C++ QSqlQuery::setForwardOnly方法代码示例

long QgsDb2Provider::featureCount() const
{
  // Return the count that we get from the subset.
  if ( !mSqlWhereClause.isEmpty() )
    return mNumberFeatures;

  // On LUW, this could be selected from syscat.tables but I'm not sure if this
  // is actually correct if RUNSTATS hasn't been done.
  // On z/OS, we don't have access to the system catalog.
  // Use count(*) as the easiest approach
  QSqlQuery query = QSqlQuery( mDatabase );
  query.setForwardOnly( true );

  QString sql = "SELECT COUNT(*) FROM %1.%2";
  QString statement = QString( sql ).arg( mSchemaName, mTableName );
  QgsDebugMsg( statement );
  if ( query.exec( statement ) && query.next() )
  {
    QgsDebugMsg( QString( "count: %1" ).arg( query.value( 0 ).toInt() ) );
    return query.value( 0 ).toInt();
  }
  else
  {
    QgsDebugMsg( "Failed" );
    QgsDebugMsg( query.lastError().text() );
    return -1;
  }
}

QStringList QgsMssqlConnection::schemas( const QString &uri, QString *errorMessage )
{
  QgsDataSourceUri dsUri( uri );

// connect to database
  QSqlDatabase db = getDatabase( dsUri.service(), dsUri.host(), dsUri.database(), dsUri.username(), dsUri.password() );

  if ( !openDatabase( db ) )
  {
    if ( errorMessage )
      *errorMessage = db.lastError().text();
    return QStringList();
  }

  const QString sql = QStringLiteral( "select s.name as schema_name from sys.schemas s" );

  QSqlQuery q = QSqlQuery( db );
  q.setForwardOnly( true );
  if ( !q.exec( sql ) )
  {
    if ( errorMessage )
      *errorMessage = q.lastError().text();
    return QStringList();
  }

  QStringList result;

  while ( q.next() )
  {
    const QString schemaName = q.value( 0 ).toString();
    result << schemaName;
  }
  return result;
}

bool QgsDb2Provider::changeGeometryValues( const QgsGeometryMap &geometry_map )
{
  if ( geometry_map.isEmpty() )
    return true;

  if ( mFidColName.isEmpty() )
    return false;

  for ( QgsGeometryMap::const_iterator it = geometry_map.constBegin(); it != geometry_map.constEnd(); ++it )
  {
    QgsFeatureId fid = it.key();
    // skip added features
    if ( FID_IS_NEW( fid ) )
    {
      continue;
    }

    QString statement;
    statement = QString( "UPDATE %1.%2 SET %3 = " )
                .arg( mSchemaName, mTableName, mGeometryColName );

    if ( !mDatabase.isOpen() )
    {
      QString errMsg;
      mDatabase = getDatabase( mConnInfo, errMsg );
      if ( !errMsg.isEmpty() )
      {
        return false;
      }
    }
    QSqlQuery query = QSqlQuery( mDatabase );
    query.setForwardOnly( true );

    statement += QString( "db2gse.%1(CAST (%2 AS BLOB(2M)),%3)" )
                 .arg( mGeometryColType,
                       QString( "?" ),
                       QString::number( mSRId ) );

    // set attribute filter
    statement += QString( " WHERE %1=%2" ).arg( mFidColName, FID_TO_STRING( fid ) );
    QgsDebugMsg( statement );
    if ( !query.prepare( statement ) )
    {
      QgsDebugMsg( query.lastError().text() );
      return false;
    }

    // add geometry param
    QByteArray bytea = QByteArray(( char* )it->asWkb(), ( int ) it->wkbSize() );
    query.addBindValue( bytea, QSql::In | QSql::Binary );

    if ( !query.exec() )
    {
      QgsDebugMsg( query.lastError().text() );
      return false;
    }
  }

  return true;
}

bool QgsMssqlConnection::createSchema( const QString &uri, const QString &schemaName, QString *errorMessage )
{
  QgsDataSourceUri dsUri( uri );

  // connect to database
  QSqlDatabase db = getDatabase( dsUri.service(), dsUri.host(), dsUri.database(), dsUri.username(), dsUri.password() );

  if ( !openDatabase( db ) )
  {
    if ( errorMessage )
      *errorMessage = db.lastError().text();
    return false;
  }

  QSqlQuery q = QSqlQuery( db );
  q.setForwardOnly( true );
  const QString sql = QStringLiteral( "CREATE SCHEMA [%1]" ).arg( schemaName );
  if ( !q.exec( sql ) )
  {
    if ( errorMessage )
      *errorMessage = q.lastError().text();
    return false;
  }

  return true;
}

bool QgsMssqlConnection::truncateTable( const QString &uri, QString *errorMessage )
{
  QgsDataSourceUri dsUri( uri );

  // connect to database
  QSqlDatabase db = getDatabase( dsUri.service(), dsUri.host(), dsUri.database(), dsUri.username(), dsUri.password() );
  const QString schema = dsUri.schema();
  const QString table = dsUri.table();

  if ( !openDatabase( db ) )
  {
    if ( errorMessage )
      *errorMessage = db.lastError().text();
    return false;
  }

  QSqlQuery q = QSqlQuery( db );
  q.setForwardOnly( true );
  const QString sql = QStringLiteral( "TRUNCATE TABLE [%1].[%2]" ).arg( schema, table );
  if ( !q.exec( sql ) )
  {
    if ( errorMessage )
      *errorMessage = q.lastError().text();
    return false;
  }

  return true;
}

bool QgsMssqlConnection::dropTable( const QString &uri, QString *errorMessage )
{
  QgsDataSourceUri dsUri( uri );

  // connect to database
  QSqlDatabase db = getDatabase( dsUri.service(), dsUri.host(), dsUri.database(), dsUri.username(), dsUri.password() );
  const QString schema = dsUri.schema();
  const QString table = dsUri.table();

  if ( !openDatabase( db ) )
  {
    if ( errorMessage )
      *errorMessage = db.lastError().text();
    return false;
  }

  QSqlQuery q = QSqlQuery( db );
  q.setForwardOnly( true );
  const QString sql = QString( "IF EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'[%1].[%2]') AND type in (N'U')) DROP TABLE [%1].[%2]\n"
                               "DELETE FROM geometry_columns WHERE f_table_schema = '%1' AND f_table_name = '%2'" )
                      .arg( schema,
                            table );
  if ( !q.exec( sql ) )
  {
    if ( errorMessage )
      *errorMessage = q.lastError().text();
    return false;
  }

  return true;
}

QStringList SqliteDriver::tables(const QString &typeName) const
{
  QStringList res;
  if (!isOpen() || !dataBase_)
    return res;
  int type = typeName.toInt();

  QSqlQuery q = createQuery();
  q.setForwardOnly(TRUE);
#if (QT_VERSION-0 >= 0x030000)
  if ((type & (int)QSql::Tables) && (type & (int)QSql::Views))
    q.exec("SELECT name FROM sqlite_master WHERE type='table' OR type='view'");
  else if (typeName.isEmpty() || (type & (int)QSql::Tables))
    q.exec("SELECT name FROM sqlite_master WHERE type='table'");
  else if (type & (int)QSql::Views)
    q.exec("SELECT name FROM sqlite_master WHERE type='view'");
#else
  q.exec("SELECT name FROM sqlite_master WHERE type='table' OR type='view'");
#endif


  if (q.isActive()) {
    while (q.next())
      res.append(q.value(0).toString());
  }

#if (QT_VERSION-0 >= 0x030000)
  if (type & (int)QSql::SystemTables) {
    // there are no internal tables beside this one:
    res.append("sqlite_master");
  }
#endif

  return res;
}

// This should go into Qt 4.8 once we start using it for Qt Creator
QMap<QString, QUrl> HelpManager::linksForKeyword(const QString &key)
{
    QMap<QString, QUrl> links;
    if (d->m_needsSetup)
        return links;

    const QLatin1String sqlite("QSQLITE");
    const QLatin1String name("HelpManager::linksForKeyword");

    DbCleaner cleaner(name);
    QSqlDatabase db = QSqlDatabase::addDatabase(sqlite, name);
    if (db.driver() && db.driver()->lastError().type() == QSqlError::NoError) {
        const QStringList &registeredDocs = d->m_helpEngine->registeredDocumentations();
        foreach (const QString &nameSpace, registeredDocs) {
            db.setDatabaseName(d->m_helpEngine->documentationFileName(nameSpace));
            if (db.open()) {
                QSqlQuery query = QSqlQuery(db);
                query.setForwardOnly(true);
                query.exec(QString::fromLatin1(linksForKeyQuery).arg(key));
                while (query.next()) {
                    QString title = query.value(0).toString();
                    if (title.isEmpty()) // generate a title + corresponding path
                        title = key + QLatin1String(" : ") + query.value(3).toString();
                    links.insertMulti(title, buildQUrl(query.value(1).toString(),
                                                       query.value(2).toString(), query.value(3).toString(),
                                                       query.value(4).toString()));
                }
            }
        }
    }

void QgsMssqlNewConnection::listDatabases()
{
  testConnection( "master" );
  listDatabase->clear();
  QString queryStr = "SELECT name FROM master..sysdatabases WHERE name NOT IN ('master', 'tempdb', 'model', 'msdb')";

  QSqlDatabase db = QgsMssqlProvider::GetDatabase( txtService->text().trimmed(),
                    txtHost->text().trimmed(),
                    "master",
                    txtUsername->text().trimmed(),
                    txtPassword->text().trimmed() );
  if ( db.open() )
  {
    QSqlQuery query = QSqlQuery( db );
    query.setForwardOnly( true );
    query.exec( queryStr );

    if ( !txtService->text().isEmpty() )
    {
      listDatabase->addItem( "(from service)" );
    }

    if ( query.isActive() )
    {
      while ( query.next() )
      {
        QString name = query.value( 0 ).toString();
        listDatabase->addItem( name );
      }
      listDatabase->setCurrentRow( 0 );
    }
    db.close();
  }
}

QSqlIndex SqliteDriver::primaryIndex2(const QString &tblname) const
{
  QSqlRecordInfo rec(recordInfo(tblname));     // expensive :(

  if (!isOpen() || !dataBase_)
    return QSqlIndex();

  QSqlQuery q = createQuery();
  q.setForwardOnly(TRUE);
  // finrst find a UNIQUE INDEX
  q.exec("PRAGMA index_list('" + tblname + "');");
  QString indexname;
  while (q.next()) {
    if (q.value(2).toInt() == 1) {
      indexname = q.value(1).toString();
      break;
    }
  }
  if (indexname.isEmpty())
    return QSqlIndex();

  q.exec("PRAGMA index_info('" + indexname + "');");

  QSqlIndex index(tblname, indexname);
  while (q.next()) {
    QString name = q.value(2).toString();
    QSqlVariant::Type type = QSqlVariant::Invalid;
    if (rec.contains(name))
      type = rec.find(name).type();
    index.append(QSqlField(name, type));
  }
  return index;
}

/*!
	Loads Custom tags under the \a key serial from the persistent storage
*/
void cCustomTags::load( SERIAL key )
{
	if ( tags_ )
		tags_->clear();

	QSqlQuery result;
	result.setForwardOnly( true );
	result.prepare( "SELECT name,type,value FROM tags WHERE serial = ?" );
	result.addBindValue( key );
	result.exec();

	while ( result.next() )
	{
		QString name = result.value( 0 ).toString();
		QString type = result.value( 1 ).toString();
		QString value = result.value( 2 ).toString();

		if ( !tags_ )
			tags_ = new QMap<QString, cVariant>;

		if ( type == "String" )
			tags_->insert( name, cVariant( value ) );
		else if ( type == "Int" )
			tags_->insert( name, cVariant( value.toInt() ) );
		else if ( type == "Double" )
			tags_->insert( name, cVariant( value.toDouble() ) );
	}

	changed = false;
}

void CTaskType::slotFindTask(const QString &text)
{
    QList<QVariant> list;
    QSqlQuery       stored;

#ifndef QT_NO_CURSOR
        QApplication::setOverrideCursor(QCursor(QPixmap("data/picture/additionally/wait.png")));
#endif

        list.append((int)actualRecords);
        list.append(text);
        stored.setForwardOnly(true);
        stored = execStored(currentDatabase(), "FindTaskType", storageHashTable(list));

        bool empty(false);
        while (stored.next()){
            empty = true;
        }

        stored = execStored(currentDatabase(), "FindTaskType", storageHashTable(list));

        if (empty) {
            fillTaskModel(stored);
        }

#ifndef QT_NO_CURSOR
        QApplication::restoreOverrideCursor();
#endif
        stored.finish();
}

void SecurityManager::deleteUser(const QString &name)
{
    if (isSql()) {
        QSqlQuery q;
        q.setForwardOnly(true);
        q.prepare("delete from trainers where name=:name");
        q.bindValue(":name", name.toLower());
        q.exec();
        return;
    }

    Member m = member(name);

    assert (m.name.length() > 0);

    m.name[0] = ':'; //invalid character, will not get loaded when reloading database
    memberFile.seek(m.filepos);
    members[name].write(&memberFile);
    memberFile.flush();

    playersByIp.remove(m.ip, name);
    authed.remove(name);
    members.erase(name);
    bannedMembers.remove(name.toLower());

    if (bannedIPs.contains(m.ip) && !playersByIp.contains(m.ip)) {
        bannedIPs.remove(m.ip);
    }
}

QSqlError QrSqlHelper::call_query(QrSqlQuery &query, QSqlDatabase *database /* = nullptr */)
{
    QSqlError dbError;
    if (dbError.isValid()) {
        return dbError;
    }

    QSqlQuery qQuery = QSqlQuery(*database);
    qQuery.setForwardOnly(true);

    QTime timeQuery;
    timeQuery.start ();
    qQuery.prepare (query.query ());
    query.resolve(qQuery);

    if (! qQuery.exec ()) {
        qDebug() << "query exec fail, " << query.query ();
        return qQuery.lastError ();
    }
    query.resolveOutput(qQuery, true);

    int ms = timeQuery.elapsed ();
    //  set is print sql query statement or not
    if (QrSqlConfig::getInstance ()->getTraceSqlQuery ()) {
        qDebug() << "custom sql query "<< "(" <<ms << " ms) : " << query.query ()
                 << " by " << database;
    }

    return QSqlError();
}

QStringList SecurityManager::membersForIp(const QString &ip)
{
    if (isSql()) {
        QSqlQuery q;
        q.setForwardOnly(true);

        if (SQLCreator::databaseType == SQLCreator::SQLite) {
            /* On SQLite, there's some bug with the qt driver probably,
                but here it oftens return nothing if i use '=' instead of 'like', so... */
            q.prepare("select name from trainers where ip like ?");
        } else {
            q.prepare("select name from trainers where ip=?");
        }
        q.addBindValue(ip);
        q.exec();

        QStringList ret;

        while (q.next()) {
            ret.push_back(q.value(0).toString());
        }

        return ret;
    }
    return playersByIp.values(ip);
}