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

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

Er model, explain the steps for reduction of er model into relational model...

explain the steps for reduction of er model into relational model?

#title using the invoice, using the invoice table shown below,write the rel...

using the invoice table shown below,write the relational schema,draw a dependencies,inclunding all partial and transitive dependencies.assume that the table does not contain repeat

Update operations in dbms - insert operation, Update Operations and Dealing...

Update Operations and Dealing with Constraint Violations There are three basic operations to be executes on relations: Insertion Deletion Update The INSER

Search the salary of employees who are not ‘analyst’ , Example- Search the ...

Example- Search the salary of employees who are not 'ANALYST' but get a salary below than or equal to any people employed as 'ANALYST'. SELECT EMPNO, ENAME, JOB, SAL FROMEMP

Query optimization in database system, Problem : AirwaysCentre, an inte...

Problem : AirwaysCentre, an international airline booking company currently uses a relational database system for their operations, which includes the following relations: P

What does data dictionary is a special file contains, What does data dictio...

What does data dictionary is a special file contains ? The data dictionary is a special file contain The name of all fields in all files.The width of all fields in all files an

What is icr, What is ICR? A. ICR (Intelligent Character Recognition) is...

What is ICR? A. ICR (Intelligent Character Recognition) is a technology that gives scanning and imaging systems the ability to identify images of hand-printed or script charact

Define a property that is not a property of transactions, Define a property...

Define a property that is not a property of transactions? Ans: Concurrency is not a property of transactions

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