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Super Key in DBMS
Super Key
In this article, we will learn about Super Key in DBMS.
Super key is a set of one or more attributes in a table that can uniquely identify each record present in a table.
Super Key in DBMS
- A super key is a group of single or multiple keys which uniquely identifies rows in a table.
- A Super key may have additional attributes not needed for unique identification.
Example of the super key
Consider the following table student| ID | NAME | PHONE | AGE |
|---|---|---|---|
| 66 | John | 7832973477 | 23 |
| 67 | Judy | 9732867464 | 21 |
| 68 | Elena | 8923826476 | 25 |
| 69 | John | 7326247844 | 23 |
The possible set of SuperKeys –
[ID]:
Asno two students will have the same Id, it will help to uniquely access the student details, hence it is a super key. Now we will identify all the Super Keys present in the table that is the set of attributes that will help to uniquely access a record[NAME, ID]:
Even if more than one student has the same name then the combination name will help to recognize the record, as student id will break the tie and this is combination is a super key[PHONE]:
As no two students will have the same phone number, a phone number will help to uniquely access the student details and hence phone number is a super keyPrime Course Trailer
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Super Key in DBMS
- A super key is a group of single or multiple keys which uniquely identifies rows in a table.
- A Super key may have additional attributes not needed for unique identification.
Example of the super key
Consider the following table student
| ID | NAME | PHONE | AGE |
|---|---|---|---|
| 66 | John | 7832973477 | 23 |
| 67 | Judy | 9732867464 | 21 |
| 68 | Elena | 8923826476 | 25 |
| 69 | John | 7326247844 | 23 |
The possible set of SuperKeys –
[ID]:
Asno two students will have the same Id, it will help to uniquely access the student details, hence it is a super key. Now we will identify all the Super Keys present in the table that is the set of attributes that will help to uniquely access a record
[NAME, ID]:
Even if more than one student has the same name then the combination name will help to recognize the record, as student id will break the tie and this is combination is a super key
[PHONE]:
As no two students will have the same phone number, a phone number will help to uniquely access the student details and hence phone number is a super key
Prime Course Trailer
Related Banners
Get PrepInsta Prime & get Access to all 200+ courses offered by PrepInsta in One Subscription
Get over 200+ course One Subscription
Courses like AI/ML, Cloud Computing, Ethical Hacking, C, C++, Java, Python, DSA (All Languages), Competitive Coding (All Languages), TCS, Infosys, Wipro, Amazon, DBMS, SQL and others
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