$countSameRooms

Counts how many other Rooms in the model share the same Room Number as the given Room. Used to detect duplicate room numbers.

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Definition

$countSameRooms := function($roomNumber, $roomId){
  $count($Rooms[values.number = $roomNumber and id != $roomId])
};

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Dependencies

Requires $Rooms to be defined in the outer scope:

$Rooms := $[type = "Room"];

Pre-collecting all rooms into a variable avoids re-evaluating the full dataset filter for every room.

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Parameters

Parameter	Type	Description
$roomNumber	string/number	The number of the room being checked
$roomId	number	The id of the room being checked — excluded from the count so a room does not count itself

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Return value

A number: 0 if the number is unique, 1 or higher if duplicates exist.

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Usage

(
  $Rooms := $[type = "Room"];

  $countSameRooms := function($roomNumber, $roomId){
    $count($Rooms[values.number = $roomNumber and id != $roomId])
  };

  $[type = "Room"].{
    "id": id,
    "name": name,
    "number": values.number,
    "numOfOtherRooms": $countSameRooms(values.number, id)
  }
)

Validator: numOfOtherRooms → int:EqualTo 0

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Used in rules

• rule-b2b611d9 — Room number is uniek