Define partial key and primary key, Database Management System

Assignment Help:

Define Partial Key and Primary Key

A partial key, also known as discriminator, is the set of attributes which can uniquely identify weak entities that are related to similar owner entity. Primary key is a unique key but not comprise null values. An entity set can comprise at most one primary key.


Related Discussions:- Define partial key and primary key

What is a shadow copy scheme, What is a shadow copy scheme? It is simpl...

What is a shadow copy scheme? It is simple, but efficient, scheme known as the shadow copy schemes. It is based on making copies of the database called shadow copies that singl

Derived horizontal fragmentation, atient(PNumber, Name, NHS_no, Amount_due,...

atient(PNumber, Name, NHS_no, Amount_due, DNO, Doctor, Medical_Treatment), relation of schema Staff(StaffNum, Name, DNO, Task) and relation of schema Dept(DNO, Name, Location, Dire

Deadlock and its prevention, Deadlock And Its Prevention: As seen earlier,...

Deadlock And Its Prevention: As seen earlier, though two phase locking protocol handles the trouble of serialisability, but it causes some troubles also. For instance, consider th

Define value set, Define value set? Value set: It is a set of values. Y...

Define value set? Value set: It is a set of values. You do not always need a user to enter junk free text within all the fields. Therefore, Oracle Apps uses value set to valida

State the objectives of object design, Determine the OBJECTIVES of  object ...

Determine the OBJECTIVES of  object design After passing through this unit, you should be able to: describe and apply concept of generalisation; understand and appl

Hashing.., various techniques of hashing?

various techniques of hashing?

Transaction, .#question. Discuss the problem which may arise during concurr...

.#question. Discuss the problem which may arise during concurrency control and recovery in distributed database which are not encountered in controlized database environment.

Describe association design of an object, Describe association design of an...

Describe association design of an object by giving one suitable example of it. The Design of Associations Associations are "glue" of advanced object oriented analysis and

Represent the form as a relational schema, Question: This form represen...

Question: This form represents one of a number used for each sailing of a range of boats. A passenger may go on many sailings and will have the same passenger number for each.

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd