Hi Guys,

I am working on a project and need some help on ER digrams... I am completely new to it and its kind of mind blowing.

Does anyone have any hints or can help me with this?

Cheers, Ramtin

For what kind of data? I don't know if it will help too much in your efforts, but I have lot's of vector clipart that can make clear your ideas...Color & Black & White Vector clipart. See my signature site.

The way we used to do it in uni was to write out the spec as a paragraph. Then highlight noun phrases (which will, generally, become the entities), verb phrases (which will generally be the relationships between them). And decide the normality (not sure if that is the correct term :S) between them i.e. many to many, 1 to many, many to 1.

e.g.

"The database should keep track of players who are members of each team and the matches that they play in."

Entities: Players, Teams, Matches

Relationships:

Players - member of - Team (M:1)
Players - play in - matches (M:M)

Hi Stuart,
Thanks heaps for your message... I am actually doing what you told me...

Here is the business rules that I need to based my model on:

• A student is identified by a unique student identification number
• A student is enrolled in only one course
• A student has a status which is Current, Deferred or Withdrawn
• A particular unit is offered by only one course
• A course must offer at least one unit
• A student may be enrolled in many units or none, depending on his/her status
• A unit must have students in it to run
• Every unit offers at least one tutorial
• A student may be enrolled in many tutorials or none, depending on his/her status
• A tutorial must have students in it to run
• Each tutorial is identified by a unique identification number
• Each tutorial is held in an allocated room, on a designated day and time each week
• A student with a Current status must attend a tutorial

You think you can help me more with this?

Cheers mate, Ramtin

Originally Posted by ramtinworld

I am working on a project and need some help on ER digrams... I am completely new to it and its kind of mind blowing.

Use the diagramming tool in SQL Server. You can do that, get it wrong, start over, as many times as you need. And once you start working with it, hands on, it stops being new and mind blowing, and becomes easy. You'll get the hang of it, but writing a bullet list won't make it less abstract - just jump in and do it.

for eg.

student(ID_No, Name, Address, etc..)

just draw the diagram, using the multiplicity they have...

_________
| student |
¯¯¯¯¯¯¯¯¯
| ID_No |
| Name |
| Address |
¯¯¯¯¯¯¯¯¯