What are partial and natural key, Database Management System

Assignment Help:

What are partial, alternate,, artificial, compound and natural key?

Partial Key: It is a set of attributes that can uniquely recognize weak entities and that are related to same owner entity. It is sometime known as Discriminator.

Alternate Key: All Candidate Keys excluding the Primary Key are called as Alternate Keys.

Artificial Key: If no obvious key either stands alone or compound is available, then the last resort is to simply make a key, by assigning a unique number to every record or occurrence. Then this is known as developing an artificial key.

Compound Key: If no single data element uniquely identifies occurrences within a construct, then combining multiple elements to make a unique identifier for the construct is known as creating a compound key.

Natural Key: When one of the data elements stored within a construct is utilized as the primary key, then it is known as the natural key.

 


Related Discussions:- What are partial and natural key

What is candidate key, What is candidate key? Candidate Key - A candi...

What is candidate key? Candidate Key - A candidate key of an entity set is a minimal superkey, which uniquely identifies each row in the relation.

In which format database schema is written, In which format database schema...

In which format database schema is written ? Data base schema is written in the DDL format.

Define physical and logical data independence, Define physical and logical ...

Define physical and logical data independence. How does this architecture help in achieving these? Data independence entails that change in one view must not need a change in t

Research in Concurency Control Protocols, Performance of Various Concurrenc...

Performance of Various Concurrency Control Mechanisms

Differance between unordered and ordered file, Differance between Unordered...

Differance between Unordered and ordered file ? Unordered file do no has any sequence although ordered file has arranged in a few sequence and data are assigned in ordered form

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

Create a subroutine, 1. Create a subroutine that does the remote blast on t...

1. Create a subroutine that does the remote blast on the file protein.fa. 2. Pass that returned files from the blast to another subroutine that parses the output and sends it to

Explain the term high level dml, Explain the term High level DML? High...

Explain the term High level DML? High level DML A high-level or non-procedural DML permit the user to specify what data is needed without specifying how it is to be acquired.

Compute natural join and outer join, For the relations R and S given below:...

For the relations R and S given below: R                      S A B C 1 4 7 2 5 8 3 6 9

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