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

What is the candidate key for a table with columns, For problems 1-4, give ...

For problems 1-4, give all candidate keys for the tables with FDs specified.  Composite candidate keys must be put in parentheses, and candidate keys must be separated with commas

What are multiple inheritances, What are multiple inheritances? Multipl...

What are multiple inheritances? Multiple inheritances allow a class to inherit variables and methods from many super classes.

Clinic, Need a sample of a clinic database relationships

Need a sample of a clinic database relationships

State the two-way associations, Two-way Associations Mostly, associati...

Two-way Associations Mostly, associations are travel in both directions, although not usually with same frequency. There are three approaches for the implementation. In

Normalization, Introduction In large projects, we can have many different ...

Introduction In large projects, we can have many different companies working together. Generally, the project or contract is awarded to one company (Principal Contractor), which

Structure of the ldb, Though all the ABAP/4 Dictionary Structures that exis...

Though all the ABAP/4 Dictionary Structures that exists in the structure of the LDB, being described in Database Program, we are explaining the Dictionary Structures in the Report.

Normalization, in case of functional dependencies how we get the higher nor...

in case of functional dependencies how we get the higher normal form.

What is the use of group by clause, What is the use of group by clause?  ...

What is the use of group by clause?  Group  by  clause  is  used to apply  aggregate  functions  to a  set  of  tuples. The attributes given in the group by clause are used to

What is dml (data manipulation language)?, This language that enable user m...

This language that enable user manipulate to or access data as organized by appropriate data model. Low level or Procedural DML : DML needs a user to specify what data ar

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