1. Database Design
Week 12

2. myITLab EXAM NEXT WEEK IN CASE OF “TECHNICAL issues:
Be prepared to also do the PRACTICAL
exam next week
To ENSURE that your laptop is setup properly, please go to: BLACKBOARD > MyITLab resources  > myITLab SETTINGS, and setup your laptop with ALL these settings.  
If there are ANY TECHNICAL  issues, go to BLACKBOARD > MyITLab resources  > MyITLab Technical Support

3. Forms

4. Table Vs. Form Table Many records at a time
Some fields do not fit on one screen
Column and row formatting only
Can be confusing to new users
Form
1 record at a time
All fields can fit on 1 screen
Any formatting options you set-up
“User-friendly” and less-intimidating than tables

5. WHAT IS A FORM? • “electronic equivalent” to a paper form • allows you to create a custom layout for your data • more “visually appealing” for “data entry” • when you need to control which data is displayed or entered

6. Why Use Forms? Provide a “User-Oriented” interface to the data
Can focus on only 1 record at a time
Can create drop-down boxes & buttons for saving, deleting, printing or navigating etc.
Can create SUB-forms which access info from a RELATED TABLE
Only asks for specific information
Ability to use “non technical” terms
Should be designed around individual tasks

7. Fields in a Form
-The field LABELS in a form are like the labels on an application.
-The field TEXT BOXES are where you supply the data, like the blank lines on an application.
-If you need to DELETE a LABEL, you also need to DELETE its ASSOCIATED TEXT BOX

8. FORMS cont.
Forms are made up of CONTROLS, such as text boxes, buttons, document tabs, and drop-down lists, grouped in a way that makes them easy to use
The controls in the form are usually “bound”, or “linked” to the tables or queries in your database — but not always.
For example, a control that displays “Customer data” is probably bound to either the “Customer” table, or to a query that retrieves Customer data.
BUT: a form control that displays your corporate logo is NOT bound to a table field; it just points to the image it displays.

9. FORMS: 2 VIDEOS WORKING WITH FORMS CREATING FORMS
Part 2:

10. Watch video on FORMATTING forms: click on: the PLAY button
NOTE: Formatting FORMS is similar as Formatting REPORTS (except for “Design” view, where there are some additional options)
NOTE: If you create a “THEME” (DESIGN tab), it applies to the ENTIRE “Database”. If you want to apply it to the FORM, ONLY, go to the FORMAT tab
Watch video on FORMATTING forms: click on: the PLAY button

11. REPORTS Ways of generating printed output
Can create reports that show totals & grand totals of a value in a particular field
Reports give you the ability to present components of your database in an “easy-to-read”, printable format.
Access lets you create reports from both tables and queries.
NOTE: As with FORMS, if you create a “THEME” (DESIGN tab), it applies to the ENTIRE “Database”. If you want to apply it to the REPORT, ONLY, go to the FORMAT tab

12. REPORTS: 2 VIDEOS “CREATING REPORTS” FORMATTING REPORTS
click on: the PLAY button
FORMATTING REPORTS

13. Entities and Their Attributes
“Entities” represent something of importance
“Entities” are made up of several “Attributes” (the columns), which describe the tables:
ARTISTS
ArtistName
Gender
SONGS
SongTitle
Length

14. Review Tables / Entities
Tables (aka Entities) in the relational model are used to represent “things” in the real world.
Entities are made up of attributes
Attributes (columns/fields) are pieces of data that describe the entity
Rows are called records

15. What is a Primary Key?
The PRIMARY KEY of a table is the column whose values are different in every row
Should be 1st field
A field in the database that guarantees UNIQUENESS
Speeds “data retrieval”
RULE: Each record in a table must have a “PRIMARY KEY”.
In MS ACCESS a “Primary Key Field” is represented by a tiny gold key to the left of the Field Name

16. Primary Keys
Some entities have “ready-made” primary keys, for example:
Catalog codes
If an entity lacks a reliably unique field
Use a “system-assigned”: “AUTONUMBER”

17. What is a Foreign Key?
A field in a table that is the Primary Key of another TABLE.
A foreign key is used to indicate a relationship between 2 or more tables.
NOT every table has to have a Foreign key
Always a “NUMBER” type, linked to an “AUTONUMBER” type in another TABLE
Whenever you see: “MANY”—this will be the FOREIGN KEY

18. Three Basic Types of Relationships
CARDINALITY:
One to One (1:1)
One to Many (1:M)
Many to Many (M:M)
The 1 is the “PARENT”, and the M is the “CHILD”
Called the CARDINALITY of the relationship
The cardinality indicates the MAXIMUM number of RELATIONSHIPS
between the entities,
Whenever you see: “MANY”—this will be the FOREIGN
KEY

19. One to One Relationships
1:1 relationships exists when a single record in one table has 1 and only 1 corresponding record in another table, and vice versa
VERY RARE
When you created a table for something, when it really should only have been a “field”
The 1 should really have been an “attribute” of the other (table/entity) an attribute IMPROPERLY DEFINED as an entity
i.e. 1 customer, 1 address
“Address” should have been the attribute of the “Customer” table
EXAMPLE ON NEXT PAGE

20. One to One Example A voter can cast only one vote in an election.
A ballot paper can belong to only one voter.
So there will be a 1:1 relationship between a Voter and a Ballot Paper.
Voter
Ballot

21. One to Many Relationships
MOST COMMON
1:M or M:1
Relationship exists when a record can relate to 1 OR MORE records in a 2nd table but..
A record in the 2nd table can ONLY relate to 1 record in the 1st table
Example next page

22. One to Many Example
A person can own more than one car. A car can only have one owner.
Owner
Vehicle

23. Many to Many Example
A student can have more than one professor; the same professor can have many students
Student
Professor

24. Resolving Many to Many
Professor
Stud_Prof
Student
M:M is not allowed, as an attribute could have more than
1 value:
A “Multi-Valued Attribute”
Difficult to generate reports, or do searches
Would have to repeat attributes multiple times
Instead, we create a “JUNCTION” or “JOINER ENTITY”
The name of the joiner entity is often a COMBINATION of the 2 entities

25. Hybrid / Homework
View “14 Week Schedule” > Week 12 > 3rd Column