Define query processing, Database Management System

Assignment Help:

Define Query Processing

Query processing is the process of selecting the best plan or strategy to be employed in responding to a database request. The plan is then executed to produce a response. The component of the DBMS accountable for generating this strategy is known as a query processor. It is a step by step process. The first or initial step is to transform the query into a standard from. For instance, a query in QBE   looked into by the research community.  Query might be transformed into a relational algebraic expression; the optimization is carried out by substituting equivalent expressions for those in the query. In the next step a number of strategies known as access pans are generated for evaluating the transformed query. The physical characteristics of the data and any supporting access method are taken into account in producing alternate access pans. The cost of each access plan is calculated and the optimal one is selected and executed.


Related Discussions:- Define query processing

Construct substantial data model, PART MARKING:  We will only mark TWO of t...

PART MARKING:  We will only mark TWO of the four questions below but you must submit answers to all four. We will choose the questions we mark randomly and we will supply you with

boyce codd normal form relations, Create centralized relational database u...

Create centralized relational database using bottom up method.   (a) Recognize a single un-normalized relation for the above scenario.          (b) Recognize the primary key for

Serialisability, Serialisability: Any schedule that makes the similar resul...

Serialisability: Any schedule that makes the similar results as a serial schedule is known as a serialisable schedule. But how can a schedule are determined to be serialisable or n

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

Explain nested relations, Explain nested relations? Nested relations ...

Explain nested relations? Nested relations The assumption of INF is a natural one in the bank examples we have considered. However, not all applications are best modelled

Database, Three way to handle missing field val

Three way to handle missing field val

Database incident table, The Incident table, with an auto-incrementing in...

The Incident table, with an auto-incrementing incident number, etc, looks like: incident_num reporter date time incide

Give an example of enforcement in typing, Give an example of enforcement in...

Give an example of enforcement in Typing. You can understand the idea of enforcement as it makes sure objects of dissimilar classes may not be interchanged as below:  Exampl

Explain b-tree, What is B-Tree? A B-tree eliminates the redundant stora...

What is B-Tree? A B-tree eliminates the redundant storage of search-key values .It permits search key values to appear only once.

Graphical user interface tools, These are interactive interfaces, graphical...

These are interactive interfaces, graphical that hide the difficulty of the DBMS and query language behind an intuitive, simple to understand, and convenient interface. This permit

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