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

Define a property that is not a property of transactions, Define a property...

Define a property that is not a property of transactions? Ans: Concurrency is not a property of transactions

Self-join, Self-Join:   In a self join a table is joined with itself.  Let ...

Self-Join:   In a self join a table is joined with itself.  Let consider the following sample partial data of EMP table EMPNO ENAME MGRID

What is an object id, What is an object ID? Each class-derived table ha...

What is an object ID? Each class-derived table has an ID for primary key, one or more object IDs form primary key for association derived tables. An object ID is equivalent dat

Create student db and execute insert query, Create Student DB and execute I...

Create Student DB and execute Insert query? STUDENT (name, student#, class, major) COURSE (course name, course#, credit hours, department) SECTION (section identifier, course

Differentiate between a global and a local temporary table, Differentiate b...

Differentiate between a Global and a Local temporary table? - A local temporary table exists only for the duration of a connection or if defined inside a compound statement, fo

Define upgrade and downgrade, Define upgrade and downgrade? It gives a ...

Define upgrade and downgrade? It gives a mechanism for conversion from shared lock to exclusive lock is called as upgrade. It gives a mechanism for conversion from exclusive

Explain an attributes, What are attributes? Give examples. An entity is...

What are attributes? Give examples. An entity is shown by a set of attributes. Attributes are descriptive properties possessed by every member of an entity set. Example: pos

Structure of distributed database, Structure Of Distributed Database: A di...

Structure Of Distributed Database: A distributed database system haves of a collection of sites, each of which keeps a local databases system. Every site is able to process local

Datawarehouse, 1) Define a job scheduling strategy that will meet business ...

1) Define a job scheduling strategy that will meet business requirement of reporting availability by 6am CST for the following cubes? Show the job scheduling dependencies in a pict

Group by clauses-data manipulation language, Group By clauses  • It is ...

Group By clauses  • It is used to group database tuples on the basis of definite common attribute value like as employees of a department. WHERE clause still can be used

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