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#ifndef SQL_TRUNCATE_INCLUDED
#define SQL_TRUNCATE_INCLUDED
/* Copyright (c) 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 02110-1301 USA */
class THD;
struct TABLE_LIST;
/**
Truncate_statement represents the TRUNCATE statement.
*/
class Truncate_statement : public Sql_statement
{
private:
/* Set if a lock must be downgraded after truncate is done. */
MDL_ticket *m_ticket_downgrade;
public:
/**
Constructor, used to represent a ALTER TABLE statement.
@param lex the LEX structure for this statement.
*/
Truncate_statement(LEX *lex)
: Sql_statement(lex)
{}
virtual ~Truncate_statement()
{}
/**
Execute a TRUNCATE statement at runtime.
@param thd the current thread.
@return false on success.
*/
bool execute(THD *thd);
protected:
/** Handle locking a base table for truncate. */
bool lock_table(THD *, TABLE_LIST *, bool *);
/** Truncate table via the handler method. */
int handler_truncate(THD *, TABLE_LIST *, bool);
/**
Optimized delete of all rows by doing a full regenerate of the table.
Depending on the storage engine, it can be accomplished through a
drop and recreate or via the handler truncate method.
*/
bool truncate_table(THD *, TABLE_LIST *);
};
#endif
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