How to rearrange classes and operations, Database Management System

Assignment Help:

Rearrange Classes and Operations

Sometimes, the similar operation is defined across different classes and can easily be inherited from a familiar ancestor, but more often operations in several classes are similar, but not the same. By slightly altering the definitions of operations or classes, the operations could often be made to match so that they could be covered by a single inherited operation. The following types of adjustments can be made to increase chance of inheritance:

  • We will find that some operations can have fewer arguments than others. The missing arguments can be added but normally ignored. Such as, a draw operation on a monochromatic display does not require a colour parameter, but parameter can be accepted and ignored for uniformity with colour displays.
  • Some operations can have fewer arguments since they are special cases of more common arguments. In this case, you can implement special operations by calling general operation with appropriate parameter values. Such as, appending an element to list is a special case of inserting an element; here the insert point just follows the last element.
  • Same attributes in different classes can have different names. Give attributes the same name and move them to a common ancestor class, then operations that access attributes will match better. Also, watch for same operations with different names. You should note that a reliable naming strategy is significant to avoid hiding similarities.
  • An operation can be defined on many different classes in a group, but be undefined on other classes. Define it on a common ancestor class and declare it as a no-op on classes which do not care about it. For instance, in OMTool the begin-edit operation places some figures, for example class boxes, in a special draw mode to authorize rapid resizing while the text in them is being edited. Other figures do not have special draw mode, so begin-edit operation on these classes has no effect.

 


Related Discussions:- How to rearrange classes and operations

Differentiate oo development from structured development., Differentiate OO...

Differentiate OO development from structured development. Structured approach of problem solving is based upon the idea of decomposition of system into subsystem. In this appro

RDM & ER Modelling, #questiRegional Gardens has many nurseries, including W...

#questiRegional Gardens has many nurseries, including Wagga Wagga, Bathurst, Albury, Orange, and Dubbo. Each nursery is known by its campus code, eg WW, B, A, O and D respectively.

Parallelism of transaction execution-data fragmentation, Parallelism of tra...

Parallelism of transaction execution: A transaction can be divided into various sub-queries that can operate on fragments in parallel. This enhances the degree of concurrency in t

Define mysql_fetch_object(), What are the differences among MySQL_fetch_arr...

What are the differences among MySQL_fetch_array(), MySQL_fetch_object(), MySQL_fetch_row()? Mysql_fetch_object returns the result from the database like objects while mysql

What is meant by physical blocks, What is meant by Physical blocks? The...

What is meant by Physical blocks? The input and output operations are completed in block units. The blocks residing on the disk are referred to as physical blocks.

Describe dynamic model, Describe Dynamic Model. The dynamic model speci...

Describe Dynamic Model. The dynamic model specifies allowable sequences of changes to the objects from an object model. It contains event trace diagrams describing scenarios. A

Explain about database system structure, Explain about database system stru...

Explain about database system structure? Storage manager Authorization and integrity manager Transaction manager File manager Buffer manager Storage manager

File organization, what is file organization? what are file organization te...

what is file organization? what are file organization techniques.explain in detail? explain random file organization technique, multikey file organization technique?what is indexin

Explain naivebayessimple algorithem, Use the IRIS dataset that comes with W...

Use the IRIS dataset that comes with Weka to compare the classification performance of the following algorithms. 1. NaiveBayesSimple 2. MultiLayerPerceptron J48 (

What is recovery management component, What is recovery management componen...

What is recovery management component? Ensuring durability is the responsibility of a software component of the base system known as the recovery management component.

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