bsys 2060 lecture 4, april 12 th

BSYS 2060Lecture 4, April 12th

Midterm overviewNormalization

Agenda

• External events• Announcements• Midterm format• Course questions• Normalization• Bank database exercise• Team project

http://www.vef.org/

http://www.newventuresbc.com/the-competition/about-the-competition/

Announcements

• If you miss labs because of Easter stat holidays, you need to do the lab exercise outside of regular lab time

• If you miss your Friday lab because of Open House, you can go to one of the other lab slots

Midterm Format: Free range – open book, open Internet… the only un-natural part is you can’t collaborate.

Image source: “truly free range chickens” by Brookford Farm, CC BY 2.0

50% - Multiple Choice, 25 questions worth 2 each50% - Data Modeling question, 1 page

Held during your Week 5 lab

You are writing the questions…

• Each student in their Week 4 lab needs to come up with a multiple choice question

• Question topics assigned by set• Use local context where applicable in your

questions• Use images where applicable• Sample question process

* At least some of them

*

https://zenportfolios.ca/groups/bsys-2060-2012/forum/

https://zenportfolios.ca/bcit-bsys-2060-2012/midterm-question-submission/

Source: http://www.flickr.com/photos/caius/2300154566/

Normalization…

In relational database design, the process of organizing data to minimize redundancy.

Normalization defined:

Source: http://www.webopedia.com/TERM/N/normalization.html

Normalization usually involves dividing a database into two or more tables and defining relationships between the tables.

Why bother?

Source: http://www.webopedia.com/TERM/N/normalization.html

The objective is to isolate data so that additions, deletions, and modifications of a field can be made in just one table and then propagated through the rest of the database via the defined relationships.

Why bother?

Source: http://www.webopedia.com/TERM/N/normalization.html

1. Atomicity & uniqueness… No repeating elements or groups of elements and each row of data must have a unique identifier (i.e. primary key)

First normal form

2. No partial dependencies on a concatenated key

Second normal form

3. No dependencies on non-key attributes

Third normal form

An example… orders

1. Atomicity & uniqueness… No repeating elements or groups of elements and each row of data must have a unique identifier (i.e. primary key)

First normal form

So far, it doesn’t meet criteria for 1NF

2. No partial dependencies on a concatenated key

Second normal form

Summary