Qt 5.9 | Qt Quick Controls 2 | Qt Quick Controls 2 - Chat Tutorial | sqlconversationmodel.cpp Example File

Qt 5.9.2 Reference Documentation

# sqlconversationmodel.cpp Example File

chattutorial/chapter4-models/sqlconversationmodel.cpp

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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();
      }