using an isntance of QSqlDatabase for connection defiinition

[anda_skoa]

I can pass it with the sql statement correct ?

Yes.

Will calling addEvent () in the while loop be fine or should it be called once after the while loop is done putting data in struct?

In every loop iteration.
You can basically keep your code, but instead of calling addEvent() on a different model you just call addEvent() of the current object.

I’m still little confused how the virtual functions get called... from my understanding is when the instance variable of my class is created (to pass the model to C++ by setting rootContext item) it makes a call to the constructor and when the constructor gets called the virtual functions get called (trying to clear any confuse I still have with models and virtual functions) ?

When you create an object, the constructor for that class is called.

Once the object is created, calls to virtual functions always end up in the most specific subclass.
E.g. if you overwrite roleNames() a call to roleNames() will end up calling your implementation.

Also I want to call dbConnect and selectQuery() methods from QML (button click)

For what purpose?
I can see a use case of re-running the query on demand, but dbConnect?
dbConnect() is really internal, no? It has to be called before database access happens, so the class itself should know when to call it.

in the header file I declare the function as Q_INVOKABLE now I know I could register the QML type to make the class accessible in QML and import it in the QML to call the function but I think I would have to make the class global object? is there a simpler way to do this ?

That is unnecessary.
Q_INVOKABLE methods and slots are already accessible as functions on an object set as a context property.
Registration of a type is only necessary if instances of that type need to be created from QML or if it has enum definitions where the QML code should be able to use the names.

I have seen an example with Q_INVOKABLE and setting the context property, but I get confused on what engine object/class I need to use to set it.

You don't have to change anything in your code.

Cheers,
_