1. Creating databases for web applications
New example: last lecture
Systems design. ER diagrams. Data flow diagrams. Storyboards.
Homework: Plan database and applications for a library: produce ERD and DFD

2. Added example Students: name, gpa, department
Go to last lecture for code

3. System analysis and design
Tools for planning
communication with clients (specific diagrams may not always be shown, but used to support discussion)
communication with builders
Attempt to focus on function before implementation
logical design versus physical design
non-tech
meaning of
term
Historically, a problem with computer work has been the rush to implementation, independent of understanding of desired function.

4. Models Information model = Entity relationship diagrams
Ask yourself: what is the critical information? What are the relationships (what fields in one table point to other records?)
Process model = data flow
What are the (main) processes? Who initiates these processes? What data stores are used and/or changed?
Story board
What are the Web pages—the interfaces to the user (client/player/employee)? What is the flow from one Web page to another?
There are other modeling schemes, for example, object oriented modeling.

5. ER models
Done before creating the tables as part of planning and after creating the tables, as documentation
Logical/analysis level (what is in examples here) just defines fields and relationships. Physical/Design/Implementation level: data types and also estimates on number of records.
I'm trying to use all the terms typically used.

6. Entity-relationship
Entity = the things (products, people, places, business concepts)
attributes = fields = properties
Relationships = connections between things, as represented by a field in one table (attribute of an entity) pointing to an entity.

7. Primary keys and foreign keys
A field (attribute) that uniquely defines a record in a table can be its primary key.
sometimes generated automatically by dbms
In another table, the way to refer to this record would be by using the primary key value. This is called a foreign key in that other table.

8. Entity Relationship diagrams
Blocks represent the records in the table. Typically, they list all the fields.
Lines between the blocks represent relationships. The marks on the lines indicate the numbers, e.g., one to many, one to one. They also indicate what a minimum would be.
0 means that an entity in one table may not be referenced in the other at all.

9. Example: trivia quiz Tables are Questions Players
History (that is, a question was asked [of] a player on a specific date, with outcome correct or not correct
Each item in History relates to a specific player and a specific question

10. Question databank table question_id Question Answer (answer pattern)
Players table
player_id
Player name
Score
lastplayed date
Question databank table
question_id
Question
Answer (answer pattern)
Value
Category
history table
question_id
player_id
whenplayed
correct
ER diagram for quiz show. Note: the history table has relations with each of the other two tables. The primary key of the history table is the pair: question_id and player_id.

11. Course pre-req example
In this design, each course has at most one pre-requisite course.

12. Course course title Division Pre-requisite
simple version: only works if there are only 0 or 1 pre-requisites. However, a course can be a pre-requisite
for zero or many courses.

13. Course pre-reqs, more complete
Each course can have no, 1, or any number of pre-requisites.
TWO TABLES!
Courses
Statements of pre-reqs

14. Statement of pre-requisites Course to be taken
pre-required course (prior course)
Course
Course title
Division
Each statement of pre-requisites refers to exactly one course and
exactly one 'pre-req'. A course can be in either position, zero, one
or several times.
Creating Web Documents is a pre-req for
Creating Dynamic Web Docs & Creating DBs for Web
Some courses may have pre-requisites of more than one course.
The second example may not be true. In fact, Purchase registration does not monitor or enforce ANY pre-requisites!
This could be even more complicated: pre-requisites may be satisfied by one of several courses….

15. clip tag table
Video archive application has table of clips and tags similar to the pre-req tables.
Demonstrate
NOTE: I removed entries on 2 videos and then restored them with shorter names!

16. Data design
Sometimes done by taking the artifacts (forms, reports, screens) and writing down all those fields into first draft of records
These artifacts can be from the current system or the proposed materials for a new system
Apply a technique called normalization to get well-defined entities and relationships.
First step is making sure each record has fixed number of fields.
For example, not indefinite number of pre-reqs
Subsequent steps ensure that data is not repeated, so information only needs to be updated in one place
Make customer data be in a customer file NOT in each transaction file
EXTRA CREDIT opportunity for posting
We may cover this later in course.

17. Process diagram Focus on Blocks Connections processes
agents (this could be people in specific roles or 'the system' triggered by events, including a time condition)
data stores: more general term than databases
Connections
Agent engaged with process
Process using data store
This approach can be modified to an event driven approach.

18. Player Questions DB Play game History DB Edit questions Player scores
Data flow diagram (process diagram) for quiz show
Player
Questions DB
Play game
History DB
Edit questions
Player scores
Data flow diagram (process diagram) for quiz show
Editor

19. Story board more implementation based than the others
Therefore, part of system build, not system design, or, perhaps, System Physical Design not Logical Design
focus on the scripts and how the scripts call each other
Story board is term from advertising, animation, ?

20. Include/Required file: opendbq Create quiz tables (php only)
Input Questions (handles form input)
Choose category
Show scores
Ask question
Story board. Thicker Links with round bases represent handling of form. Names are readable versions of file names.
Check answer
Clear tables

21. Entities for store Initial design catalog of products orders
one or more ordered items
customer list
Enhanced design
Need 1 more table: call it ordered items
Normalization would tell you you need a 4th entity for the ordered items distinct from the orders. Since I've done
this many times before, I know to do this.

22. Customer list Customer ID first name last name Billing information
ER diagram for on-line store
Customer list
Customer ID
first name
last name
Billing information
Password
Product catalog
Product id
Product name
Picture
Cost
Order list
Order ID
Customer ID
Date
Status
Total
Ordered items
Order ID
Product
Quantity
ER diagram for on-line store. The connectors, often called crow’s feet, indicate the cardinality, the possible
numbers of the relationships: each ordered item relates to exactly 1 product and exactly one order.
Each order is for exactly one customer. However, a customer can have zero or more orders.
An order includes at least one ordered item (the 1 is indicated by the vertical line.)

23. Billing system (timed event)
Data flow (process) diagram for on-line store.
Catalog
Browse/Order
Customer
Customer list
Billing
Current orders
Ordered items
Shipping
Billing system (timed event)
Data flow (process) diagram for on-line store. Note that this is the information/data flow, not the flow of goods.
The orange indicates processes and associated agents NOT implemented in the example I will present. Note: this diagram does not distinguish between the (personal) shopping cart, which is a list of items, and the ordered items for all customers.
Shipping clerk
Note that this is the information/data flow, not the flow of goods. The shipping operation produces a physical product: the collection of ordered items, packed and set off for delivery.

24. Create tables (php only) Include/require: opendbo
Storyboard of partial implementation: ordering
Create tables (php only)
Include/require: opendbo
Input products
Delete current customer cookie
Order product
Story board. Thicker Links with round bases represent handling of form. Names are readable versions of file names.
makeorder
Submit order
Shopping cart
Include/require: displaycartfunction

25. Video archive: main table
$fields = "fileaddr varchar(15) NOT NULL,cliptitle varchar(50) NOT NULL,";
$fields = $fields . "clipdate varchar(10),clipgroup varchar(15), sequence int(6), PRIMARY KEY (fileaddr)";
NOTE: example of primary key NOT created by DBMS.

26. Video archive: tag table
$fields = "fileaddr varchar(15) NOT NULL,tag varchar(20) NOT NULL";

27. ER for video clip archive
Video clips
File addr
Clip title
Clip group
Sequence
Tags
File addr
Tag

28. Grid Design example
Designs generated in Flash application stored as variable length strings in database
Alternative would be to store design elements, like the ordered items
Application could use sign on procedure!

29. ER for design Members Member id Member name Member email
Member password
Designs
Design id
Member id
Design name
Design string

30. Song with features example
Bare bones
Song table and Feature table plus
A song can have 0 or more features
Intention is to provide way of detecting songs similar to a given song
Complex SQL statement!

31. Song features feature id name description song id Name Description
Year
feature of song
fisid
fid

32. Song with features storyboard
createtables.php
deletefeaturesinsongs.php
listallfeaturesinsongs.php
addsong.html
addsong.php
opendbe.php (included in
all php files)
addfeature.html
addfeature.php
addfeaturestosong1.php
addfeaturestosong2.php
findothers1.php
findothers2.php

33. Songs with features DFD
Add songs
Identify songs
Admin
Finder
Song info
Add feature
Add features to song
Edit info

34. Agents
Of course in these toy applications such as the songs with features, there is just one agent (me!) but
Important to plan what are roles of system builders versus system users
Some social networking song sites do allow users to add songs, specify features, add features, etc.

35. Opportunity for improvement
Functions mentioned but not implemented (in orange)
Navigation could be better
specifically, going back or 'coming out of' steps. Where to go
Teams will review and enhance these projects and present whole thing to the class.
Mike noted that problems with navigation.

36. Homework Design ER and DFD for a library.
YOUR job is to define entities, relationships, agents, data stores, processes.
Logical design, not physical design
Note: a data store could be manual. Don't be concerned with that.