CODEWITHSUNDEEP
c++qtms-accessodbc
Liviu
Liviu

Reputation: 1917

Detect that the Microsoft Access driver are installed

I can connect to an old Access database with the following code:

bool LoadDb(const QString& file_path, QSqlDatabase& db_out, QSqlError& err)
{
    QSqlDatabase db = QSqlDatabase::addDatabase("QODBC");

    static const auto DRIVER_NAME = R"({Microsoft Access Driver (*.mdb, *.accdb)})";
    const auto connection_string = QString(R"(Driver=%1;DSN='';DBQ=%2)").arg(DRIVER_NAME, file_path);
    db.setDatabaseName(connection_string);
    if (!db.open())
    {
        err = db.lastError();
        return false;
    }

    db_out = std::move(db);

    return true;
}

But I would like to previously test that the driver ("Microsoft Access Database Engine") is installed so could I show a meaningful message for the user.

The following connection string does not work:

const auto connection_string = QString(R"(Driver=%1)").arg(DRIVER_NAME);

The error means nothing ... and it is in French:

[Microsoft][Pilote ODBC Microsoft Access]Erreur générale Impossible d'ouvrir la clé de Registre « Temporary (volatile) Ace DSN for process 0xa74 Thread 0xce4 DBC 0xb5518368                                                              Jet ». QODBC3: Unable to connect

Any idea? Preferably portable code.

Upvotes: 0

Views: 595

Answers (1)

erg
erg

Reputation: 1652

If you can access the SQLSTATE you check for an SQLState of IM002. I think IM002 is always returned if the driver cannot be found / loaded, while if for example the database file cannot be found because the path is wrong, you would get a HY000 SQLSTATE:

For an invalid driver string I get:

SQLSTATE IM002; Native Error: 0; [Microsoft][ODBC Driver Manager] Data source name not found and no default driver specified

For an invalid path I get:

SQLSTATE HY000; Native Error: -1044; [Microsoft][ODBC Microsoft Access Driver] Not a valid file name.

See here for more details about the values returned: https://learn.microsoft.com/en-us/sql/odbc/reference/syntax/sqlconnect-function

Upvotes: 1

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