defaultValue property Null safety
final
        The default value of the property.
By default, a property does not have a default property. This is a String to be interpreted by the database driver. For example, a PostgreSQL datetime column that defaults to the current time:
    class User extends ManagedObject<_User> implements _User {}
    class _User {
      @Column(defaultValue: "now()")
      DateTime createdDate;
      ...
    }
Implementation
final String? defaultValue;