Thank you for your post.
After you create DateA, click the "Options..." button. FileMaker takes you to a new dialog box. Click on the "Validation" tab, and check the option "Validated by calculation". You are now taken to a calculation dialog box. In the calculation formula area, enter:
DateA ≤ Get (CurrentDate)
That is, this makes sure that DateA is less than or equal to today's date.
Click "OK" to return the field options. At the top of that screen, under "Validate data in this field", select "Always". Also, unless you want the ability to override the entry, uncheck the option "Allow user to override during data entry". This forces the user to always put in dates that meet the criteria.
Click "OK" to return to the Fields dialog box.
Follow the same steps above for DateB, except in the calculation formula area, enter:
DateB ≥ DateA
Now, you will be able to enter any data you want, and when you try to commit the record, FileMaker will perform the evaluation on this field, and if the criteria is not met, and error message will appear.
Thank you, TSGal
I am trying to solve the exact same issue and I have a follow-up question:
I can get the "DateB ≥ DateA" validation to work, but how do you tell it:
DateB ≥ DateA unless DateA is empty, then don't evaluate/don't show the error message
I have a series of due dates that I need to daisy-chain in this manner. It works fine if I enter all the dates at once, but some fields will remain blank until the user inputs the due date. Right now the user tries to enter the DateA date, but gets an error if DateB is blank.
Validation should be:
DateB ≥ DateA or IsEmpty ( DateA )