1. Data Design
Making sense of SQL.

2. Database Design Principles.

3. Database Design Principles.
Know your technology and it’s limits.

4. Database Design Principles.
Know your technology and it’s limits.
Collect all relevant information regarding
your project’s data and plan, plan, plan.

5. Database Design Principles.
Know your technology and it’s limits.
Collect all relevant information regarding
your project’s data and plan, plan, plan.
Only approach the computer once you
have mapped out your database on paper.

6. The technology
Certain databases have limits, so know them.
Microsoft Access 2 gigabyte
Operating System sets the
Microsoft SQL Server
limit.
Operating System sets the
My SQL
limit.

7. The technology
Databases can have a limit to the number of
concurrent connections.
Microsoft Access 255 users
Microsoft SQL Server unlimited
125 by default
My SQL
unlimited once configured.

8. The technology
Databases have costs associated to them.
Microsoft Access Can$300.00
Microsoft SQL Server $700 - $30 000 +
My SQL free

9. The technology
Since the database is software, we have to
ensure that we have powerful enough
hardware to meet the demand of the service.
Lots of users asking for data = Lots of power.

11. Google Data Centre

12. The technology
Don’t paint yourself into a corner because of
bad technology choices. Imagine the worst
case scenario and PLAN FOR IT!
MySQL can grow as long as there is hard
drive space to handle the data files and
servers fast enough to manage the traffic.

13. Planning Your Database
• Understand the data that you will be
creating in the database and design entities.
• An entity is a collection of objects
(persons, places, things) described by the
same attributes.
• Entities are identified during the
conceptual design phase of database and
application design.

14. Planning Your Database
• Often the term entity is used instead of
the word table.
• A table in a database is where attributes
are stored.
• Attributes can be numbers, words, dates
and even binary data objects. These are
called the “data type” and are set on each
attribute in the table.

15. TABLE (or entity):
tbl_myFriendsBirthdays
Attribute Data Type Sample Data
id integer 2
Name string Joe
Birthday date/time 4082008
This table will store my friend’s birthdays. All of my
friends have a name and a date of birth, so those ideas
will become attributes.
The complete collection of my friends attributes will
become records in this table.

16. Planning Your Database
• Understand all of the data entities that you
would ever want to store in the database.
• Attempt to consider all available options
and variations that your application is going
to require.

17. Exercise
Let us pretend we are being asked to create
an inventory database for a shoe company
that manufactures different styles of
footwear for different brands, like Nike.
Let’s create a list of all related data that we
would need to store regarding their
inventory.

18. Homework
• Discover all of the data types that can be
applied to attributes of a table (entity).
• Print them onto a sheet of paper and bring
this to next class. Please no copy and paste
and have your name and the date on the
sheet.