one-to-one relationship

[alex12]

What is “time dependent one-to-one relationship”? With such relationship can table have different number of records?
Thanks.

 

[ClayG]

I THINK it probably means the relationship is 1:many over time, and given a specific time it is 1:1.
E.G. An Employee could have only one Location at a time.
..?

 

[alex12]

With one-to-one relationship the tables on both sides must have the same number of records or not?
Thanks.

 

[SQLScholar]

I dont think so.

Surely one table can have say 2000 records, but some of the records may not link to the other table, and others may link to other tables.

The only thing that must be is that one record can only link to one other record on that table.

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