1. Basic Database Design
COSC 2328 – Web Programming

2. The Design Process Determine the purpose of the database
Organize the information / divide the information into tables
Turn information into columns
Specify primary keys
Setup table relationships
Apply normalization rules

3. What is “Normalization”
Organizing the columns (attributes) and tables (relations) of a relational database
Why?
Reduce data redundancy
Reduce storage requirements
Improve data dependencies

4. 3 Normal Forms No repeating elements or groups of elements
No partial dependencies on a concatenated key
No dependencies on non-key attributes

5. Invoices

6. Tracking In A Spreadsheet
How many 56” Blue Freens were sold in 2002?
What was the total sales of 3” Red Freens came from Washington DC in 2016?

7. Filling In The Data
Oops – Now we have repeating elements

8. Creating A Composite Key
If we identify a primary key as the Invoice Number and Item ID, we get a unique key. There is no single column that identifies each row, but if we put the two columns together we now have a unique key.

9. No Partial Dependencies
Each column in the table that is not part of the primary key must depend on the entire concatenated key
If any column only depends on one part of the key, then we say that the entire table fails second normal form
Steps -- Take each column not part of the key. Can this column exist without one or the other part of the primary key? If ‘yes’ – even once – then the table fails Second Normal Form

10. Table Concepts
Break-up the spreadsheet into multiple tables in a database
Think about one-to-many and many-to-one relationships
Determine which fields belong to which tables
Use IDs to identify rows when necessary

11. Designing The Tables orders --------------------- orderId (PK)
customerId (FK)
orderDate
orderItems
orderId (PK) (FK)
itemId (PK) (FK)
itemQuantity
items
itemId (PK)
itemDescription
itemPrice 1 n n 1 n 1
customers
customerId (PK)
customerName
customerAddress
customerCity
customerState