Can a non-prime attribute determine a prime attribute?

Can a non-prime attribute determine a prime attribute?

Non prime attribute is an attribute that is not part of any candidate key. So, its advisable that you find out all possible candidate keys from the given functional dependencies and mark the prime and non prime attributes. If ‘A’ is a non prime attribute, it can determine a prime/non prime attribute.

When a non-prime attribute is functionally dependent on part of a candidate key?

A relation is in the second normal form if it fulfills the following two requirements: It is in first normal form. It does not have any non-prime attribute that is functionally dependent on any proper subset of any candidate key of the relation.

How do you find non prime attributes?

Non prime attributes also called as Non Key attributes….

1. [ID] : Every individual will have a unique ID so it is a prime attribute.
2. [NAME] : Two different persons might have same name, so it is non prime attribute.
3. [AGE] : Two different persons might have same age, so it is non prime attribute.

Which normal form dictates that all non key attributes of a table must be fully functionally dependent on a candidate key?

Second Normal Form
A relation that is in First Normal Form and every non-primary-key attribute is fully functionally dependent on the primary key, then the relation is in Second Normal Form (2NF). Note – If the proper subset of candidate key determines non-prime attribute, it is called partial dependency.

What are the differences between prime and non-prime attribute?

Prime attribute: Prime attribute is the attribute which is the part of the candidate key. Non -prime attribute is the attribute which is not the part of the candidate key. …

What do you mean by prime attribute?

Prime attributes are the attributes of the candidate key which defines the uniqueness (Eg: SSN number in an employee database) A primary key is a column in a table whose values uniquely identify the rows in the table.

Can a table in 2nd normal form have a FD in which the non prime?

So, if you add attributes on the left side nothing changes with respect to the definition of 2NF, the only important thing is that a non prime attribute cannot depend on a proper subset of a candidate key. Can’t one non prime attribute just be dependent on another non prime attribute?

When is a table in 2nd normal form?

Note that if the primary key is not a composite key, all non-key attributes are always fully functional dependent on the primary key. A table that is in 1st normal form and contains only a single key as the primary key is automatically in 2nd normal form.

Which is a non-key attribute in second normal form?

The non-key attribute is [Purchase Location]. In this case, [Purchase Location] only depends on [Store ID], which is only part of the primary key. Therefore, this table does not satisfy second normal form. To bring this table to second normal form, we break the table into two tables, and now we have the following:

Can a 2NF table be dependent on a composite key?

Hence, in a 2NF table, all non-key attributes cannot be dependent on a subset of the primary key. Note that if the primary key is not a composite key, all non-key attributes are always fully functional dependent on the primary key.