[Year 12 IT Apps] Entity-Relationship Diagram - Unit 3 Outcome 2

[Peter Langham]

Mark, what I beleive you are referring to is a Data Structure Diagram (see
Figure 3-29 on page 109 of our Textbook) I am referring to
Entity-Relationship Diagrams (see Figure 3-27 on page 107 of our Textbook).

They appear to have a similar purpose, although they are quite different in
appearance.

On Thu, Mar 31, 2011 at 8:22 AM, Mark KELLY <kel at mckinnonsc.vic.edu.au>wrote:

> Hi Peter
> When I think of ERDs for databases, I'm seeing a picture of the database's
> tables with their related key fields connected by relationship lines. These
> lines usually have "1" on one end and a "many" symbol on the other...
>
> Are we thinking of the same thing?
>
>   On 30 March 2011 16:54, Peter Langham <peterlangham1983 at gmail.com>wrote:
>
>>   Hi guys,
>>
>> I'm looking for some clarification on Entity-Relationship Diagrams.
>>
>> I'm planning to develop a pet shop database as that will have a Customers
>> Table, Products Table and Orders Table.
>>
>> When I complete my entity-relationship diagram I will use Customers,
>> Products and Orders (or Invoices) as my entities.
>>
>> But I'm unsure if I'm doing the Relationships correctly.
>>
>> Customer - BUYS - Product
>> Customer - PAYS - Order (or Invoice)
>> Order (or Invoice) - Displays/Outputs - Product (Information)
>>
>> Is this correct?
>>
>> Thanks for your time.
>>
>> Peter Langham.
>> Narre Warren South P-12.
>>
>> _
>>
>
> --
> Mark Kelly
> Manager of ICT, Reporting, IT Learning Area
> McKinnon Secondary College
> McKinnon Rd McKinnon 3204, Victoria, Australia
> Direct line / Voicemail: +613 8520 9085, Fax +613 9578 9253
> kel at mckinnonsc.vic.edu.au
> VCE IT Lecture Notes: http://vceit.com
> Moderator: IT Applications Edulist
> All generalisations are false, except this one.
>
>
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