1 /* Copyright (c) 2006, 2020, Oracle and/or its affiliates. All rights reserved. 2 3 This program is free software; you can redistribute it and/or modify 4 it under the terms of the GNU General Public License, version 2.0, 5 as published by the Free Software Foundation. 6 7 This program is also distributed with certain software (including 8 but not limited to OpenSSL) that is licensed under separate terms, 9 as designated in a particular file or component or in included license 10 documentation. The authors of MySQL hereby grant you an additional 11 permission to link the program and your derivative works with the 12 separately licensed software that they have included with MySQL. 13 14 This program is distributed in the hope that it will be useful, 15 but WITHOUT ANY WARRANTY; without even the implied warranty of 16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 GNU General Public License, version 2.0, for more details. 18 19 You should have received a copy of the GNU General Public License 20 along with this program; if not, write to the Free Software 21 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */ 22 23 #ifndef SQL_UPDATE_INCLUDED 24 #define SQL_UPDATE_INCLUDED 25 26 #include <stddef.h> 27 #include <sys/types.h> 28 29 #include "my_base.h" 30 #include "my_sqlcommand.h" 31 #include "sql/query_result.h" // Query_result_interceptor 32 #include "sql/sql_cmd_dml.h" // Sql_cmd_dml 33 #include "sql/sql_list.h" 34 35 class COPY_INFO; 36 class Copy_field; 37 class Item; 38 class SELECT_LEX_UNIT; 39 class Select_lex_visitor; 40 class THD; 41 class Temp_table_param; 42 struct TABLE; 43 struct TABLE_LIST; 44 45 bool records_are_comparable(const TABLE *table); 46 bool compare_records(const TABLE *table); 47 bool should_switch_to_multi_table_if_subqueries(const THD *thd, 48 const SELECT_LEX *select, 49 const TABLE_LIST *table_list); 50 51 class Query_result_update final : public Query_result_interceptor { 52 /// Number of tables being updated 53 uint update_table_count; 54 /// Pointer to list of updated tables, linked via 'next_local' 55 TABLE_LIST *update_tables; 56 /// Array of references to temporary tables used to store cached updates 57 TABLE **tmp_tables; 58 /// Array of parameter structs for creation of temporary tables 59 Temp_table_param *tmp_table_param; 60 /// The first table in the join operation 61 TABLE *main_table; 62 /** 63 In a multi-table update, this is equal to the first table in the join 64 operation (#main_table) if that table can be updated on the fly while 65 scanning it. It is `nullptr` otherwise. 66 67 @see safe_update_on_fly 68 */ 69 TABLE *table_to_update; 70 /// Number of rows found that matches join and WHERE conditions 71 ha_rows found_rows; 72 /// Number of rows actually updated, in all affected tables 73 ha_rows updated_rows; 74 /// List of pointers to fields to update, in order from statement 75 List<Item> *fields; 76 /// List of pointers to values to update with, in order from statement 77 List<Item> *values; 78 /// The fields list decomposed into separate lists per table 79 List<Item> **fields_for_table; 80 /// The values list decomposed into separate lists per table 81 List<Item> **values_for_table; 82 /** 83 List of tables referenced in the CHECK OPTION condition of 84 the updated view excluding the updated table. 85 */ 86 List<TABLE> unupdated_check_opt_tables; 87 /// ??? 88 Copy_field *copy_field; 89 /// Length of the copy_field array. 90 size_t max_fields{0}; 91 /// True if the full update operation is complete 92 bool update_completed; 93 /// True if all tables to be updated are transactional. 94 bool trans_safe; 95 /// True if the update operation has made a change in a transactional table 96 bool transactional_tables; 97 /** 98 error handling (rollback and binlogging) can happen in send_eof() 99 so that afterward send_error() needs to find out that. 100 */ 101 bool error_handled; 102 103 /** 104 Array of update operations, arranged per _updated_ table. For each 105 _updated_ table in the multiple table update statement, a COPY_INFO 106 pointer is present at the table's position in this array. 107 108 The array is allocated and populated during Query_result_update::prepare(). 109 The position that each table is assigned is also given here and is stored 110 in the member TABLE::pos_in_table_list::shared. However, this is a publicly 111 available field, so nothing can be trusted about its integrity. 112 113 This member is NULL when the Query_result_update is created. 114 115 @see Query_result_update::prepare 116 */ 117 COPY_INFO **update_operations; 118 119 public: Query_result_update(List<Item> * field_list,List<Item> * value_list)120 Query_result_update(List<Item> *field_list, List<Item> *value_list) 121 : Query_result_interceptor(), 122 update_table_count(0), 123 update_tables(nullptr), 124 tmp_tables(nullptr), 125 main_table(nullptr), 126 table_to_update(nullptr), 127 found_rows(0), 128 updated_rows(0), 129 fields(field_list), 130 values(value_list), 131 copy_field(nullptr), 132 update_completed(false), 133 trans_safe(true), 134 transactional_tables(false), 135 error_handled(false), 136 update_operations(nullptr) {} need_explain_interceptor()137 bool need_explain_interceptor() const override { return true; } 138 bool prepare(THD *thd, List<Item> &list, SELECT_LEX_UNIT *u) override; 139 bool optimize() override; start_execution(THD *)140 bool start_execution(THD *) override { 141 update_completed = false; 142 return false; 143 } 144 bool send_data(THD *thd, List<Item> &items) override; 145 void send_error(THD *thd, uint errcode, const char *err) override; 146 bool do_updates(THD *thd); 147 bool send_eof(THD *thd) override; 148 void abort_result_set(THD *thd) override; 149 void cleanup(THD *thd) override; 150 151 bool immediate_update(TABLE_LIST *t) const override; 152 }; 153 154 class Sql_cmd_update final : public Sql_cmd_dml { 155 public: Sql_cmd_update(bool multitable_arg,List<Item> * update_values)156 Sql_cmd_update(bool multitable_arg, List<Item> *update_values) 157 : multitable(multitable_arg), update_value_list(update_values) {} 158 sql_command_code()159 enum_sql_command sql_command_code() const override { 160 return multitable ? SQLCOM_UPDATE_MULTI : SQLCOM_UPDATE; 161 } 162 is_single_table_plan()163 bool is_single_table_plan() const override { return !multitable; } 164 165 protected: 166 bool precheck(THD *thd) override; 167 168 bool prepare_inner(THD *thd) override; 169 170 bool execute_inner(THD *thd) override; 171 172 private: 173 bool update_single_table(THD *thd); 174 175 bool multitable; 176 177 bool accept(THD *thd, Select_lex_visitor *visitor) override; 178 179 public: 180 List<Item> *update_value_list; 181 }; 182 183 #endif /* SQL_UPDATE_INCLUDED */ 184