Dart APIunself_local_databaseFieldDatatype type property Null safety FieldType type final Implementation final FieldType type; unself_local_database unself_local_database FieldData type property FieldData class Constructors FieldData fromJson Properties collectionId created extra hashCode id name required runtimeType system type unique updated Methods copyWith noSuchMethod toColumns toCompanion toJson toJsonString toString Operators operator ==