Relation instance or relation state, Database Management System

Assignment Help:

A relation instance indicates as r is a collection of tuples for a given relational schema at a exact point of time.

A relation state r of the relation schema R (A1,A2,..........AN), also denoted by r(R) is a set of n-tuples

r = {t1,t2,............tm}

Where each n-tuple is an ordered list of n values

t  =  1,v2,........, vn>

where every vi belongs to domain (Ai) or includes null values.

The relation schema is also known as  'intension' and relation state is also known as 'Extension'.


Related Discussions:- Relation instance or relation state

Distributed query and transaction processing, a.  Construct a query around ...

a.  Construct a query around any one of the functional divisions you made in 4a such that if executed in the distributed design of 4 would require reconstruction of at least two ho

Database ass1, #quCreate a database design specification (Enhanced Entity R...

#quCreate a database design specification (Enhanced Entity Relationship Diagram (EERD) and Relational Data Model (RDM)) from the given business description. The RDM must be in 3rd

What are the two main goals of parallelism, What are the two main goals of ...

What are the two main goals of parallelism? Load -balance multiple small accesses, so that the  throughput of such accesses enhances. Parallelize large accesses so that the res

Get details of employee working on both comp354 and comp345, Consider the r...

Consider the relations EMPLOYEE(emp#, name) ASSIGNED_TO(project#, emp#) PROJECT(project#, project_name, chief) Express the subsequent queries in Relational Algebra (i) Ge

HIT, Meaningful use refers to the use of certified EHR technology to "enhan...

Meaningful use refers to the use of certified EHR technology to "enhance quality, efficiency, and reduce health disparities

Define blocks, Define blocks? The database system resides eternally on ...

Define blocks? The database system resides eternally on non-volatile storage, and is into fixed-length storage units known as blocks.

Why were functional methods fashionable in early days, Why were functional ...

Why were functional methods fashionable in early days? These are inspired directly by computer architecture and thus popular among computer scientist in early days. The divisio

What are decision support systems, Question: (a) What are decision sup...

Question: (a) What are decision support systems, and what role do they play in the business environment? (b) Data mining is a knowledge discovery process of automated extr

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