bookwindow.cpp Example File

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#include "bookwindow.h"
#include "bookdelegate.h"
#include "initdb.h"
#include <QtSql>
BookWindow::BookWindow()
{
    ui.setupUi(this);
    if (!QSqlDatabase::drivers().contains("QSQLITE"))
        QMessageBox::critical(this, "Unable to load database", "This demo needs the SQLITE driver");
    // initialize the database
    QSqlError err = initDb();
    if (err.type() != QSqlError::NoError) {
        showError(err);
        return;
    }
    // Create the data model
    model = new QSqlRelationalTableModel(ui.bookTable);
    model->setEditStrategy(QSqlTableModel::OnManualSubmit);
    model->setTable("books");
    // Remember the indexes of the columns
    authorIdx = model->fieldIndex("author");
    genreIdx = model->fieldIndex("genre");
    // Set the relations to the other database tables
    model->setRelation(authorIdx, QSqlRelation("authors", "id", "name"));
    model->setRelation(genreIdx, QSqlRelation("genres", "id", "name"));
    // Set the localized header captions
    model->setHeaderData(authorIdx, Qt::Horizontal, tr("Author Name"));
    model->setHeaderData(genreIdx, Qt::Horizontal, tr("Genre"));
    model->setHeaderData(model->fieldIndex("title"), Qt::Horizontal, tr("Title"));
    model->setHeaderData(model->fieldIndex("year"), Qt::Horizontal, tr("Year"));
    model->setHeaderData(model->fieldIndex("rating"), Qt::Horizontal, tr("Rating"));
    // Populate the model
    if (!model->select()) {
        showError(model->lastError());
        return;
    }
    // Set the model and hide the ID column
    ui.bookTable->setModel(model);
    ui.bookTable->setItemDelegate(new BookDelegate(ui.bookTable));
    ui.bookTable->setColumnHidden(model->fieldIndex("id"), true);
    ui.bookTable->setSelectionMode(QAbstractItemView::SingleSelection);
    // Initialize the Author combo box
    ui.authorEdit->setModel(model->relationModel(authorIdx));
    ui.authorEdit->setModelColumn(model->relationModel(authorIdx)->fieldIndex("name"));
    ui.genreEdit->setModel(model->relationModel(genreIdx));
    ui.genreEdit->setModelColumn(model->relationModel(genreIdx)->fieldIndex("name"));
    QDataWidgetMapper *mapper = new QDataWidgetMapper(this);
    mapper->setModel(model);
    mapper->setItemDelegate(new BookDelegate(this));
    mapper->addMapping(ui.titleEdit, model->fieldIndex("title"));
    mapper->addMapping(ui.yearEdit, model->fieldIndex("year"));
    mapper->addMapping(ui.authorEdit, authorIdx);
    mapper->addMapping(ui.genreEdit, genreIdx);
    mapper->addMapping(ui.ratingEdit, model->fieldIndex("rating"));
    connect(ui.bookTable->selectionModel(), SIGNAL(currentRowChanged(QModelIndex,QModelIndex)),
            mapper, SLOT(setCurrentModelIndex(QModelIndex)));
    ui.bookTable->setCurrentIndex(model->index(0, 0));
}
void BookWindow::showError(const QSqlError &err)
{
    QMessageBox::critical(this, "Unable to initialize Database",
                "Error initializing database: " + err.text());
}