Trying to learn. Not declared in this scope error

**poporacer** · 21st September 2010, 05:08

What do I need to do to have the connection and queries in the header file? If put the function in to test if the mxtrainer is there to see if it is the first time the program has run. If it is the first time, create the table. If not use the existing data. Where is the tool for single stepping through the code...I have been using breakpoints to try and find the problems. I got rid of the test and put in QSqlQuery::Last error like this:

Qt Code:

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void createDb()
{
    QSqlQuery query;
    //query.exec("DROP TABLE scooter");
 
    query.exec("CREATE TABLE rider ("
               "id INTEGER PRIMARY KEY AUTOINCREMENT, "
               "name VARCHAR(20) NOT NULL, "
               "weight INTEGER NOT NULL, ");
    query.exec("INSERT INTO rider (name, weight) "
               "VALUES ('Villapoto', 155");
    query.exec("INSERT INTO rider (name, weight) "
               "VALUES ('Carmichael', 165");
    query.exec("INSERT INTO rider (name, weight) "
               "VALUES ('McGrath', 175");
qDebug() << query.lastError();
}
int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    //bool create = !QFile::exists("mxtrainer.dat");
    //if (!createConnection())
        //return 1;
    //if (create)
        createDb();
    MXMainWindow w;
    w.show();
 
    return a.exec();
}

void createDb()
{
    QSqlQuery query;
    //query.exec("DROP TABLE scooter");

    query.exec("CREATE TABLE rider ("
               "id INTEGER PRIMARY KEY AUTOINCREMENT, "
               "name VARCHAR(20) NOT NULL, "
               "weight INTEGER NOT NULL, ");
    query.exec("INSERT INTO rider (name, weight) "
               "VALUES ('Villapoto', 155");
    query.exec("INSERT INTO rider (name, weight) "
               "VALUES ('Carmichael', 165");
    query.exec("INSERT INTO rider (name, weight) "
               "VALUES ('McGrath', 175");
qDebug() << query.lastError();
}
int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    //bool create = !QFile::exists("mxtrainer.dat");
    //if (!createConnection())
        //return 1;
    //if (create)
        createDb();
    MXMainWindow w;
    w.show();

    return a.exec();
}

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I got an error database not open.
Where do I go from here?
PS. I really appreciate all your help!!

**ChrisW67** · 21st September 2010, 05:36

The "Database not open error" is the result of commenting out the createConnection() call, which is opening the database! In your previous attempt the error you would be really interested in was the exec() call after trying to select the rider's names.

The debugging tool you are setting breakpoints in can single-step your program. Look on the Debug menu in Qt Creator when you are stopped at a break point.

I don't know exactly what you mean by "What do I need to do to have the connection and queries in the header file?". You just put the code there and make sure it is included where required. However, it is usually not a good idea to put real implementation code into header files (with the exception of trivial inline methods). The Qt examples do this to simplify the construction of many independent programs that use that example database. Headers are typically expected to contain declarations only, with the implementation (if any) in a matching cpp file.

**poporacer** · 21st September 2010, 05:59

I uncommented out that section and got the error QSqlError(1, "Unable to execute statement", "near "175": syntax error") And stepping in goes through the QT code. Am I missing something?
And when I put in after the Select name query I got: QSqlError(-1, "Unable to fetch row", "No query")

**ChrisW67** · 21st September 2010, 06:19

Your SQL INSERT statements are malformed: missing their closing )

Edit: So is your create table.

**poporacer** · 22nd September 2010, 01:01

Thank you so much...I am starting to figure this out a little bit at a time. I really appreciate your help!
The program works and the combo box gets populated, but in the QSqlError message I get
QSqlError(-1, "", "")
QSqlError(-1, "", "")
I couldn't find any reference to what the -1 or the "","" errors are. Any Ideas?