In a Students table with columns StudentID, FirstName, LastName, and Email, which combination of columns can be considered a super key?
Question
In a Students table with columns StudentID, FirstName, LastName, and Email, which combination of columns can be considered a super key?
Solution
A super key in a database is a group of single or multiple keys which identifies rows in a table. It's a set of attributes, the values of which can be used to uniquely identify a database record.
In the Students table with columns StudentID, FirstName, LastName, and Email, the following combinations can be considered as super keys:
- {StudentID, FirstName, LastName, Email}
- {StudentID, FirstName, LastName}
- {StudentID, FirstName, Email}
- {StudentID, LastName, Email}
- {FirstName, LastName, Email}
- {StudentID, Email}
- {StudentID, FirstName}
- {StudentID, LastName}
- {StudentID}
The minimum super key is {StudentID} if StudentID is unique for every student.
Please note that the above combinations assume that the values are unique across the rows in the table. If there is a possibility of duplicate values, then those combinations cannot be considered as super keys.
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