I've got on my hands a paper database with records from 1955 to now. Recordkeeping was sloppy for a long time, up until 1984. Handwritten cards often had just month and year since the date wasn't considered that important, but rubber stamped cards would have full date. A few cards suffer from smudges, poor handwriting, etc. but not that many.

It would be great if a database would accept 1971/8/0 as August ??, 1971 and 1959/0/0 if only the year is extant (probably few or no such cards). Making separate day/month/year columns seems workable if not a little unwieldy. Are there better ways to handle the situation?

mysql does

In any database platform, you should be able to default records with missing years to a default year, and records with missing dates to January 1st. The logic is not complex, but you will need to apply it as the records are being inserted.