What are non key attributes?

A non key attribute in sql server is a columns which can not be used to identify a record uniquely for example name or age columns in customer table.

What is a non key attribute example?

Non-Key Attribute Two or more entities can have the same value for this attribute. For example, the Class attribute would have the same value for all those students who are studying in the same class. Example: Class, Section, Age, Name etc, are the non-key attributes.

What is the purpose of a non key attribute?

Non-prime (Non-key) attribute The values of a primary key cannot be duplicated. On the other hand, non-prime (non-key) attributes are the attributes other than the primary key attributes. They can store a value any many times. In the schema STUDENT, the attribute RegNo is the primary key (prime attribute).

What is the meaning of key attributes?

Definition(s): A distinct characteristic of an object often specified in terms of their physical traits, such as size, shape, weight, and color, etc., for real -world objects. Objects in cyberspace might have attributes describing size, type of encoding, network address, etc.

What is key attribute and example?

A key attribute is the unique characteristic of the entity. For ex. Name and hire date are attributes of the entity Employee.

What are non-prime attributes in DBMS?

Conversely, an attribute that does not occur in ANY candidate key is called a non-prime attribute. Since a relation contains no duplicate tuples, the set of all its attributes is a superkey if NULL values are not used. It follows that every relation will have at least one candidate key.

What is multivalued attribute give example?

Multivalued Attributes A multivalued attribute of an entity is an attribute that can have more than one value associated with the key of the entity. For example, a large company could have many divisions, some of them possibly in different cities.

Is name a key attribute?

Define Primary Key Attributes: For example, Name and hire date are attributes of the entity EMPLOYEE. It must have a non-null value for each instance of the entity. The value must be unique for each instance of an entity. The values must not change or become null during the life of each entity instance.

What is prime attribute example?

Attributes which are parts of any candidate key of relation are called as prime attribute, others are non-prime attributes. For Example, STUD_NO in STUDENT relation is prime attribute, others are non-prime attribute. Answer: (AE)+ = {ABECD} which is not set of all attributes. So AE is not a candidate key.

What are non key attributes in a database?

Non-key Attributes. Non-key attributes are the attributes or fields of a table, other than candidate key attributes/fields in a table.

Can a non-key attribute be dependent on a?

In a table, if attribute B is functionally dependent on A, but is not functionally dependent on a proper subset of A, then B is considered fully functional dependent on A. Hence, in a 2NF table, all non-key attributes cannot be dependent on a subset of the primary key.

How are non-key attributes defined in a 2NF table?

All non-key attributes are fully functional dependent on the primary key; In a table, if attribute B is functionally dependent on A, but is not functionally dependent on a proper subset of A, then B is considered fully functional dependent on A. Hence, in a 2NF table, all non-key attributes cannot be dependent on a subset of the primary key.

When to use non-key attributes in coursecode?

Required to retrieve a particular record from the entity table. The attribute name is underlined. Here courseCode can uniquely identify a record or a instance of COURSE entity. Attributes that are not unique (attributes other than Key Attribute). Required to store additional information about an entity.