Differentiate between a unique key and a primary key, Database Management System

Assignment Help:

Differentiate between a unique key and a primary key.

- By default, clustered index on column are created by primary key while nonclustered index are created by unique key.

- Primary key doesn't allow NULLs however unique key allows one NULL.

 


Related Discussions:- Differentiate between a unique key and a primary key

Determine the two special events, What are two special events? The two ...

What are two special events? The two special events are as "entry" and "exit". Any action which is marked as linked to entry event is executed whenever given state is entered v

Distributed control and data sharing , Distributed Control and Data sharing...

Distributed Control and Data sharing: The geographical distribution of an organization can be showed in the distribution of the data; if a number of different sites are linked to e

What count function return in sql, What Count function return in SQL? C...

What Count function return in SQL? Count function within SQL returns the number of values. (Count function counts all the not null values in the exact column. If we need to cou

What is recovery management component, What is recovery management componen...

What is recovery management component? Ensuring durability is the responsibility of a software component of the base system known as the recovery management component.

Define average seek time, Define average seek time. The average seek ti...

Define average seek time. The average seek time is the average of the seek times, calculated over a sequence of random requests.

Lock, intent locking

intent locking

Components of database manager, Components of database manager The ab...

Components of database manager The above functions are reached by the database manager. The major elements of a database manager are: Authorisation control: This mod

Explain the b+ tree, Explain the B + tree? B + tree is a type of tre...

Explain the B + tree? B + tree is a type of tree which denotes sorted data in a way that permits for efficient insertion, retrieval and removal of records, each of which is

Enterprise applications integration, The figure below depicts the conceptu...

The figure below depicts the conceptual diagram of a banking system. (a) Describe one example relevant to the system in figure, for each of the 4 types of enterprise appl

Give expression in both tuple calculus and domain calculus, Consider the fo...

Consider the following relational schema: Doctor(DName,Reg_no) Patient(Pname, Disease) Assigned_To (Pname,Dname) Give expression in both Tuple calculus and Domain calculus for

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