>>The responsibility is on the operator - and for that purpose, the app can only offer to show some history of both records.
>>
>>I once had to have such a routine in the app from the beginning, because of the nature of the matter. It was a walk-in hospital, where they would, at times, have to accept unidentified patients - crash victims, drunks, newborns - and assign them temporary IDs, and maybe later add some personal data. Months or years later, this person would come again with regular papers, someone would enter the data from there, and then somehow it would be revealed that this "new" patient has history - which was then attached using this routine.
>
>Agreed - but the different data might be in last years children already packed away to the data store
>and not available in current year - you remember those systems...

Not fond memories... But it's just an additional complication.

In this case (fpd2.6, '94-96), the transactions were separated by year of birth modulo 100, which made separation by year of event unnecessary. The additional complication was the case when the other patient was in another year, but I made the routines separate enough, so it didn't matter.