This is an introduction to relationships and normalization and how to model relationships to design databases.

1. Quentin Christensen
quentin.christensen@live.com

2. Requirements Gathering
 Relationship approach – gather information
requirements, organize into entities, form relations,
and add desired fields
 Data requirements approach – gather information
requirements about individual fields, organize into
entities, create relationships between the entities

3. What is a relation?
Rank Country Population
1 China 1,136,429,638
2 India 849,638,000
3 United States 258,115,725
4 Indonesia 179,247,783
5 Brazil 150,367,000

4. What is a relationship?
Rank Country Population
1 China 1,136,429,638
2 India 849,638,000
3 United States 258,115,725
4 Indonesia 179,247,783
5 Brazil 150,367,000
Country Province/State
China Anhui
India Assam
United States Washington
Canada British Columbia
Brazil Bahia

5. Normalization
 1st form – All cells are atomic
 2nd form – all rows in a relation have a unique
identifier and are dependent on a primary or candidate
key
 3rd form – no rows are transitively dependent – all
attributes must rely on the primary key

6. Conceptual Modeling

7. Conceptual Modeling

8. Logical Modeling

9. Logical Modeling

10. Physical Modeling
 How much data in each table?
 How many operations on each table?
 What type of operations will be performed?

11. Prototyping
 Create the database tables
 Create the operations that will be performed
 Put in some sample data
 Try it out
 Are the results what you expected?

12. Refinement
 Give users scenarios
 Ask them about the results that are returned
 See if there is additional information you need
 Do performance testing

13. Creating a data model for structuring unstructured
data about generic objects. + support for versioning,
user evaluation of content, and tagging

14. The Big Idea
 A wiki that supports structured
properties about generic items
 Post articles, reviews, comments
about wikis
 Rate user content
 Associate structured properties
(text) or ratings (numbers) that
can be shared between different
types of items

15. Project Goals
 Wiki – support user collaboration and versioning
 Generic content – support data about different objects
 User ratings – allow users to rate content and items
 Dynamic submission – application changes as the
properties of items change

16. Persona
 Pam the Ninja
 Has trouble finding ninja movies and games to enjoy
 Dislikes regular review sites because they may be
biased or influenced by advertisers
 Hates pirates

17. User Scenarios / Tasks
 Create a user
 Log in
 Update a wiki entry
 Post comments, reviews, and articles
 Rate a wiki entry by posting a review
 Vote on quality of articles and reviews
 View a users profile
 Create a wiki entry

18. Conceptual Model

19. Logical Model

20. Physical Model
Table Rows Field Freq/day Type
article 1,000,000predicate: pageId 50,000Read
join: articleBridge ON articleId predicate: pageId 50,000Read
predicate: articleId 30,000Read
predicate: userId 5,000Read
300Insert
articleBridge 1,200,000join: article ON articleId predicate: pageId 50,000Read
300Insert
articleType 10 500Read
articleVotes 3,000,000 2,000Insert
predicate: userId 50,000Read
avgRating predicate: pageId 10,000Read
join: avgRating on wikIEntry predicate: pageId 10,000Read
comments 5,000,000predicate: pageId 50,000Read
predicate: userId 5,000Read
2,000Insert
predicate: commentId 50,000Read
hits 50,000,000predicate: id, tableName, ip (index necessary) 150,000Read
100,000Insert

21. Physical Model
admin
about
article
copyright
comment
browse
createreview
index
postarticle
postcomment processcomment
processarticle
processreview
createuser
createwiki
processuser
processwiki
processwikiediteditwiki
review
search support terms
updateuseruser
wikiedit
wikientry
blog
login

22. Usability Testing
 Two users
 Tested on ability to complete user
tasks – register, login, create wiki
entry, evaluate content etc.
Results:
 Both users successfully able to
complete all tasks

23. Shneiderman’s InfoVis Tasks
 Overview – index page
 Filter – by item type of the wiki (browse)
 Details on Demand – linking to wiki entry
 Relate – properties / tags

24. Conclusion
Goals:
 Wiki – wiki entries, wiki edits
 Generic content – item type categorizations, text
fields, properties
 User ratings – reviews, ratings
 Dynamic submissions – forms for reviews, articles, and
wiki entries dynamically created based on current
state of database