Option to use joins instead of multiple calls for relations.

Suggestion

An option to use joins instead of multiple calls for relations would be useful for performance reasons and would also not effect multi datasources setups by default.

Use Cases

We are using a lot of DB calls with nested relations and each of those relations are fetched using extra DB calls which could be avoided. I understand the reasoning behind not using joins but I believe there should at least be an option to include relations through joins when required.

Examples

The syntax could be something like this -

"include": [
{
"relation": "child",
"join": "true"
}
],

or this could be defined at the model level in the relation decorator.

Acceptance criteria

TBD - will be filled by the team.

In der Issue werden keine Dateien, Tests, Einstiegspunkte oder Abnahmekriterien genannt. Beginne damit, zu prüfen, wie relation includes und PostgreSQL-Abfragen derzeit behandelt werden, und kläre anschließend die Join-Syntax, das Verhalten auf Modellebene, die Einschränkungen für mehrere Datenquellen und die erforderlichen Tests, bevor die Implementierung als abgeschlossen betrachtet werden kann.