What is the difference between primary key and super key ?

[sameergupta]

Hi

What is the difference between primary key and super key ?

[mariaandreson]

Primary key has two properties * uniqueness. * not null value acceptable.

Where as super key is candidate key minus primary key attributes.

[bababangali]

Super Key - An attribute or set of attributes that uniquely identifies a tuple within a relation

Primary key -The candidate key that is selected to identify tuples uniquely within the relation, the candidate keys which are not selected as PKs are called "Alternate keys"

[angilpari1122]

A primary key is a candidate key that you tell the DB to optimize on. There might be multiple ways of referring to a unique tuple (ie. multiple candidate keys) but you can specify one when you're creating the table that you will use the most frequently.
A super key is a set of fields that contains a key.

[karankasyup]

PRIMARY KEY:-A primary key is a field that uniquely identifies each record in a table. As it uniquely identify each entity, it cannot contain null value and duplicate value.

SUPER KEY :- If we add additional attributes to a primary key, the resulting combination would still uniquely identify an instance of the entity set. Such augmented keys are called superkey.

[uditsh]

Primary Key- Any one of candidate key that uniquely identifies record in a table. (not null + unique)
Super Key- Set of attributes that uniquely identifies a record in a table.

[eastman]

A Super Key is simply a non-minimal Candidate Key, that is to say one with additional columns not strictly required to ensure uniqueness of the row.
A Primary Key is a minimal Candidate Key, which is to say all constituent columns are strictly required in order to ensure uniqueness.

[Maryjgodfrey]

What is the difference between primary key and super key ?

Equivalently a super key can also be defined as a set of attributes of a relation schema upon which all attributes of the schema are functionally dependent. Candidate Key- minimal of super key that uniquely identifies a record in a table. Primary Key- Any one of candidate key that uniquely identifies a scholarship essay writing help from clazwork record in a table.

[Rosa]

Both primary and super keys are used to identify a record in a table. Primary key is one of the candidates key.

[pihu]

Super Key - An attribute or set of attributes that uniquely identifies a row within a relation or table


Primary key -The candidate key that is selected to identify row uniquely within the relation, the candidate keys which are not selected as PK are called "Alternate keys"