Super keys, Database Management System

Assignment Help:

A super key is an attribute or set of attributes used to recognize the records uniquely in a relation.

For instance, in the Relation PERSON defines earlier PERSON_ID is a super key since PERSON_ID is unique for every person. Likewise (PERSON_ID, AGE) and (PERSON_ID, NAME) are also super keys of the relation PERSON as their combination is also unique for each record.


Related Discussions:- Super keys

What is meant by object identifiers, What is meant by object identifiers? ...

What is meant by object identifiers? Object-oriented systems use an object identifier to recognize objects. Object identifiers are unique: that is every object has a single ide

Short note on mid square method of hashing, Short Note on mid Square Method...

Short Note on mid Square Method of hashing? Mid square method of hashing: In the method midsquare hashing, the key is squared and the address selected from the center of the s

What are the time stamps associated with each data item, What are the time ...

What are the time stamps associated with each data item? W-timestamp (Q) denotes the largest time stamp if any transaction that implemented WRITE (Q) successfully. R-timesta

Define cascading rollback, Define Cascading rollback The phenomenon whe...

Define Cascading rollback The phenomenon where a single transaction failure leads to a series of transaction rollbacks is known as Cascading rollback.

Modular growth, Modular growth: In distributed environments, it is simple t...

Modular growth: In distributed environments, it is simple to expand. Latest sites can be added to the network without affecting the operations of other sites, as they are somewhat

Serialisability, Serialisability: Any schedule that makes the similar resul...

Serialisability: Any schedule that makes the similar results as a serial schedule is known as a serialisable schedule. But how can a schedule are determined to be serialisable or n

Explain deadlock detection and recovery, Explain Deadlock detection and rec...

Explain Deadlock detection and recovery Deadlock Detection - A deadlock is said to take place when there is a circular chain of transaction, every waiting for the release of a

What is trigger, What is trigger?  Triggers are statements that are exe...

What is trigger?  Triggers are statements that are executed automatically by the system as the side effect of a modification to the database.

Relational model, A model in database system mostly defines the organisatio...

A model in database system mostly defines the organisation of data or structure and a set of operations on that data. Relational model is a easy model in which database is represen

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