Binary relationships, Database Management System

Assignment Help:

One-to-one relationship:

For every 1:1 relationship type R in the ER diagram including two entities E1 and E2 we take one of entities (say E1) preferably with total participation and add primary key attribute of one more entity E2 as a foreign key attribute in the table of entity (E1). We will also have all the simple attributes of relationship type R in E1 if any.

For instance, the DEPARTMENT relationship has been extended to contain head-Id and attribute of the relationship. Please note we will maintain information in this table of only present head and Date from which s/he is the head.

There is one Head_of 1:1 relationship among FACULTY and DEPARTMENT. We select DEPARTMENT entity having total participation and add primary key attribute ID of FACULTY entity as a foreign key in DEPARTMENT entity named as Head_ID. Now the DEPARTMENT table will be as follows:

DEPARTMENT

D_NO

D_NAME

Head_ID

Date-from

 

 

 

 

 

 

 

 


Related Discussions:- Binary relationships

Explain current page table and shadow page table, Explain current page tabl...

Explain current page table and shadow page table. The key idea behind the shadow paging method is to maintain two page tables during the life of the transaction: the current pa

What is serializability, What is serializability? Explain its types? Th...

What is serializability? Explain its types? The data base system must control concurrent implementation of transactions, to ensure that the data base state remains consistent.

Explain disadvantages of a dbms, Question : (a) Database Management Sy...

Question : (a) Database Management Systems (DBMS) is the foundation of business intelligence. Explain the following concepts related to DBMS: (i) Entity Relationship Diagr

Delete - referential integrity, During the deletion of a tuple two cases ca...

During the deletion of a tuple two cases can happen: Deletion of tuple in relation having the foreign key: In this type of case simply delete the desired tuple. For example, in

Explain the term- inheritance, What is inheritance? Inheritance is an ...

What is inheritance? Inheritance is an object orientation concept that allows reusability of code / design. Basic sense of inheritance is that if one class is predefined than a

Types of attributes, Attributes attached to an entity can be of various typ...

Attributes attached to an entity can be of various types. Simple The attribute that cannot be further separated into smaller parts and shows the basic meaning is known as a

How to rearrange classes and operations, Rearrange Classes and Operations ...

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 oper

OLD HOME POLICIES, Write an sql statement to find what is the percentage of...

Write an sql statement to find what is the percentage of home policies which are from the state of Arizona out of all Home policies by Policy Value.

Define the terms entity, Define the terms entity, attribute, role and relat...

Define the terms entity, attribute, role and relationship between the entities, giving examples for each of them.         Ans: Entity:   An entity is a "thing" or "object" in th

Write short note on events, Write short note on Events Events consist ...

Write short note on Events Events consist of inputs, interrupts, decisions and actions performed by any external device or users. Every event always has a sender and receiver.

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