Erd exercise 2 l.jpg
Advertisement
This presentation is the property of its rightful owner.
1 / 11

ERD Exercise #2 PowerPoint PPT Presentation

ERD Exercise #2 CIS458 Organizational Database Management Identify all the entities. Identify all the relationships. Identify cardinality and multiplicities (min max). Creating an ERD from the Investigated Facts (1..*) (0..1) (0..*) (1..1) Simple ERD 1

Download Presentation

ERD Exercise #2

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Erd exercise 2 l.jpg

ERD Exercise #2

CIS458

Organizational Database Management


Creating an erd from the investigated facts l.jpg

Identify all the entities.

Identify all the relationships.

Identify cardinality and multiplicities (min max).

Creating an ERD from the Investigated Facts

(1..*) (0..1) (0..*) (1..1)


Simple erd 1 l.jpg

Simple ERD 1

  • A painter can paint many paintings; each paining is painted by one painter. A gallery can have many paintings. A painting can be exhibited by a gallery.

Paint ►

(0..*)

Displayed

(1..1)

Painter

(1,1)

(0..*)

Painting

Gallery


Simple erd 2 l.jpg

Simple ERD 2

  • An employee can learn many skills; each skill can be learned by many employees.

  • Expert Level? (L1.. L5)

Learn ►

(0..*)

(0..*)

Employee

Skills

Expert Level


Simple erd 3 l.jpg

Simple ERD 3

  • An employee manages one store; each store is managed by one employee

Employee

Store

Manages ►

(0..1)

(1..1)

Employee

Store


Simple erd 4 l.jpg

Simple ERD 4

  • A College example

  • Students in a typical college or university will discover that each course can have many sections or no section, by each section refers to only one course.

  • For example, an Accounting II course might have two sections: one offered on Monday, Wednesday, and Friday from 10:00 a.m. to 10:50 a.m., and one offered on Thursday from 6:00 p.m. to 8:40 p.m.


Slide7 l.jpg

Has ►

(1..1)

(0..*)

Course

Section


Simple erd 5 l.jpg

Simple ERD 5

  • Each student can take many classes (or no class at all) and each class can contain many students.

  • Add Grade

Take ►

(1..*)

(0..*)

Student

Classes

Grade


Combining erds l.jpg

Combining ERDs

  • A class can be identified with course and section.

Has ►

(1..1)

(0..*)

Course

Section

Take ►

(1..*)

(0..*)

Student

Section


Slide10 l.jpg

Has ►

(1..1)

(0..*)

Course

Section

(0..*)

Take▼

(1..*)

Student


Adding additional conditions l.jpg

Adding Additional Conditions

  • Adding prerequisite, enroll grade

Has ►

(1..1)

(0..*)

Course

Section

(0..*)

(0..*)

(0..*)

Take ▼

Grade

◄Prerequisite

(1..*)

Student


  • Login