8 Replies Latest reply on Nov 16, 2012 8:22 AM by philmodjunk

    Repeating Field usage

    snimmo

      Title

      Repeating Field usage

      Post

           I have heard a lot of conversation about using or not using repeating fields and would like some guidance on a particular need.

           I am trying to replicate an application I developed in Access which used some array calculations and was wondering if this would be, indeed, one of those situations where repeating fields would make sense.

           The application has three groups of ten fields in a single record. One group of values is predetermined and represents a weighting of each occurance, one group is entered by the user and the last group gets calculated using the first two groups. Each field withing a group acts exactly the same and the formula for the calculation would be exactly the same. It would be advantagous to be able to call a custom function by looping through each of the ten iterations of fields like you would with an array instead of having to code each field calculation individually.

           There will probably be numerous situations where comparisons or calculations might occur on these three groups of fields but again each occurance of the fields in any given group would react the same as any other occurance within the same group.

           Maybe there is a better way to do this within Filemaker but if so I haven't stumbled across it yet.

           Any help or alternative solution would be welcome.

           Thank you.

        • 1. Re: Repeating Field usage
          philmodjunk

               What you describe is a bit vague, but still sounds like something that can be done with a set of related records. There are at several ways that a calculation in one record can reference a value in another record.

          • 2. Re: Repeating Field usage
            snimmo

                 It does seem possible that related records might work but the I/O involved could get very extensive if you had thirty records to read/write vs one if these fields were in the same record.

                 Maybe I can give a better example;

                 Group a: range is 1 to 10

                 Group b: ten decimals totalling up to 1.0

                 Group c: calculated by multiplying group a(1) * group b(1) to get group c(1),  a(2) * b(2) to get c(2) etc.

                  

                 A: 1  5  5  4  6  8  5  4  6  9

                 B: .1  .1.  .05  .1  .15  .05  .15 .1  .1  .1

                 Result

                 C .1  .5  .25  .4  .9  .4  .75  .4  .6  .9

                 If a, b and c were all in one record then you have one I/O but if you use related records you would have 30 I/O operations. The fact that there might be even more calculations against all groups would require even more I/O operations. That is why it would seem more practical to put those in one record.

            • 3. Re: Repeating Field usage
              philmodjunk

                   So you create 10 records with an a, b, c field in each record.

                   Then a calculation field: a * b * c will compute the product of the three.

                   Don't see any advantages to using a repeating field for that.

              • 4. Re: Repeating Field usage
                snimmo

                     If you have a hundred people filling in these records and you need ten records instead of one that would result in 1000 I/O operations on the database as opposed to 10. Wouldn't that be a disadvantage and I/O operations grow significantly as the number of users increased?

                • 5. Re: Repeating Field usage
                  philmodjunk

                       It's the same number of I/O operations. one I/O operation on one repetition will = one I/O operation on one field in a record.

                       Meanwhile, you have many built in tools for working with aggregate groups of records, only a few of which work with a repeating field.

                  • 6. Re: Repeating Field usage
                    RickWhitelaw

                         I agree with Phil. Repeating fields or not, there's no free lunch in the I/O department. I use repeating fields for certain displays but occasionally get bitten when I discover later that I need to use them in calculations. A lot of extra work with no benefit.

                    • 7. Re: Repeating Field usage
                      snimmo

                           Thanks for the posts on this issue. I will try to take your advice and avoid the repeating fields. Just wanted to confirm some of the feedback I had heard and put it into my own situation.

                            

                           Thanks again.

                      • 8. Re: Repeating Field usage
                        philmodjunk

                             Please Note: I DO use repeating fields, but only if there is s clear cut advantage to doing so and such uses are few and far between these days. Repeating fields were, back in FileMaker Pro 2.5 the only way to associate groups of data with a given record--the database was not a relational database. Filemaker has maintained backwards compatibility ever since, but with each new release repeating fields are less and less useful.