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

E-r model uses this symbol to represent weak entity set, E-R model uses thi...

E-R model uses this symbol to represent weak entity set ? A Doubly outlined rectangle symbol is used to represent weak entity set.

What are the uses of the information in the data dictionary, What are the u...

What are the uses of the information in the Data dictionary? The following information is directly taken from the Data dictionary: Information on fields displayed with

State the technique for converting a state diagram to code, Q. State the Te...

Q. State the Technique for converting a state diagram to code. i) Identify the major control path. Starting with first state, find the path from diagram that corresponds

Indexed (indexed sequential) file organisation, Indexed (Indexed Sequential...

Indexed (Indexed Sequential) File Organisation It organises the file like a big dictionary, i.e., records are kept in order of the key but an index is stored which also allows

What is aggregate function, What is aggregate function? Briefly describe it...

What is aggregate function? Briefly describe it? Aggregate functions are functions that take a collection of values as input and return a one value. SQL offers 5 built-in aggre

Explain recovery process after system failure, Explain recovery process aft...

Explain recovery process after system failure using checkpoint. Ans: Checkpoint scheme or method is an extra component of the log based recovery system. This scheme is used to

What is deadlock, What is deadlock? How can it be avoided? How can it be re...

What is deadlock? How can it be avoided? How can it be resolved once it occurs? Deadlock happens when two transactions are each waiting on a resource that the other transaction

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

.DBMS, please describe the data base management with the easy example &giv...

please describe the data base management with the easy example &give the application?

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