You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
118 lines
4.2 KiB
118 lines
4.2 KiB
/* This file is part of the KDE project
|
|
Copyright (C) 2005 Jaroslaw Staniek <js@iidea.pl>
|
|
|
|
This library is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU Library General Public
|
|
License as published by the Free Software Foundation; either
|
|
version 2 of the License, or (at your option) any later version.
|
|
|
|
This library 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
|
|
Library General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Library General Public License
|
|
along with this library; see the file COPYING.LIB. If not, write to
|
|
the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
|
|
* Boston, MA 02110-1301, USA.
|
|
*/
|
|
|
|
#ifndef KEXIDB_PREPAREDSTATEMENT_H
|
|
#define KEXIDB_PREPAREDSTATEMENT_H
|
|
|
|
#include <tqvariant.h>
|
|
#include <ksharedptr.h>
|
|
|
|
#include "field.h"
|
|
|
|
namespace KexiDB {
|
|
|
|
class ConnectionInternal;
|
|
class TableSchema;
|
|
class FieldList;
|
|
|
|
/*! @short Prepared database command for optimizing sequences of multiple database actions
|
|
|
|
Currently INSERT and SELECT statements are supported.
|
|
For example, wher using PreparedStatement for INSERTs,
|
|
you can gain about 30% speedup compared to using multiple
|
|
connection.insertRecord(*tabelSchema, dbRowBuffer).
|
|
|
|
To use PreparedStatement, create is using KexiDB::Connection:prepareStatement(),
|
|
providing table schema; set up arguments using operator << ( const TQVariant& value );
|
|
and call execute() when ready. PreparedStatement objects are accessed
|
|
using KDE shared pointers, i.e KexiDB::PreparedStatement::Ptr, so you do not need
|
|
to remember about destroying them. However, when underlying Connection object
|
|
is destroyed, PreparedStatement should not be used.
|
|
|
|
Let's assume tableSchema contains two columns NUMBER integer and TEXT text.
|
|
Following code inserts 10000 records with random numbers and text strings
|
|
obtained elsewhere using getText(i).
|
|
\code
|
|
bool insertMultiple(KexiDB::Connection &conn, KexiDB::TableSchema& tableSchema)
|
|
{
|
|
KexiDB::PreparedStatement::Ptr prepared = conn.prepareStatement(
|
|
KexiDB::PreparedStatement::InsertStatement, tableSchema);
|
|
for (i=0; i<10000; i++) {
|
|
prepared << rand() << getText(i);
|
|
if (!prepared.execute())
|
|
return false;
|
|
prepared.clearArguments();
|
|
}
|
|
return true;
|
|
}
|
|
\endcode
|
|
|
|
If you do not call clearArguments() after every insert, you can insert
|
|
the same value multiple times using execute() what increases efficiency even more.
|
|
|
|
Another use case is inserting large objects (BLOBs or CLOBs).
|
|
Depending on database backend, you can avoid escaping BLOBs.
|
|
See KexiFormView::storeData() for example use.
|
|
*/
|
|
class KEXI_DB_EXPORT PreparedStatement : public TDEShared
|
|
{
|
|
public:
|
|
typedef TDESharedPtr<PreparedStatement> Ptr;
|
|
|
|
//! Defines type of the prepared statement.
|
|
enum StatementType {
|
|
SelectStatement, //!< SELECT statement will be prepared end executed
|
|
InsertStatement //!< INSERT statement will be prepared end executed
|
|
};
|
|
|
|
//! Creates Prepared statement. In your code use KexiDB::Connection:prepareStatement() instead.
|
|
PreparedStatement(StatementType type, ConnectionInternal& conn, FieldList& fields,
|
|
const TQStringList& where = TQStringList());
|
|
|
|
virtual ~PreparedStatement();
|
|
|
|
//! Appends argument \a value to the statement.
|
|
PreparedStatement& operator<< ( const TQVariant& value );
|
|
|
|
//! Clears arguments of the prepared statement. Usually used after execute()
|
|
void clearArguments();
|
|
|
|
/*! Executes the prepared statement. In most cases you will need to clear
|
|
arguments after executing, using clearArguments().
|
|
A number arguments set up for the statement must be the same as a number of fields
|
|
defined in the underlying database table.
|
|
\return false on failure. Detailed error status can be obtained
|
|
from KexiDB::Connection object used to create this statement. */
|
|
virtual bool execute() = 0;
|
|
|
|
protected:
|
|
//! @todo is this portable across backends?
|
|
TQCString generateStatementString();
|
|
|
|
StatementType m_type;
|
|
FieldList *m_fields;
|
|
TQValueList<TQVariant> m_args;
|
|
TQStringList* m_where;
|
|
Field::List* m_whereFields;
|
|
};
|
|
|
|
} //namespace KexiDB
|
|
|
|
#endif
|