One-to-many relationship, Database Management System

For each 1: n relationship type R involving two entities E1 and E2, we recognize the entity type (say E1) at the n-side of the relationship type R and contain primary key of the entity on the other side of the relation (say E2) as a foreign key attribute in the table of E1. We contain all easy attributes (or easy components of a composite attributes of R (if any) in the table of E1).

For example, the works_in relationship among the DEPARTMENT and FACULTY.

For this relationship choose the entity at N side, i.e., FACULTY and add primary key attribute of one more entity DEPARTMENT, i.e., DNO as a foreign key attribute in FACULTY.

FACULTY (CONTAINS WORKS_IN RELATIONSHIP

ID

NAME

ADDRESS

BASIC_SAL

DNO

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Posted Date: 3/6/2013 6:27:08 AM | Location : United States







Related Discussions:- One-to-many relationship, Assignment Help, Ask Question on One-to-many relationship, Get Answer, Expert's Help, One-to-many relationship Discussions

Write discussion on One-to-many relationship
Your posts are moderated
Related Questions
What is a cascading update? Referential integrity constraints needs that foreign key values in one table correspond to primary key values in another. If the value of the primar

Describe integrity constraints? Integrity Constraints - A database is just as excellent as the information stored in it, and a DBMS must therefore help avoid the entry of inc

Which is another name for weak entity? Child is another name of weak entity.

Physical Records These are the records that are stored in the secondary storage devices. For the database relation, physical records are the group of fields kept in adjacent me

10A.53 Code an Oracle Database trigger to enforce the constraint that an employee can never change his or her department. 10A.54 Code an Oracle Database trigger to allow the

Farmer Bob, Farmer Jane and Farmer Jose run a cow farming co-op. For every cow they keep the cow’s name, age (or date of birth), breed and numbered plastic ear tag. The each of t


Lossless-Join Decomposition   Let us show an intuitive decomposition of a relation. We require a better basis for deciding decompositions since intuition may not always be r

Attribute Preservation This is a easy and obvious necessity that includes preserving all the attributes that were there in the relation that is being decomposed.

Consider a relation s over the attributes A and B with the following characteristics: 5,000 tuples with 10 tuples per page A 2-level B+ tree index on attribute