sqlite commands possibly not working in qt

Question

I am making a library management software using Qt and Sqlite3.

constructor:

db = QSqlDatabase :: addDatabase("QSQLITE");
model = new QSqlTableModel(this, db);

db.setDatabaseName(":/lib/libre coupe.db");
db.setHostName("Libre Coupe");

if(db.open())
{
    QSqlQuery query(db);
    if (! query.exec("CREATE TABLE IF NOT EXISTS books (NAME VARCHAR(100) NOT NULL, AUTHOR VARCHAR(100) NOT NULL, UID VARCHAR(100) NOT NULL) "))
    {
        QMessageBox::information(this, "title", "Unable to use Sqlite");
    }

    if(query.lastError().text() != " ")
        QMessageBox::critical(this, "Oops", query.lastError().text());

    model->setTable("books");
    model->select();

    model->setHeaderData(0, Qt::Horizontal, tr("Name") );
    model->setHeaderData(1, Qt::Horizontal, tr("Author") );
    model->setHeaderData(2, Qt::Horizontal, tr("Uid") );
    model->setEditStrategy(QSqlTableModel::OnManualSubmit);

    if(!query.exec("SELECT * FROM books;"))
        QMessageBox::critical(this, "Oops", query.lastError().text());

    int i = 0;

    while(query.next())
    {
        model->setData(model->index(i, 0), query.value(query.record().indexOf("NAME")));
        model->setData(model->index(i, 1), query.value(query.record().indexOf("AUTHOR")));
        model->setData(model->index(i, 2), query.value(query.record().indexOf("UID")));

        ++i;
    }
}
else
    QMessageBox::critical(this, "Oops!", "Could not open the database");\

I faced a problem that the database was not created automatically. So, i created it manually and added it to my resource so that it exists on every computer which uses my application.

I ran my app and went to the directory containing "libre coupe.db". There using the terminal, i found out that no table was created. I see no error message. My other functions like save don't work too while the same commands typed directly into Sqlite using terminal works as expected.

I even used the debugger and found that the program does enter the if condition i.e. the database opens successfully.

I used the following command to check if the table existed:

sqlite3 "libre coupe.db"
.tables

`db.setDatabaseName(":/lib/libre coupe.db");` should be called after `db = QSqlDatabase :: addDatabase("QSQLITE");`, I guess, otherwise you just overwrite it. — vahancho, Apr 16 '18 at 11:00

score 3 · Accepted Answer · answered Apr 16 '18 at 11:03

3

First line:

db.setDatabaseName(":/lib/libre coupe.db");

the starting ":" means you are trying to access an embedded binary resource using Qt's resource system.

However, SQLite databases cannot be stored in the Qt resource system. If your database is instead located at /lib/libre coupe.db, you should remove the colon at the beginning.

answered Apr 16 '18 at 11:03

Sergio Monteleone

2,776
9
21

Actually, at first I dont know why but I was unable to create the database. But now just added wrote libre coupe and the program worked. Thanks a lot – Hemil Apr 16 '18 at 11:07

sqlite commands possibly not working in qt

1 Answers1