README0100664000175300003300000000034510566332112010725 0ustar jillljeditThis is a sample application demonstrating asynchronous database access with Qt. To compile: qmake make (or nmake) By default, this sample app will use sqlite to create a local database. See db.h to change this behavior. asynchdb.pro0100664000175300003300000000026510566173053012372 0ustar jillljeditTEMPLATE = app TARGET = asynchdb CONFIG += qt thread QT = core gui sql FORMS = win.ui HEADERS += querythread.h win_impl.h SOURCES += main.cpp querythread.cpp win_impl.cpp db.h0100664000175300003300000000041310566334630010606 0ustar jillljedit#ifndef DB_H #define DB_H // Configure runtime parameters here #define DATABASE_USER "magdalena" #define DATABASE_PASS "deedee" #define DATABASE_NAME "asynchdbtest.db" #define DATABASE_HOST "" #define DATABASE_DRIVER "QSQLITE" #define SAMPLE_RECORDS 100000 #endif main.cpp0100664000175300003300000000043210566172340011477 0ustar jillljedit/* Asynchronous Database Access With Qt Example program. See db.h to change database connection parameters. */ #include #include "win_impl.h" int main( int argc, char **argv ) { QApplication app( argc, argv ); Win win; win.show(); return app.exec(); } querythread.cpp0100664000175300003300000000577410566334564013136 0ustar jillljedit#include "querythread.h" #include "db.h" #include #include #include #include #include #include // The class that does all the work with the database. This class will // be instantiated in the thread object's run() method. class Worker : public QObject { Q_OBJECT public: Worker( QObject* parent = 0); ~Worker(); public slots: void slotExecute( const QString& query ); signals: void results( const QList& records ); private: QSqlDatabase m_database; }; // Worker::Worker( QObject* parent ) : QObject( parent ) { // thread-specific connection, see db.h m_database = QSqlDatabase::addDatabase( DATABASE_DRIVER, "WorkerDatabase" ); // named connection m_database.setDatabaseName( DATABASE_NAME ); m_database.setHostName( DATABASE_HOST ); m_database.setUserName( DATABASE_USER ); m_database.setPassword( DATABASE_PASS ); if ( !m_database.open() ) { qWarning() << "Unable to connect to database, giving up:" << m_database.lastError().text(); return; } // initialize db if ( !m_database.tables().contains( "item" ) ) { // some data m_database.exec( "create table item(id int, name varchar);" ); m_database.transaction(); QSqlQuery query(m_database); query.prepare("INSERT INTO item (id, name) " "VALUES (?,?)"); for ( int i = 0; i < SAMPLE_RECORDS; ++i ) { query.addBindValue(i); query.addBindValue(QString::number(i)); query.exec(); } m_database.commit(); } } Worker::~Worker() { } void Worker::slotExecute( const QString& query ) { QList recs; QSqlQuery sql( query, m_database ); while ( sql.next() ) { recs.push_back( sql.record() ); } emit results( recs ); } //// QueryThread::QueryThread(QObject *parent) : QThread(parent) { } QueryThread::~QueryThread() { delete m_worker; } void QueryThread::execute( const QString& query ) { emit executefwd( query ); // forwards to the worker } void QueryThread::run() { emit ready(false); emit progress( "QueryThread starting, one moment please..." ); // Create worker object within the context of the new thread m_worker = new Worker(); connect( this, SIGNAL( executefwd( const QString& ) ), m_worker, SLOT( slotExecute( const QString& ) ) ); // Critical: register new type so that this signal can be // dispatched across thread boundaries by Qt using the event // system qRegisterMetaType< QList >( "QList" ); // forward final signal connect( m_worker, SIGNAL( results( const QList& ) ), this, SIGNAL( results( const QList& ) ) ); emit progress( "Press 'Go' to run a query." ); emit ready(true); exec(); // our event loop } #include "querythread.moc" querythread.h0100664000175300003300000000120510566172500012552 0ustar jillljedit#ifndef RENDERTHREAD_H #define RENDERTHREAD_H #include #include #include #include #include #include #include class Worker; // forw decl class QueryThread : public QThread { Q_OBJECT public: QueryThread(QObject *parent = 0); ~QueryThread(); void execute( const QString& query ); signals: void progress( const QString& msg ); void ready(bool); void results( const QList& records ); protected: void run(); signals: void executefwd( const QString& query ); private: Worker* m_worker; }; #endif win.ui0100664000175300003300000000443310566110472011206 0ustar jillljedit win 0 0 383 351 Asynchronous Database Access With Qt 9 6 0 6 &Go Qt::Horizontal 271 20 false Qt::NoTextInteraction 0 6 Qt::Horizontal 261 20 &Close true win_impl.cpp0100664000175300003300000000274410566334203012377 0ustar jillljedit#include "win_impl.h" #include "querythread.h" #include Win::Win( QWidget* parent ) : QWidget(parent) { m_querythread = new QueryThread(); setupUi( this ); // Buttons connect( goButton, SIGNAL( clicked() ), this, SLOT( slotGo() ) ); connect( closeButton, SIGNAL( clicked() ), this, SLOT( close() ) ); // Worker thread connect( m_querythread, SIGNAL( progress(const QString&) ), textBrowser, SLOT( append(const QString&) ) ); connect( m_querythread, SIGNAL( ready(bool) ), goButton, SLOT( setEnabled(bool) ) ); connect( m_querythread, SIGNAL( results( const QList& ) ), this, SLOT( slotResults( const QList& ) ) ); // Launch worker thread m_querythread->start(); } Win::~Win() { m_querythread->quit(); m_querythread->wait(); delete m_querythread; } void Win::slotGo() { textBrowser->append( "Running queries, please wait..." ); dispatch( "select avg(id) from item;" ); dispatch( "select name from item;" ); dispatch( "select min(id) from item;" ); dispatch( "select max(id) from item;" ); dispatch( "select distinct(id) from item;" ); } void Win::dispatch( const QString& query ) { textBrowser->append( "Executing:" + query ); m_querythread->execute( query ); } void Win::slotResults( const QList& records ) { textBrowser->append( QString("Result count:%1").arg( records.count() ) ); } win_impl.h0100664000175300003300000000077110566172347012053 0ustar jillljedit#ifndef WIN_IMPL_H #define WIN_IMPL_H #include #include #include #include "ui_win.h" class QueryThread; class Win : public QWidget, protected Ui::win { Q_OBJECT public: Win( QWidget* parent = 0 ); ~Win(); signals: void exec( const QString& ); private slots: void slotGo(); void slotResults( const QList& records ); private: QueryThread* m_querythread; void dispatch( const QString& query ); }; #endif