Question regarding creating general/table agnostic methods

[piperun]

I'm trying to write my own connectOrCreate() function that exists in Prisma, the issue I'm running into is that there doesn't seem to be a direct way of creating a general/generic/table agnostic solution from what I've scoured the documentation, so I'm wondering if there is one and I happen to miss it or am I out of luck?

This is somewhat what I want to be able to accomplish:

// database.dart
class AppDatabase extends _$AppDatabase {
  Future<void> connectOrCreate<T extends Table, D extends DataClass>(Insertable<D>  id, Insertable<D>  item) {
  // implementation...
}

// main.dart
void createData(String id, DbModel item) {
database.model.connectOrCreate(id, item);
}

Since right now I have to include a table inside the method like this:

// database
connectOrCreate<T extends Table, D extends DataClass>({
required TableInfo<T, D> table, required Insertable<D> id, required Isertable<D> item,
}) {
// Implementation...
}
// ---
// main.dart
void createData(String id, DbModel item) {
database.model.connectOrCreate(model, id, item);
// or
database.connectOrCreate(model, id, item);
}

[simolus3]

Using TableInfo to create table-agnostic queries is the way to go.

This is somewhat what I want to be able to accomplish:

If database.model.connectOrCreate(id, item); is that you would like this to look like, can't you express this as an extension on TableInfo? E.g.

extension ConnectOrCreate<T extends Table, Row> on TableInfo<T, Row> {
  Future<void> connectOrCreate(Insertable<Row> id, Insertable<Row> item) {
    // As an example for a simplified implementation.
    return this.attachedDatabase.into(this).insert(item);
  }
}

Then you could call this with database.model.connectOrCreate(id, item).

[piperun]

Wow! Thanks for the fast reply, I'll try out your suggestion!

[piperun]

The specific example you gave works without any issue, however when trying with selects, specifically trying to using .where() to filter, since the parameter within the arrow function will be of type T which means if I try and do: where((tableItem) => tableItem.id.equals(id)) I'll get:

The getter 'id' isn't defined for the type 'T'.
Try importing the library that defines 'id', correcting the name to the name of an existing getter, or defining a getter or field named 'id'.

[simolus3]

You can use schema introspection to work around these issues. That's necessarily a bit unsafe, but there's no way to represent "extensions on tables having a column named id" in Darts type system, so that's the best we can do.

[piperun]

Understood, again thank you very much for the help!