You would need to do a db search for the documents but the problem is that that search would be quite slow
an when the number of documents increases in the database the search would be slower and slower.
But It all depends on how many documents you are expecting.
I would compute a text field with the date written in ISO format YYYY-MM-DD because that type of date can be sorted as text.
And the search in the database is much faster because it's text.
I normally don't suggest that you write dates as text but if you are going to do searches date fields are not optimal at all.