Tutorial on Database Schema - Slide 4 - Enter Starbucks
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- Enter Starbucks
- Starbucks offers Products
- Customers can Order, for example, Coffee and Something to Eat
Our motto - Keep It Simple and Straightforward (KISS)
We are starting in a simple way with this diagram which shows two Entities without a Relationship.
The Relationship between them is established in the next diagram, when the meaning of the 'PK' and 'FK' will be explained.
I want to convey to you the value of seeing the real world as a Database Schema.
It's always very interesting and adds a challenge as you walk or drive around and
think about how you would create a Database Schema for the real world that you can see around you.
Let's say we go into Starbucks to get a coffee and something to eat.
At this point, Starbucks doesn't know us as a Customer.
Also we might be doing the office coffee run, amd maybe we have with us our Order on a piece of paper.
These two 'Things of Interest', Products and Customer_Orders, are not related until we give our Order.
Data Modellers commonly describe a Database Schema as an Entity-Relationship-Diagram, or ERD.
The word 'Relationship' is therefore very important.
However, at this point, we haven't established a Relationship between the Products and the Customer_Orders.
We will do that in the next slide.
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