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

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

What is a virtual table that draws its data from the result, What is a virt...

What is a virtual table that draws its data from the result of an SQL SELECT statement? View is a virtual table that draws its data from the result of an SQL SELECT statement.

What subschema expresses, What subschema expresses ? A subschema expres...

What subschema expresses ? A subschema expresses the external view. (External schemas are called also called as subschemas)

Create a query to produce single output-er model, This assignment concerns ...

This assignment concerns the Research database. The database ER model is shown above, where attributes are omitted for clarity. The relational model for the database is: Departm

What is deadlock, What is deadlock? Neither of the transaction can ever...

What is deadlock? Neither of the transaction can ever proceed with its normal implementation. This situation is known as deadlock.

Database, real life situations where database management system are most su...

real life situations where database management system are most suitable

Queries, Find the names of all Albums that have more than 30 tracks. Result...

Find the names of all Albums that have more than 30 tracks. Result: (name: varchar(255))

What is outer join, What is Outer join?  They can be employed while we ...

What is Outer join?  They can be employed while we want to keep all the tuples in R, or all those in S or all those in both relations in the result of the JOIN in spite of of w

Define instance and schema, Define instance and schema? Instance: Colle...

Define instance and schema? Instance: Collection of data stored in the data base at a certain moment is Schema: The overall design of the data base is known as the data base

What type of view of total database content, What type of view of total dat...

What type of view of total database content? Data base content Conceptual view of total database contain.

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