What is super key candidate key and primary key?

Super Key – A super key is a group of single or multiple keys which identifies rows in a table. Primary Key – is a column or group of columns in a table that uniquely identify every row in that table. Candidate Key – is a set of attributes that uniquely identify tuples in a table.

What is the difference between super key and candidate key?

Super Key is a set of attributes or columns that uniquely identifies each row table whereas, a candidate key is a set of attributes that recognizes the tuples in a relation, or table.

What is the relationship between super key and candidate key?

Super Key is used to identify all the records in a relation. Candidate key is a subset of Super Key. All super keys can’t be candidate keys. All candidate keys are super keys.

What is a super key in DBMS?

Super key is a single key or a group of multiple keys that can uniquely identify tuples in a table. Super keys can contain redundant attributes that might not be important for identifying tuples. Candidate keys are a subset of Super keys.

What is candidate key?

A candidate key is a specific type of field in a relational database that can identify each unique record independently of any other data. Experts describe a candidate key of having “no redundant attributes” and being a “minimal representation of a tuple” in a relational database table.

What is the another name of super key?

Super key is an alternative name for the Windows key or Command key when using Linux or BSD operating systems or software.

What is the difference between super key and composite key?

A super key uniquely identifies a row. It could be made up of one column or many. A composite key is a key made of more than one column. If a Super Key is made of more than one column it is also a composite.

What is a Superkey example?

A super key is a superset of a candidate key. For example: In the above EMPLOYEE table, for(EMPLOEE_ID, EMPLOYEE_NAME), the name of two employees can be the same, but their EMPLYEE_ID can’t be the same. Hence, this combination can also be a key. The super key would be EMPLOYEE-ID (EMPLOYEE_ID, EMPLOYEE-NAME), etc.

What is candidate key with example?

Candidate Key: The minimal set of attributes that can uniquely identify a tuple is known as a candidate key. For Example, STUD_NO in STUDENT relation. *It is a minimal super key. *It is a super key with no repeated data is called as candidate key.

What is primary key and example?

A primary key is a column — or a group of columns — in a table that uniquely identifies the rows in that table. For example, in the table below, CustomerNo, which displays the ID number assigned to different customers, is the primary key. CUSTOMERS. CustomerNo.

What is super key give an example?

Super Key: The set of attributes that can uniquely identify a tuple is known as Super Key. For Example, STUD_NO, (STUD_NO, STUD_NAME), etc. rows in a table. * It supports NULL values.