Field Properties Through Conditional Statement

[Stew]

I am looking to set up a on update command on a field. They can chose one of 5 options, 2 of which requires dates involved. I'd like to enable the date fields for editing when those options are chosen, and make them required fields. And when the other 3 options are chosen I'd like the dates to clear out and no longer be enabled. Just wanted to know if this is possible. I've been searching through the SQL code but couldn't find these properties to set.

[HansV]

You can only do this in a form, not in a table.
Check out the Enabled, Locked and Visible properties of the text box control.