A couple of simple queries regarding validation

[fmow]

a. I am having a hard time understanding the difference denoted in fmp help wrt to the following: "For Validation options for this field, select Always for ongoing field validation, or Only during data entry to limit validation to instances when data is being entered."

 

b. I am setting a field to Date type. And fmp also offers the option of a "strict data type" which I can set as 4 digit date. I am not sure what this adds to the validation process since the field is already in a so to speak strict data mode via fmp's default 4 digit date format. Surely, it does adds something, but I can't figure out what. 

[IdealData]

a. Records can be updated from script interaction without a user actually typing anything. Sometimes (mostly) it is not desirable to have scripted routines subject to data validation, so you would select 'Only during data entry'

 

b. Date formats can be as simple as xx/xx/xx, but strict format ensures the use of 4 digit years. 4 digits are required to differentiate between centuries, otherwise FMP applies a rule to determine which century a 2 digit year should fall in.