The Second Lab
ER Diagram
(I) Connect to CS Server
Linux :
Mac :
Windows :
* You may also connect to csa3 instead of csa2 .
(II) Submit a Text File to gsubmit System
After logon to csa2 or csa3 server:
* Graduate students use cs660 instead of cs460 .
(III) Entity Relationship Model
(1) Entity Relationship Model: (2) Entity: (3) Relationship: (4) Mapping: (5) Key: (6) Special Cases: (7) ER Diagram: (7) Draw ER Diagram:
An abstract conceptual data model used in software engineering to represent structured data.
More references can be found here
An entity is a real-world thing.
An entity has attributes.
A relationship connects two or more entities.
A relationship can also have attributes.
One-to-One Mapping.
Many-to-One Mapping.
One-to-Many Mapping.
Many-to-Many Mapping.
Primary Key.
Super Key.
Foreign Key.
Candidate Key.
Weak Entity
Total Participation
Remember the symbols
Windows : Microsoft Office - PowerPonit or Visio
(1) Insert Shapes; (2) Export as JPG or PNG
Linux : LibreOffice - Draw
(1) Basic Shapes; (2) Export as JPG or PNG
Mac : Keynote
(1) Insert Shapes; (2) Export images as JPG or PNG
Web : Online ER Diagram Drawer
(IV) ER Diagram Example
Teams, Players and Plays
(1) Player (Entity): (2) Team (Entity): (3) Play (Relationship): (4) Player - Team (Relationship): (5) ER Diagram:
Each player has a name, a date of birth and a position.
Each team has a name and a location.
Each play has a date, a time and a result.
Each play connects exactly two teams.
Each player can only belong to one team; Each team may have multiple players