在ArangoDB中进行EXISTS查询的最佳方法是什么

LET count = COUNT(
  FOR doc IN your_collection
  FILTER doc.some_field == 'some_value'
  RETURN doc
)
RETURN count > 0

RETURN LENGTH(
  FOR doc IN your_collection
  FILTER doc.some_field == 'some_value'
  LIMIT 1
  RETURN 1
) > 0

RETURN DOCUMENT('your_collection/your_document_key') != null

FOR doc IN your_collection
FILTER HAS(doc, 'nested_property')
RETURN doc

FOR doc IN your_collection
FILTER 'some_value' IN doc.some_array
RETURN doc

db.your_collection.ensureIndex({ type: "hash", fields: ["some_field"] });

LET count = COUNT(
  FOR user IN users
  FILTER user.username == 'john_doe'
  RETURN user
)
RETURN count > 0

RETURN LENGTH(
  FOR user IN users
  FILTER user.username == 'john_doe'
  LIMIT 1
  RETURN 1
) > 0

RETURN DOCUMENT('users/john_doe') != null