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

Define the terms ddl and dml, Define the terms i) DDL ii) DML DDL: Data...

Define the terms i) DDL ii) DML DDL: Data base schema is particular by a set of definitions expressed by a special language known as a data definition language. DML: A data

Assignment, how does Btree differ from a B+ - tree?

how does Btree differ from a B+ - tree?

Explain projection operation distribute over union operation, Illustrate th...

Illustrate the statement 'Projection operation distributes over the union operation'. Give an example.    Ans: Π L (E 1 ∪ E 2 ) = (Π L (E 1 )) ∪ (Π L (E 2 ))   This says th

What is the use of integrity constraints, What is the use of integrity cons...

What is the use of integrity constraints? Integrity constraints make sure that changes made to the database by authorized users do not result in a loss of data consistency. The

What is enterprise resource planning, What is Enterprise Resource Planning ...

What is Enterprise Resource Planning (ERP), and what kind of a database is used in an ERP application? Enterprise Resource Planning (ERP) is an information system used in manuf

Approach to implement traffic data management, There are many simple and co...

There are many simple and complex approaches to implement. These reports are based on some views or certain query. The following number of reports can be built. 1. The averag

Need senior oracle database administrator, Project Description: Oracle C...

Project Description: Oracle Certified Professional with 20 years of practice, Oracle version 6.0.34, 7.3, 8.0, 8i, 9i, 10G, 11G, 12C. Crossplatform migration, Informix, MSSql

Sparse and dense indexes, Sparse and Dense Indexes These indexes in pri...

Sparse and Dense Indexes These indexes in principle are the similar as that of indexes used at the back of the book. The key facts of the indexes are: They are arranged

What you understand by client-server environment, Problem: a) Briefly d...

Problem: a) Briefly describe what you understand by Client-Server environment b) The File Server is a simple form of Client-Server. Describe the principles of the File Serve

In a hierarchical model of data records are organized, In a Hierarchical mo...

In a Hierarchical model of data records are organized ? In the hierarchical model of data records are organized as Tree structure.

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