4 Replies Latest reply on Feb 29, 2012 9:46 PM by GraemeC

    Incomplete dates of birth

    GraemeC

      A database recording people's details in a situation where providing data is not compulsory for membership raises the question of how to handle partial dates of birth. Some people are happy to provide their full day-month-year date of birth. Some are happy to provide their birthday as day-month or just month. Others wish to keep their birthday to themselves but are happy to give the year that they were born.

       

      I am about to retrofit something like this into one of my databases. The most obvious way is to have three fields, one for each of day, month, and year, and to turn the existing birthdate field into a calculation based on the three separate fields. That should allow calculation of ages accurately in some cases, approximately in some cases, unknown in other cases. It should also allow listing of forthcoming birthdays, precisely in some cases, approximately in some cases, unknown in other cases. (If people refrain from providing full details they can't complain if their birthday is not noticed, but they have the option of keeping some data private if they wish to.)

       

      Does anyone have any better suggestions for handling partial dates of birth than the above?

        • 1. Re: Incomplete dates of birth
          Malcolm

          A database recording people's details in a situation where providing data is not compulsory for membership raises the question of how to handle partial dates of birth.

           

          As you suggest, a field for each component and a calculation. You may want additional fields to support an age range.

           

          Many people don't remember the day, month or year of birth. You can end up with two fields for each element.

           

          From the data you'll end up creating a low date and a high date.

           

          Malcolm

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          • 2. Re: Incomplete dates of birth
            GraemeC

            Pairs of fields to get a date range might be a bit of an overkill, but I might just do that.

             

            Many thanks, Graeme

            • 3. Re: Incomplete dates of birth
              Malcolm

              Pairs of fields to get a date range might be a bit of an overkill, but I might just do that.

               

              At first glance it does but you may need even more if you are going to handle every contingency.

               

              How do you accurately track the estimate made by someone who says "I was born in May. It was 1932 or 1933". It's not accurate to  say the 1st May 1932 to 31st May 1933. It is most accurate to say 1st May 1932 to 31st May 1932 or 1st May 1933 to 31st May 1933. On top of that, the only certainty is May.

               

              you end up with something like this:

               

              actual Day

              actual Month : May

              actual Year

               

              alt Day

              alt Month

              alt Year : 1932

               

              alt Day

              alt Month

              alt Year : 1933

               

              It gets complicated fast. In most applications it isn't worth the headache. Find out what the needs are and shortcut the process to fit them.

               

              Malcolm

              1 of 1 people found this helpful
              • 4. Re: Incomplete dates of birth
                GraemeC

                In my case it is not that people don't know their dates of birth, but how much of the data they want to provide. So what they do provide will normally be reliable and I'll stick with just three fields for the parts of the date and a number of calculation fields depending on the use to be made of the data.

                 

                Many thanks, Graeme