How to enter incomplete or partial date with date module? (Day-Month-Year / Month-Year / Year) I have a content type A and it has a date field.

I'm selecting Day-Month-Year for this date field. But not every content has a day and I want to select only Month and Year for these content.

If I select (enter) only month and year, it gives error:


  The value input for field Date is invalid: The value March 1979 does
  not match the expected format.



I installed and tried the Partial Date module but still couldn't do what I want although it says on the module page: 


  This module provides date and time fields that allows any individual
  component to be left blank, while still providing a sortable listing
  of the fields.



How can I do that? I want to enter full date (Day-Month-Year) for some nodes and for some others partial date (only Month-Year) and maybe for some others only Year. Isn't this possible?


Day-Month-Year
Month-Year
Year


(And also there is an unsolved issue about this: Allow "fuzzy" granularity.)
It is not possible with one date field. But you can achieve it by adding two different date fields with different configuration i.e.:


Date, Month and Year for Date1 field.
only Month and Year for Date2 field.