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

Develop c# schoolproject asap, Develop C# schoolproject ASAP Helping me ...

Develop C# schoolproject ASAP Helping me with schoolproject. The project is prepared in C# and haves a database connection. We have some small issues asking up data from t

What is data model explain object and data base models, What is data model?...

What is data model? Explain object based and record based data models? Ans: A data model is an abstract model in which describes how data is represented and accessed. (i)

Query evolution, what is query processing ,query optimization and performan...

what is query processing ,query optimization and performance turring?

What features relational dbms contribute level of integrity, A well-maintai...

A well-maintained relational DBMS has a high level of data integrity. What features of a relational DBMS contribute towards this level of integrity? Relational DBMS gives high

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

What is identity, What is Identity? Identity (or AutoNumber) is a colum...

What is Identity? Identity (or AutoNumber) is a column that automatically produces numeric values. A start and increment value can be set, but most DBA leave these at 1. A GUID

Advantages and disadvantages of using a database system, What are the advan...

What are the advantages and disadvantages of using a database system. Sol. Advantages of Database System (DBMS) :  (1) Data Redundancy and Inconsistency: Since differen

Cases of constraint violations, (1)     Insert into PERSON Violated con...

(1)     Insert into PERSON Violated constraint: - Key constraint Reason: - Primary key 1 already exists in PERSON. Dealing: - DBMS could ask the user to provide valid PER

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