Lecture2 slides-march-29
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S 2060 Lecture 2 – Data Literacy & Data Mode
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Transcript of Lecture2 slides-march-29
BSYS 2060 Lecture 2 – Data Literacy & Data Modeling
Agenda
• Announcements• Digital Literacy• Data Modeling• Relationship Types• Example
Source: CC by 2.0, http://www.flickr.com/photos/bobjudge/3569973941/
Bring headphones to all labs from here on in!
https://zenportfolios.ca/bcit-bsys-2060-2012/week-0/
Announcements
• If you didn’t already do the “Week 0” exercise, you should do ASAP!
• Sign up for Lynda.com ASAP– $21.67 US for duration of semester– Videos to watch will be assigned shortly after today’s lecture– Bring your headphones to all future labs!
• Join the BSYS 2060 group on zenportfolios.ca if you didn’t already– Upload an avatar if you didn’t already– We will start using this online group more in the weeks to
come, especially for the project
If you didn’t do this already…Go to zenportfolios.ca, log-in, click on Groups, search for 2060Then join the BSYS-2060-2012 group
Digital Literacy
http://www.nytimes.com/2012/03/28/technology/for-an-edge-on-the-internet-computer-code-gains-a-following.html?pagewanted=all
“Inasmuch as you need to know how to read English, you need to have some understanding of the code that builds the Web,” said Sarah Henry, 39, an investment manager who lives in Wayne, Pa. “It is fundamental to the way the world is organized and the way people think about things these days.”
We live in an information age where data is king.
Data often most valuable asset of a companye.g. Aeroplan worth more than Air Canada
We live in a data mash-up world.
WordPress that uses open sourceMySQL database back-end
Twitter API / Integration
Take control of your data. Best thing is to buy your own domain nameand build your own site and web presence there.
http://jacobjpope.com
Where does data belong?
You control completely
You don’t control the data at all
Self-hostedWebsite containing all your data
convenientNot so easy...
Trend is towards you controlling your data
Diaspora
Many “fly by night” Web 2.0 apps
The average middle aged person has their data spread out overA 1000 different database locations
Who owns data?
Building a database for an organization?
What is the organization’s mission?
What is the project’s mission?
What data is required to make good decisions or for other reporting needs?
What data is currently being collected?
How is the data collected being used?
What data should be collected?
What are the main data entities?These will become your tables
What are the required fields and field data types?
What are the relationships between the tables?
Select your tools?e.g. MS Access, MS SQL, MySQL, OracleWhat is being used now if anything?
Be careful of the hammer!To a hammer, everything looks like a nail. If you only know MS Access, you may see always see MS Access as the solution even when it’s not. If you only know MS Excel, it seems like the perfect choice!
Source:http://www.flickr.com/photos/fixersphotos/3199566032/
Normalization
A brief introduction to the first three forms...
“Normalization”
• In the field of relational database design, normalization is a systematic way of ensuring that a database structure is suitable for general-purpose querying and free of certain undesirable characteristics—insertion, update, and deletion anomalies—that could lead to a loss of data integrity.
Codd, E.F. The Relational Model for Database Management: Version 2. Addison-Wesley (1990), p. 271
“...insertion, update, and deletion anomalies...”
Until a Course Code is assigned to this record, it can not be inserted in the table
“...insertion, update, and deletion anomalies...”
An edit made to one record may not be made to ALL records for the same employee
“...insertion, update, and deletion anomalies...”
If the Course Code is deleted the information for the Faculty Member will be lost.
Three Normal Forms
• 1NF– Eliminate repeating groups– No redundant data
• 2NF– Eliminate independent data– All fields depend on Primary Key
• 3NF– Eliminate dependency on non-key fields– Fields do not depend on each other
Un-Normalized Table (i.e. Excel)
First Normal Form (1NF)
0NF – “un-normalized”
1NF
Second Normal Form (2NF)
1NF
2NF
Third Normal Form (3NF)
2NF
3NF
