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Self Join help


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Hi there

Am creating a database of children's heights. Have a main table with each child's name and age - call it CHILDREN

Each time I see the child I measure their height and weight which are entered into a new table call it GROWTH

What i need is when I measure the height on this occasion I want the date of the last measured height ON THIS CHILD to be automatically entered into the record for this occasion.

I think I need a self join relationship but am not sure how to set it up so that the height is automatically entered.

All help appreciated.

Craig McDonald

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Set up a self-join, by creating a new TO for the Growth table (like Growth_selfPrevious), and connect it to another TO of Growth via childID_kf = childID_kf and dateMeasurement > dateMeasurement; sort the records from the new TO by date, descending. This means that the first record via that relationship is the last measurement before the current one.

Then set up an auto-enter calculation for the height field, with Growth_selfPrevious::height as the result. Make sure you use the other Growth TO as the context for the evaluation.

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