Binary relationships, Database Management System

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

 

 

 

 

 

 

 

 

Posted Date: 3/6/2013 6:26:41 AM | Location : United States







Related Discussions:- Binary relationships, Assignment Help, Ask Question on Binary relationships, Get Answer, Expert's Help, Binary relationships Discussions

Write discussion on Binary relationships
Your posts are moderated
Related Questions
What is meant by object identifiers? Object-oriented systems use an object identifier to recognize objects. Object identifiers are unique: that is every object has a single ide

Describe the primary key functions? Primary Key : The primary key is an attribute or a set of attributes in which uniquely identify a specific example of an entity. Every entit

Database Management Systems 1. Explain SQL Server 2000 Architecture with diagram. 2. Describe Second Normal and Third Normal Form. 3. Explain about query engine and stora

Consider the following relational database: STUDENT (name, student#, class, major) COURSE (course name, course#, credit hours, department) SECTION (section identifier, course#, sem

what do you mean by consistency in rdbms?

(a) Design a query plan for the following distributed query: An application at site B wants to compute a join of STUDENT ? Id=StudId TRANSCRIPT where STUDENT (Id,Major) is at site

A buyer for a large department store chain must place orders with an athletic shoe manufacturer six months prior to the time the shoes will be sold in the department stores. In par

#question. Draw a picture of a moving source and the waves surrounding it according to what you observed in this experiment. How does the spacing of the wave-fronts in front of the


XYZ is a large chain of home entertainment rental over 100 stores distributed over all states in Australia. XYZ lends entertainment products such as movies, TV shows and games on v