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125 lines
4.0 KiB
125 lines
4.0 KiB
5 months ago
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/* Copyright (c) 2015, 2017, 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, version 2.0,
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as published by the Free Software Foundation.
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This program is also distributed with certain software (including
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but not limited to OpenSSL) that is licensed under separate terms,
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as designated in a particular file or component or in included license
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documentation. The authors of MySQL hereby grant you an additional
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permission to link the program and your derivative works with the
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separately licensed software that they have included with MySQL.
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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, version 2.0, 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 02110-1301 USA */
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#ifndef SQL_CMD_DML_INCLUDED
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#define SQL_CMD_DML_INCLUDED
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#include "my_dbug.h"
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#include "sql/sql_cmd.h"
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struct LEX;
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class Query_result;
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class Sql_cmd_dml : public Sql_cmd {
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public:
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/// @return true if data change statement, false if not (SELECT statement)
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virtual bool is_data_change_stmt() const { return true; }
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/**
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Command-specific resolving (doesn't include LEX::prepare())
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@param thd Current THD.
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@returns false on success, true on error
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*/
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virtual bool prepare(THD *thd);
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/**
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Execute this query once.
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@param thd Thread handler
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@returns false on success, true on error
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*/
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virtual bool execute(THD *thd);
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virtual bool is_dml() const { return true; }
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virtual bool is_single_table_plan() const { return false; }
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protected:
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Sql_cmd_dml() : Sql_cmd(), lex(NULL), result(NULL), m_empty_query(false) {}
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/// @return true if query is guaranteed to return no data
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/**
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@todo Also check this for the following cases:
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- Empty source for multi-table UPDATE and DELETE.
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- Check empty query expression for INSERT
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*/
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bool is_empty_query() const {
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DBUG_ASSERT(is_prepared());
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return m_empty_query;
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}
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/// Set statement as returning no data
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void set_empty_query() { m_empty_query = true; }
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/**
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Perform a precheck of table privileges for the specific operation.
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@details
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Check that user has some relevant privileges for all tables involved in
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the statement, e.g. SELECT privileges for tables selected from, INSERT
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privileges for tables inserted into, etc. This function will also populate
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TABLE_LIST::grant with all privileges the user has for each table, which
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is later used during checking of column privileges.
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Note that at preparation time, views are not expanded yet. Privilege
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checking is thus rudimentary and must be complemented with later calls to
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SELECT_LEX::check_view_privileges().
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The reason to call this function at such an early stage is to be able to
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quickly reject statements for which the user obviously has insufficient
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privileges.
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@param thd thread handler
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@returns false if success, true if false
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*/
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virtual bool precheck(THD *thd) = 0;
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/**
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Perform the command-specific parts of DML command preparation,
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to be called from prepare()
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@param thd the current thread
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@returns false if success, true if error
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*/
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virtual bool prepare_inner(THD *thd) = 0;
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/**
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The inner parts of query optimization and execution.
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Single-table DML operations needs to reimplement this.
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@param thd Thread handler
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@returns false on success, true on error
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*/
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virtual bool execute_inner(THD *thd);
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protected:
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LEX *lex; ///< Pointer to LEX for this statement
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Query_result *result; ///< Pointer to object for handling of the result
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bool m_empty_query; ///< True if query will produce no rows
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};
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#endif /* SQL_CMD_DML_INCLUDED */
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