sqlconversationmodel.cpp Example File

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 #include "sqlconversationmodel.h"

 #include <QDateTime>
 #include <QDebug>
 #include <QSqlError>
 #include <QSqlRecord>
 #include <QSqlQuery>

 static const char *conversationsTableName = "Conversations";

 static void createTable()
 {
     if (QSqlDatabase::database().tables().contains(conversationsTableName)) {
         // The table already exists; we don't need to do anything.
         return;
     }

     QSqlQuery query;
     if (!query.exec(
         "CREATE TABLE IF NOT EXISTS 'Conversations' ("
         "'author' TEXT NOT NULL,"
         "'recipient' TEXT NOT NULL,"
         "'timestamp' TEXT NOT NULL,"
         "'message' TEXT NOT NULL,"
         "FOREIGN KEY('author') REFERENCES Contacts ( name ),"
         "FOREIGN KEY('recipient') REFERENCES Contacts ( name )"
         ")")) {
         qFatal("Failed to query database: %s", qPrintable(query.lastError().text()));
     }

     query.exec("INSERT INTO Conversations VALUES('Me', 'Ernest Hemingway', '2016-01-07T14:36:06', 'Hello!')");
     query.exec("INSERT INTO Conversations VALUES('Ernest Hemingway', 'Me', '2016-01-07T14:36:16', 'Good afternoon.')");
     query.exec("INSERT INTO Conversations VALUES('Me', 'Albert Einstein', '2016-01-01T11:24:53', 'Hi!')");
     query.exec("INSERT INTO Conversations VALUES('Albert Einstein', 'Me', '2016-01-07T14:36:16', 'Good morning.')");
     query.exec("INSERT INTO Conversations VALUES('Hans Gude', 'Me', '2015-11-20T06:30:02', 'God morgen. Har du fått mitt maleri?')");
     query.exec("INSERT INTO Conversations VALUES('Me', 'Hans Gude', '2015-11-20T08:21:03', 'God morgen, Hans. Ja, det er veldig fint. Tusen takk! "
                "Hvor mange timer har du brukt på den?')");
 }

 SqlConversationModel::SqlConversationModel(QObject *parent) :
     QSqlTableModel(parent)
 {
     createTable();
     setTable(conversationsTableName);
     setSort(2, Qt::DescendingOrder);
     // Ensures that the model is sorted correctly after submitting a new row.
     setEditStrategy(QSqlTableModel::OnManualSubmit);
 }

 QString SqlConversationModel::recipient() const
 {
     return m_recipient;
 }

 void SqlConversationModel::setRecipient(const QString &recipient)
 {
     if (recipient == m_recipient)
         return;

     m_recipient = recipient;

     const QString filterString = QString::fromLatin1(
         "(recipient = '%1' AND author = 'Me') OR (recipient = 'Me' AND author='%1')").arg(m_recipient);
     setFilter(filterString);
     select();

     emit recipientChanged();
 }

 QVariant SqlConversationModel::data(const QModelIndex &index, int role) const
 {
     if (role < Qt::UserRole)
         return QSqlTableModel::data(index, role);

     const QSqlRecord sqlRecord = record(index.row());
     return sqlRecord.value(role - Qt::UserRole);
 }

 QHash<int, QByteArray> SqlConversationModel::roleNames() const
 {
     QHash<int, QByteArray> names;
     names[Qt::UserRole] = "author";
     names[Qt::UserRole + 1] = "recipient";
     names[Qt::UserRole + 2] = "timestamp";
     names[Qt::UserRole + 3] = "message";
     return names;
 }

 void SqlConversationModel::sendMessage(const QString &recipient, const QString &message)
 {
     const QString timestamp = QDateTime::currentDateTime().toString(Qt::ISODate);

     QSqlRecord newRecord = record();
     newRecord.setValue("author", "Me");
     newRecord.setValue("recipient", recipient);
     newRecord.setValue("timestamp", timestamp);
     newRecord.setValue("message", message);
     if (!insertRecord(rowCount(), newRecord)) {
         qWarning() << "Failed to send message:" << lastError().text();
         return;
     }

     submitAll();
 }