What are the general transformation rules, Database Management System

Assignment Help:

What are the General Transformation Rules for Relational operations? 

Ans: The transformation rules transform one relational algebra expression to AN

EQUIVALENT ONE 

1. Employed by the query optimizer to optimize query tree 

2. Any type of rule, if applied, ensures that the resultant tree is equivalent → resulting execution plan is equivalent 

 General Transformation Rules is as follow:

1. Commutativity of s: The s operation is commutative: 

  • sc1 (sc2(R)) = sc2 (sc1(R))
  • More selective selections first

Related Discussions:- What are the general transformation rules

Difference between left outer join and right outer join, Difference between...

Difference between LEFT OUTER JOIN and RIGHT OUTER JOIN In left outer join tuples from the left-hand-side relation which do not match any tuple in the right-hand-side relation

Describe the different raid levels, Describe the different RAID levels.  Di...

Describe the different RAID levels.  Discuss the choices of the different RAID levels for different applications.          Ans:   There are several combinations of these approa

Implementing a distributed database system, A distributed database is defin...

A distributed database is defined as "a collection of multiple logically interrelated database which are physically distributed over a computer network" (a) Give any three advan

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

Database part of ldb?, Is it mandatory to declare all the tables in Report ...

Is it mandatory to declare all the tables in Report by the key word tables for all the tables that exist in the structure of LDB, and are being explained in the Database part of LD

Mapping, external and internal mapping with examples

external and internal mapping with examples

Spanned and unspanned organisation, Spanned and unspanned organisation? ...

Spanned and unspanned organisation? Spanned and unspanned organization: If records are not permited to cross block boundaries then the organisation is called unspanned record

What does the cardinality ratio specify, What does the cardinality ratio sp...

What does the cardinality ratio specify? Mapping cardinalities or cardinality ratios state the number of entities to which another entity can be associated. Mapping cardinaliti

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