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

Database for Managers, I have to create a database about anything of my cho...

I have to create a database about anything of my choice. It has to contain 4 queries, and 4 forms. It can be anything as simple as a shoe inventory with numbers - is this a service

Database, . Ashutosh Dubey who is the director of Gyan Gurukul want a three...

. Ashutosh Dubey who is the director of Gyan Gurukul want a three-level schema architecture for the Gyan Gurukul Company that provide better security also design a data abstraction

Why do you go for sorting your query results, Why do you go for sorting you...

Why do you go for sorting your query results? SQL SELECT command to fetch data from MySQL table. Whenever you select rows, the MySQL server is free to return them in any order

Explain network model in dbms, Explain Network Model in DBMS? Network ...

Explain Network Model in DBMS? Network Model - It was formalised within the late year of 1960s through the Database Task Group of the Conference on Data System Language (DBTG

What is use of generating such tables, What is use of generating such table...

What is use of generating such tables? How can you create temporary tables? When you require a table only for a short time after that you want it to disappear automatically you

Insert statement reverses storage space and transfers value, A field-groups...

A field-groups statement or an insert statement reverses storage space and transfers values. False.

Update anomaly-data redundancy, Update Anomaly : This anomaly is occurred d...

Update Anomaly : This anomaly is occurred due to data redundancy. Redundant information makes updates more complex since, for example, varying the name of the instructor of MCS-014

Design and building a distributed information system, prototype of a distri...

prototype of a distributed information system for a national car part retail outlet chain.

Describe physical data independence, Describe Physical Data independence ? ...

Describe Physical Data independence ? Physical Data Independence - It is capacity to modify the internal schema without having to change conceptual schema. Therefore, the exter

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