What is completeness constraint on generalization, Database Management System

Assignment Help:

What is completeness constraint on generalization? Define the variation between total and partial design constraint. Give an example each.    

 Ans: Completeness Constraints 

1. Total specialization  constraint

a. Each entity in the superclass should be a member of some subclass in the specialization for example {HOURLY_EMPLOYEE, SALARIED_EMPLOYEE} 

b. Notation: superclass 

2. Partial specialization constraint an entity might not belong to any type of the subclasses 

For example: {SECRETARY, ENGINEER, TECHNICIAN}


Related Discussions:- What is completeness constraint on generalization

What is primary key, What is Primary key? Primary Key - Primary key i...

What is Primary key? Primary Key - Primary key is one of the candidate keys which uniquely identifies each row in the relation.

What is specialization, What is Specialization? Specialization: Special...

What is Specialization? Specialization: Specialization permits you to describe new types of information (new structural types or latest domains of information), although reusin

Define the terms entity type and entity set, Define the terms i) Entity typ...

Define the terms i) Entity type ii) Entity set Entity type: An entity type describes a collection of entities that have the similar attributes. Entity set: The set of all en

Define the term database, QUESTION (a)(i) Define the term database. ...

QUESTION (a)(i) Define the term database. (ii) How is it different from a database management system? (b) What is the difference between an entity and an attribute? (c

What are the physical characteristics of magnetic disks, What are the physi...

What are the physical characteristics of magnetic disks?   Ans: A magnetic disk is a circular plate or platter of plastic or metal that is coated with magnetizable material lik

DW, #ques Define a job scheduling strategy that will meet business requirem...

#ques Define a job scheduling strategy that will meet business requirement of reporting availability by 6am CST for the following cubes? Show the job scheduling dependencies in a p

What is substitutability, What is substitutability? Any method of a cla...

What is substitutability? Any method of a class-say A can equally well be adjured with any object belonging to any subclasses B of A. This characteristic leads to code reuse, a

What are the dbms languages, What are the DBMS languages? Briefly explain?...

What are the DBMS languages? Briefly explain? Data Definition language (DDL):A database schema is specified through a set of definitions expressed through a special language

Multi-list file organisation, Multi-list file Organisation Multi-list f...

Multi-list file Organisation Multi-list file organisation is a multi-index linked file organisation. A linked file organisation is a logical organisation where physical orderin

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