Update Events for Aggregate Calculations are Lost for External Data Sources
Operating system version
Mac OS X 10.9.2
Description of the issue
Suppose a "data separation model" FileMaker solution, where one file contains all data and another contains just the user-interface -- connected to the data file via an External Data Source.
If the data file contains a calculation Field which uses the "Count" function to count related records, the calculation result updates correctly in data file layouts, but does not update in the UI file until the field is clicked.
Update events from the data file are not being sent to the UI file via the External Data Source facility. They are lost.
This problem does _not_ occur for other kinds of fields (numeric, text, etc.) nor for calculation fields that use other functions (simple arithmetic, for example). For those, updates in the data file are properly tracked in the UI file.
Steps to reproduce the problem
See my test files that demonstrate the problem:
Also, see this FM forum discussion:
If a calculation field displays a correct result in one layout in one file, that same calculation field for that same record in a External Data Sourced file should display the same result.
For aggregate functions such as "Count", the correct updated calculation result is _not_ displayed correctly in the UI file until the user clicks in the _calculation_ field there to force an update, or until the user's window is refreshed by some other means.
Either use a timer to force a window refresh periodically (kludgey, inefficient, inaccurate), or just don't use External Data Sources, because they do not work reliably with aggregate function-based calculations.