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Start your free trialYao Tung Ooi
13,744 PointsIn the case where you updated all emails to anon@email.com, what happens if the email field is a unique key?
In the case where you updated all emails to anon@email.com, what happens if the email field is a unique key?
1 Answer
Steven Parker
231,184 PointsIf a field is a unique key, then any attempt to write a value into a row that already exists in another row will fail and produce an error message.
Another result of making a field a unique key is that is cannot be optional. There can be at most one row where the field is null, in all other rows a unique value must be part of the record when it is inserted.
Yao Tung Ooi
13,744 PointsYao Tung Ooi
13,744 PointsThank you!