Returns unique fields for a command as a list of tuples as: {field_name :: atom() | list(atom), error_message :: String.t(), owner :: term, opts :: keyword()}, where opts might contain none, one or multiple options: ignore_case: true or ignore_case: [:email, :username] for multi-fields entities - binary-based fields are downcased before comparison :label - use this atom as error label :is_unique - (term, String.t(), term, keyword() -> boolean()) :partition - use to set custom partition name :no_owner - if true then ignore owner and check field_name - field_value pair uniqueness in a partition scope. release_by_value/3 must be used to release key-value pair in such case.

:no_owner option has sense when it is necessary to ensure uniquenesses in embedded structs.