Transaction Class Reference

QSqlDatabase transaction wrapper. More...

#include <EasyQtSql_Transaction.h>

Inheritance diagram for Transaction:

Public Member Functions
	Transaction (const QSqlDatabase &db=QSqlDatabase())
	Transaction (Transaction &&other)
Transaction &	operator= (Transaction &&other)
	~Transaction ()
bool	commit ()
	Commits transaction. More...
bool	rollback ()
	Rolls back transaction. More...
bool	started () const
	Returns true if the transaction has been started successfully. Otherwise it returns false. More...
bool	commited () const
	Returns true if the transaction has been commited successfully. Otherwise it returns false. More...
Public Member Functions inherited from Database
	Database (const QSqlDatabase &db=QSqlDatabase())
	Database (Database &&other)
Database &	operator= (Database &&other)
QSqlError	lastError () const
	Returns information about the last error that occurred on the underlying database. More...
NonQueryResult	execNonQuery (const QString &sql) const
	Executes non-query SQL statement (DELETE, INSERT, UPDATE, CREATE, ALTER, etc.) More...
QueryResult	execQuery (const QString &sql) const
	Executes SELECT query. More...
InsertQuery	insertInto (const QString &table) const
	Creates INSERT query wrapper. More...
DeleteQuery	deleteFrom (const QString &table) const
	Creates DELETE query wrapper. More...
UpdateQuery	update (const QString &table) const
	Creates UPDATE query wrapper. More...
PreparedQuery	prepare (const QString &sql, bool forwardOnly=true) const
	Prepares SQL statement. More...
QSqlDatabase &	qSqlDatabase ()
	Returns a reference to the wrapped QSqlDatabase object. More...
template<typename Func >
int	each (const QString &query, Func &&f) const
	Executes query and applies function f to each result row. More...
template<typename Func >
int	first (const QString &query, Func &&f) const
	Executes query and applies function f to the first result row. More...
template<typename Func >
int	range (const QString &query, int start, int count, Func &&f) const
	Executes query and applies function f to count result rows starting from index start. More...
template<typename Func >
int	top (const QString &query, int topCount, Func &&f) const
	Executes query and applies function f to topCount result rows. More...
template<typename T >
T	scalar (const QString &query) const
	Executes query and returns scalar value converted to T. More...
QVariant	scalar (const QString &query) const
	Executes query and returns scalar value. More...

Additional Inherited Members
Protected Attributes inherited from Database
QSqlDatabase	m_db

Detailed Description

QSqlDatabase transaction wrapper.

Features:

• Automatic rollback of non-expclicitely commited transactions
• Helper methods: Transaction::execNonQuery, Transaction::execQuery, Transaction::insertInto, Transaction::deleteFrom, Transaction::update, Transaction::prepare.

void test()
{
   QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE");
   db.setDatabaseName(":memory:");
   db.open();

   try
   {
      Transaction t(db);

      t.execNonQuery("CREATE TABLE table (a int, b int, c int, d text)");

      t.insertInto("table (a, b, c, d)")
         .values(1, 2, 3, "row1")
         .values(4, 5, 6, "row2")
         .values(7, 8, 9, "row3")
         .exec();

      PreparedQuery query = t.prepare("SELECT a, b, c, d FROM table");

      QueryResult res = query.exec();
      while (res.next())
      {
         QVariantMap map = res.toMap();
         qDebug() << map;
      }

      t.update("table")
         .set("a", 111)
         .set("b", 222)
         .where("c = ? OR c = ?", 3, 6);

      res = query.exec();
      while (res.next())
      {
         QVariantMap map = res.toMap();
         qDebug() << map;
      }

      t.commit(); //the transaction will be rolled back on exit from the scope (when calling the destructor) if you do not explicitly commit

   catch (const DBException &e)
   {
      //you can handle all the errors at one point
      //the transaction will be automatically rolled back on exception

      qDebug() << e.lastError << e.lastQuery;
   }
}

Constructor & Destructor Documentation

Transaction() [1/2]

Transaction::Transaction ( const QSqlDatabase &  db = QSqlDatabase() )

inlineexplicit

Transaction() [2/2]

Transaction::Transaction ( Transaction &&  other )

inline

~Transaction()

Transaction::~Transaction ( )

inline

Member Function Documentation

commit()

bool Transaction::commit ( )

inline

Commits transaction.

The transaction will be rolled back on calling the destructor if not explicitly commited

Exceptions

DBException

commited()

bool Transaction::commited ( ) const

inline

Returns true if the transaction has been commited successfully. Otherwise it returns false.

operator=()

Transaction& Transaction::operator= ( Transaction &&  other )

inline

rollback()

bool Transaction::rollback ( )

inline

Rolls back transaction.

started()

bool Transaction::started ( ) const

inline

Returns true if the transaction has been started successfully. Otherwise it returns false.

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The documentation for this class was generated from the following file:

• EasyQtSql/EasyQtSql_Transaction.h