manipulating data in tables. With this patch processing of update and delete statements after parsing proceeds by the following schema: - precheck of the access rights is performed for the used tables - the used tables are opened - context analysis phase is performed for the statement - the used tables are locked - the statement is optimized and executed - clean-up is performed for the statement The implementation of the method Sql_cmd_dml::execute() adheres this schema. The virtual functions of the class Sql_cmd_dml used for precheck of the access rights, context analysis, optimization and execution allow to adjust this schema for processing data manipulation statements of any types. This schema of processing data manipulation statements is taken from the current MySQL code. Moreover the definition the class Sql_cmd_dml introduced in this patch is almost a full replica of such class in the existing MySQL. However the implementation of the derived classes for update and delete statements is quite different. This implementation employs the JOIN class for all kinds of update and delete statements. It allows to perform main bulk of context analysis actions by the function JOIN::prepare(). This guarantees that characteristics and properties of the statement tree discovered for optimization phase when doing context analysis are the same for single-table and multi-table updates and deletes. With this patch the following functions are gone: mysql_prepare_update(), mysql_multi_update_prepare(), mysql_update(), mysql_multi_update(), mysql_prepare_delete(), mysql_multi_delete_prepare(), mysql_delete(). The code within these functions have been used as much as possible though. The functions mysql_test_update() and mysql_test_delete() are also not needed anymore. The method Sql_cmd_dml::prepare() serves processing - update/delete statement - PREPARE stmt FROM "<update/delete statement>" - EXECUTE stmt when stmt is prepared from update/delete statement. Approved by Oleksandr Byelkin <sanja@mariadb.com>
2022-06-18 16:28:48 -07:00
#include "sql_cmd.h" // Sql_cmd_dml
#include "sql_base.h"
class Item;
struct TABLE_LIST;
class THD;
typedef class st_select_lex SELECT_LEX;
typedef class st_select_lex_unit SELECT_LEX_UNIT;
bool check_unique_table(THD *thd, TABLE_LIST *table_list);
bool records_are_comparable(const TABLE *table);
bool compare_record(const TABLE *table);
MDEV-28883 Re-design the upper level of handling UPDATE and DELETE statements This patch introduces a new way of handling UPDATE and DELETE commands at the top level after the parsing phase. This new way of processing update and delete statements can be seen in the implementation of the prepare() and execute() methods from the new Sql_cmd_dml class. This class derived from the Sql_cmd class can be considered as an interface class for processing such commands as SELECT, INSERT, UPDATE, DELETE and other comands manipulating data in tables. With this patch processing of update and delete statements after parsing proceeds by the following schema: - precheck of the access rights is performed for the used tables - the used tables are opened - context analysis phase is performed for the statement - the used tables are locked - the statement is optimized and executed - clean-up is performed for the statement The implementation of the method Sql_cmd_dml::execute() adheres this schema. The virtual functions of the class Sql_cmd_dml used for precheck of the access rights, context analysis, optimization and execution allow to adjust this schema for processing data manipulation statements of any types. This schema of processing data manipulation statements is taken from the current MySQL code. Moreover the definition the class Sql_cmd_dml introduced in this patch is almost a full replica of such class in the existing MySQL. However the implementation of the derived classes for update and delete statements is quite different. This implementation employs the JOIN class for all kinds of update and delete statements. It allows to perform main bulk of context analysis actions by the function JOIN::prepare(). This guarantees that characteristics and properties of the statement tree discovered for optimization phase when doing context analysis are the same for single-table and multi-table updates and deletes. With this patch the following functions are gone: mysql_prepare_update(), mysql_multi_update_prepare(), mysql_update(), mysql_multi_update(), mysql_prepare_delete(), mysql_multi_delete_prepare(), mysql_delete(). The code within these functions have been used as much as possible though. The functions mysql_test_update() and mysql_test_delete() are also not needed anymore. The method Sql_cmd_dml::prepare() serves processing - update/delete statement - PREPARE stmt FROM "<update/delete statement>" - EXECUTE stmt when stmt is prepared from update/delete statement. Approved by Oleksandr Byelkin <sanja@mariadb.com>
2022-06-18 16:28:48 -07:00
/**
@class Sql_cmd_update - class used for any UPDATE statements
This class is derived from Sql_cmd_dml and contains implementations
for abstract virtual function of the latter such as precheck() and
prepare_inner(). It also overrides the implementation of execute_inner()
providing a special handling for single-table update statements that
are not converted to multi-table updates.
The class provides an object of the Multiupdate_prelocking_strategy class
for the virtual function get_dml_prelocking_strategy().
*/
class Sql_cmd_update final : public Sql_cmd_dml
{
public:
Sql_cmd_update(bool multitable_arg)
: orig_multitable(multitable_arg), multitable(multitable_arg)
{}
MDEV-28883 Re-design the upper level of handling UPDATE and DELETE statements This patch introduces a new way of handling UPDATE and DELETE commands at the top level after the parsing phase. This new way of processing update and delete statements can be seen in the implementation of the prepare() and execute() methods from the new Sql_cmd_dml class. This class derived from the Sql_cmd class can be considered as an interface class for processing such commands as SELECT, INSERT, UPDATE, DELETE and other comands manipulating data in tables. With this patch processing of update and delete statements after parsing proceeds by the following schema: - precheck of the access rights is performed for the used tables - the used tables are opened - context analysis phase is performed for the statement - the used tables are locked - the statement is optimized and executed - clean-up is performed for the statement The implementation of the method Sql_cmd_dml::execute() adheres this schema. The virtual functions of the class Sql_cmd_dml used for precheck of the access rights, context analysis, optimization and execution allow to adjust this schema for processing data manipulation statements of any types. This schema of processing data manipulation statements is taken from the current MySQL code. Moreover the definition the class Sql_cmd_dml introduced in this patch is almost a full replica of such class in the existing MySQL. However the implementation of the derived classes for update and delete statements is quite different. This implementation employs the JOIN class for all kinds of update and delete statements. It allows to perform main bulk of context analysis actions by the function JOIN::prepare(). This guarantees that characteristics and properties of the statement tree discovered for optimization phase when doing context analysis are the same for single-table and multi-table updates and deletes. With this patch the following functions are gone: mysql_prepare_update(), mysql_multi_update_prepare(), mysql_update(), mysql_multi_update(), mysql_prepare_delete(), mysql_multi_delete_prepare(), mysql_delete(). The code within these functions have been used as much as possible though. The functions mysql_test_update() and mysql_test_delete() are also not needed anymore. The method Sql_cmd_dml::prepare() serves processing - update/delete statement - PREPARE stmt FROM "<update/delete statement>" - EXECUTE stmt when stmt is prepared from update/delete statement. Approved by Oleksandr Byelkin <sanja@mariadb.com>
2022-06-18 16:28:48 -07:00
enum_sql_command sql_command_code() const override
{
return orig_multitable ? SQLCOM_UPDATE_MULTI : SQLCOM_UPDATE;
MDEV-28883 Re-design the upper level of handling UPDATE and DELETE statements This patch introduces a new way of handling UPDATE and DELETE commands at the top level after the parsing phase. This new way of processing update and delete statements can be seen in the implementation of the prepare() and execute() methods from the new Sql_cmd_dml class. This class derived from the Sql_cmd class can be considered as an interface class for processing such commands as SELECT, INSERT, UPDATE, DELETE and other comands manipulating data in tables. With this patch processing of update and delete statements after parsing proceeds by the following schema: - precheck of the access rights is performed for the used tables - the used tables are opened - context analysis phase is performed for the statement - the used tables are locked - the statement is optimized and executed - clean-up is performed for the statement The implementation of the method Sql_cmd_dml::execute() adheres this schema. The virtual functions of the class Sql_cmd_dml used for precheck of the access rights, context analysis, optimization and execution allow to adjust this schema for processing data manipulation statements of any types. This schema of processing data manipulation statements is taken from the current MySQL code. Moreover the definition the class Sql_cmd_dml introduced in this patch is almost a full replica of such class in the existing MySQL. However the implementation of the derived classes for update and delete statements is quite different. This implementation employs the JOIN class for all kinds of update and delete statements. It allows to perform main bulk of context analysis actions by the function JOIN::prepare(). This guarantees that characteristics and properties of the statement tree discovered for optimization phase when doing context analysis are the same for single-table and multi-table updates and deletes. With this patch the following functions are gone: mysql_prepare_update(), mysql_multi_update_prepare(), mysql_update(), mysql_multi_update(), mysql_prepare_delete(), mysql_multi_delete_prepare(), mysql_delete(). The code within these functions have been used as much as possible though. The functions mysql_test_update() and mysql_test_delete() are also not needed anymore. The method Sql_cmd_dml::prepare() serves processing - update/delete statement - PREPARE stmt FROM "<update/delete statement>" - EXECUTE stmt when stmt is prepared from update/delete statement. Approved by Oleksandr Byelkin <sanja@mariadb.com>
2022-06-18 16:28:48 -07:00
}
DML_prelocking_strategy *get_dml_prelocking_strategy() override
MDEV-28883 Re-design the upper level of handling UPDATE and DELETE statements This patch introduces a new way of handling UPDATE and DELETE commands at the top level after the parsing phase. This new way of processing update and delete statements can be seen in the implementation of the prepare() and execute() methods from the new Sql_cmd_dml class. This class derived from the Sql_cmd class can be considered as an interface class for processing such commands as SELECT, INSERT, UPDATE, DELETE and other comands manipulating data in tables. With this patch processing of update and delete statements after parsing proceeds by the following schema: - precheck of the access rights is performed for the used tables - the used tables are opened - context analysis phase is performed for the statement - the used tables are locked - the statement is optimized and executed - clean-up is performed for the statement The implementation of the method Sql_cmd_dml::execute() adheres this schema. The virtual functions of the class Sql_cmd_dml used for precheck of the access rights, context analysis, optimization and execution allow to adjust this schema for processing data manipulation statements of any types. This schema of processing data manipulation statements is taken from the current MySQL code. Moreover the definition the class Sql_cmd_dml introduced in this patch is almost a full replica of such class in the existing MySQL. However the implementation of the derived classes for update and delete statements is quite different. This implementation employs the JOIN class for all kinds of update and delete statements. It allows to perform main bulk of context analysis actions by the function JOIN::prepare(). This guarantees that characteristics and properties of the statement tree discovered for optimization phase when doing context analysis are the same for single-table and multi-table updates and deletes. With this patch the following functions are gone: mysql_prepare_update(), mysql_multi_update_prepare(), mysql_update(), mysql_multi_update(), mysql_prepare_delete(), mysql_multi_delete_prepare(), mysql_delete(). The code within these functions have been used as much as possible though. The functions mysql_test_update() and mysql_test_delete() are also not needed anymore. The method Sql_cmd_dml::prepare() serves processing - update/delete statement - PREPARE stmt FROM "<update/delete statement>" - EXECUTE stmt when stmt is prepared from update/delete statement. Approved by Oleksandr Byelkin <sanja@mariadb.com>
2022-06-18 16:28:48 -07:00
{
return &multiupdate_prelocking_strategy;
}
bool processing_as_multitable_update_prohibited(THD *thd);
bool is_multitable() const { return multitable; }
void set_as_multitable() { multitable= true; }
MDEV-28883 Re-design the upper level of handling UPDATE and DELETE statements This patch introduces a new way of handling UPDATE and DELETE commands at the top level after the parsing phase. This new way of processing update and delete statements can be seen in the implementation of the prepare() and execute() methods from the new Sql_cmd_dml class. This class derived from the Sql_cmd class can be considered as an interface class for processing such commands as SELECT, INSERT, UPDATE, DELETE and other comands manipulating data in tables. With this patch processing of update and delete statements after parsing proceeds by the following schema: - precheck of the access rights is performed for the used tables - the used tables are opened - context analysis phase is performed for the statement - the used tables are locked - the statement is optimized and executed - clean-up is performed for the statement The implementation of the method Sql_cmd_dml::execute() adheres this schema. The virtual functions of the class Sql_cmd_dml used for precheck of the access rights, context analysis, optimization and execution allow to adjust this schema for processing data manipulation statements of any types. This schema of processing data manipulation statements is taken from the current MySQL code. Moreover the definition the class Sql_cmd_dml introduced in this patch is almost a full replica of such class in the existing MySQL. However the implementation of the derived classes for update and delete statements is quite different. This implementation employs the JOIN class for all kinds of update and delete statements. It allows to perform main bulk of context analysis actions by the function JOIN::prepare(). This guarantees that characteristics and properties of the statement tree discovered for optimization phase when doing context analysis are the same for single-table and multi-table updates and deletes. With this patch the following functions are gone: mysql_prepare_update(), mysql_multi_update_prepare(), mysql_update(), mysql_multi_update(), mysql_prepare_delete(), mysql_multi_delete_prepare(), mysql_delete(). The code within these functions have been used as much as possible though. The functions mysql_test_update() and mysql_test_delete() are also not needed anymore. The method Sql_cmd_dml::prepare() serves processing - update/delete statement - PREPARE stmt FROM "<update/delete statement>" - EXECUTE stmt when stmt is prepared from update/delete statement. Approved by Oleksandr Byelkin <sanja@mariadb.com>
2022-06-18 16:28:48 -07:00
protected:
/**
@brief Perform precheck of table privileges for update statements
*/
bool precheck(THD *thd) override;
/**
@brief Perform context analysis for update statements
*/
bool prepare_inner(THD *thd) override;
/**
@brief Perform optimization and execution actions needed for updates
*/
bool execute_inner(THD *thd) override;
private:
/**
@brief Special handling of single-table updates after prepare phase
*/
bool update_single_table(THD *thd);
/* Original value of the 'multitable' flag set by constructor */
const bool orig_multitable;
MDEV-28883 Re-design the upper level of handling UPDATE and DELETE statements This patch introduces a new way of handling UPDATE and DELETE commands at the top level after the parsing phase. This new way of processing update and delete statements can be seen in the implementation of the prepare() and execute() methods from the new Sql_cmd_dml class. This class derived from the Sql_cmd class can be considered as an interface class for processing such commands as SELECT, INSERT, UPDATE, DELETE and other comands manipulating data in tables. With this patch processing of update and delete statements after parsing proceeds by the following schema: - precheck of the access rights is performed for the used tables - the used tables are opened - context analysis phase is performed for the statement - the used tables are locked - the statement is optimized and executed - clean-up is performed for the statement The implementation of the method Sql_cmd_dml::execute() adheres this schema. The virtual functions of the class Sql_cmd_dml used for precheck of the access rights, context analysis, optimization and execution allow to adjust this schema for processing data manipulation statements of any types. This schema of processing data manipulation statements is taken from the current MySQL code. Moreover the definition the class Sql_cmd_dml introduced in this patch is almost a full replica of such class in the existing MySQL. However the implementation of the derived classes for update and delete statements is quite different. This implementation employs the JOIN class for all kinds of update and delete statements. It allows to perform main bulk of context analysis actions by the function JOIN::prepare(). This guarantees that characteristics and properties of the statement tree discovered for optimization phase when doing context analysis are the same for single-table and multi-table updates and deletes. With this patch the following functions are gone: mysql_prepare_update(), mysql_multi_update_prepare(), mysql_update(), mysql_multi_update(), mysql_prepare_delete(), mysql_multi_delete_prepare(), mysql_delete(). The code within these functions have been used as much as possible though. The functions mysql_test_update() and mysql_test_delete() are also not needed anymore. The method Sql_cmd_dml::prepare() serves processing - update/delete statement - PREPARE stmt FROM "<update/delete statement>" - EXECUTE stmt when stmt is prepared from update/delete statement. Approved by Oleksandr Byelkin <sanja@mariadb.com>
2022-06-18 16:28:48 -07:00
/*
True if the statement is a multi-table update or converted to such.
For a single-table update this flag is set to true if the statement
is supposed to be converted to multi-table update.
*/
bool multitable;
/* The prelocking strategy used when opening the used tables */
Multiupdate_prelocking_strategy multiupdate_prelocking_strategy;
public:
/* The list of the updating expressions used in the set clause */
List<Item> *update_value_list;
};
#endif /* SQL_UPDATE_INCLUDED */