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db design to calculate overlap in group membership in time
Hi all,
I am a biologist studying the social structure of birds. I am currently brainstorming ideas for constructing a database that will allow me to easily calculate the number of seconds that one bird is in the same group as another bird. Because group membership changes frequently with birds arriving and departing at different times, and often arriving, departing, and re-arriving on the scale of seconds, I will have many thousands of records. I am trying to determine how to best set up this database before entering all the data. I have 2 goals with this database: 1) I need to find a way that I can streamline data entry. I was thinking 3 columns: ID, time of movement, and whether it is an arrival or departure. Because of the frequent movements and the large number of potential individuals, I need to be able to enter arrivals and departures separately. 2) I need to determine how I am going to calculate the amount of time that any 2 birds at present at the same time. This needs to be able to account for individuals that arrive and depart at different times, and calculate just "shared" time. I think this problem may be somewhat similar to company records of employees hired and fired at different dates, where the amount of time of overlap in employment is calculated. Any help or advice would be greatly appreciated! Thanks, Liz |
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