How does data validation works in table?

Praneeth_143663

1. -We have added a column in Table and have made it mandatory, however this doesnt work as the form will be submitted even though the column is blank.
2. One of the column is changed to Type 'Files' and we have added the validation to allow only pdf files to be uploaded - However, the field allows user to upload any files.

Christina_108366

I would also be very interested in an answer

Anna_272419

Following for answer as well.