Multiple QSqlTableModels edited together in one transaction

michmu

I have a window in a Qt application using PostgreSQL 9.3 database. The window is a form used do display, edit and insert new data. t looks like that:

!http://i.stack.imgur.com/4Yu62.jpg(data edit form)!

I have data from 3 sql tables in that view. the tables are related with foreign keys:

contractors (main table) - mapped to "personal data" section
contacts (has foreign key to contractors.ID)
addresses (has foreign key to contractors.ID)

So - in my window's class I have 3 main models (+ 2 proxy models to transpose tables in "personal data" an "address data" sections). I use QSqlTableModel for theese sesctions, and a QSqlRelationalTableModel for contactData section. when opening that window "normally" (to view some contractor), i simply pass contractor's ID to the constructor and store it in proper variable. Also, I call the QSqlTableModel::setFilter(const QString & filter) method for each of the models, and set the proper filtering. When opening that window in "add new" mode i simply pass a "-1" or "0" value to the ID variable, so no data gets loaded to the model. All 3 models have QSqlTableModel::OnManualSubmit editStrategy. When saving the data (triggered by clicking a proper button), I start a transaction. And then I submit models one-by-one. personalData model gets submitted first, as I need to obtain it's PK after insert (to set in the FK fields in other models). When submitting of the model fails, I show a messageBox with the QSqlError content, rollback the transaction and return from the method. When I have an error on the first model being processed - no problem, as nothing was inserted. But when the first model is saved, but the second or third fails - there is a little problem. So I rollback the transacion as before, and return from the function. But after correcting the data and submitting it again - the first model is not trying to submit - as it doesn't know that there was a rollback, and the data needs to be inserted again. What would be a good way to notice such a model, that it needs to be submited once again? At the moment I ended up with something like that:

@void kontrahenciSubWin::on_btnContractorAdd_clicked() {
//QStringList errorList; // when error occurs in one model - whole transacion gets broken, so no need for a list
QString error;
QSqlDatabase db = QSqlDatabase::database();

//backup the data - in case something fails and we have to rollback the transaction
QSqlRecord personalDataModelrec = personalDataModel->record(0); // always one row. will get erased by SubmitAll, as no filter is set, because I don't have its ID.

QList<QSqlRecord> contactDataModelRecList;
for (int i = 0 ; i< contactDataModel->rowCount(); i++) {
    contactDataModelRecList.append( contactDataModel->record(i) );
}

QList<QSqlRecord> addressDataModelRecList;
for (int i = 0 ; i< addressDataModel->rowCount(); i++) {
    addressDataModelRecList.append( addressDataModel->record(i) );
}

db.transaction();
if ( personalDataModel->isDirty() && error.isEmpty() ) {
    if (!personalDataModel->submitAll()) //submitAll calls select() on the model, which destroys the data as the filter is invalid ("where ID = -1")
        //errorList.append( personalDataModel->lastError().databaseText() );
        error = personalDataModel->lastError().databaseText(); 
    else {
        kontrahentid = personalDataModel->query().lastInsertId().toInt(); //only here can I fetch ID
        setFilter(ALL); //and pass it to the models
    }
}

if ( contactDataModel->isDirty() && error.isEmpty() ) 
    if (!contactDataModel->submitAll()) //slot on_contactDataModel_beforeInsert() sets FK field
        //errorList.append( contactDataModel->lastError().databaseText() );
        error = contactDataModel->lastError().databaseText();

if ( addressDataModel->isDirty() && error.isEmpty() )
    if (!addressDataModel->submitAll()) //slot on_addressDataModel_beforeInsert() sets FK field
        //errorList.append( addressDataModel->lastError().databaseText() );
        error = addressDataModel->lastError().databaseText();

//if (!errorList.isEmpty()) {
//  QMessageBox::critical(this, tr("Data was not saved!"), tr("The following errors occured:") + " \n" + errorList.join("\n"));
if (!error.isEmpty()) {
    QMessageBox::critical(this, tr("Data was not saved!"), tr("The following errors occured:") + " \n" + error);

    db.rollback();
    personalDataModel->clear();
    contactDataModel->clear();
    addressDataModel->clear();
    initModel(ALL); //re-init models: set table and so on.

    //re-add data to the models - backup comes handy
    personalDataModel->insertRecord(-1, personalDataModelrec);

    for (QList<QSqlRecord>::iterator it = contactDataModelRecList.begin(); it != contactDataModelRecList.end(); it++) {
        contactDataModel->insertRecord(-1, *it);
    }

    for (QList<QSqlRecord>::iterator it = addressDataModelRecList.begin(); it != addressDataModelRecList.end(); it++) {
        addressDataModel->insertRecord(-1, *it);
    }

    return;
}
db.commit();
isInEditMode = false;
handleGUIOnEditModeChange();

}@

Does anyone have a better idea? I doubt if it's possible to ommit backing-up the records before trying to insert them. But maybe there is a better way to "readd" them to the model? I tried to use "setRecord", and "remoweRows" & "insertRecord" combo, but no luck. Resetting the whole model seems easiest (I only need to re-init it, as it loses table, filter, sorting and everything else when cleared)
I wish Qt had a feature, that would allow to somehow "bind" a transaction object to the model (or some models to a transaction), and that the model could react itself when the transaction is rollback'ed