DELPHI-Fehler in Master/Detail-Verknüfungem über MasterFields

[Uwe Raabe]

FireDAC ist da ziemlich flexibel: Master-Detail Relationship (M/D)

Wichtig dabei ist dieser Abschnitt:

Zitat:

So how does it work? FireDAC builds for qOrderDetails a list of pairs - qOrders fields and qOrderDetails parameters. Elements in each pair:

When MasterFields is not specified, then they have the same name;
Otherwise, the pair elements have the same position, the same fields in the MasterFields list, and the same parameters in the Params collection.
When the current qOrders record is changed, FireDAC assigns for each parameter a corresponding field value. In our case, qOrderDetails :OrderID parameter gets the qOrder OrderID field value. After that, the qOrders is reexecuted.