Relational Database Elements

Question 1

Gives examples of field types:

Answer 1

1. Text, such as ‘customer last name’
2. Memo, such as ‘notes’
3. Number, such as ‘# of units ordered’
4. Currency, such as ‘beginning account balance’
5. Date/time, such as ‘transaction date’
6. Yes/no, such as ‘credit approved’

Question 2

What is a primary key?

Answer 2

A field which uniquely identifies every record in a table. (Only 1)
- Primary key is UNDERLINED.

Question 3

What is a foreign key?

Answer 3

A primary key from one table that is also included in another table for purposes of linking.
- Foreign key is in brackets.
[Example]

Question 4

What is a compound primary key?

Answer 4

A set of fields which uniquely identify every record. (Just 2 of them)

Question 5

What is a query?

Answer 5

• ‘Power tool’ of relational databases
• Allow user to extract records based on specified criteria
• Queries store instructions, not data

Question 6

Give an example of a sample query for an employee table:

Answer 6

Query: Last name & First name of all purchasing agents.

Question 7

What would you classify this query as: What is the total cost of all inventory purchased by John Smith?

Answer 7

Compound query of employee, purchases, purchases/inventory tables

Question 8

What are the two purposes for using “forms”?

Answer 8

1. Entering data in tables (populating)

2. Looking up data

Question 9

What are some of the specialized elements of a form?

Answer 9

1. Drop-down lists
2. Radio buttons
3. Command buttons

Question 10

What are the design principles for form?

Answer 10

1. Title
2. White space (can’t be crowded)
3. Font size (usually Arial)
4. Element positioning

Question 11

What else do forms allow users to do?

Answer 11

Forms allow a user to interact with a database even if they know nothing about databases.

Question 12

What are reports?

Answer 12

1. Display output from one or more tables/queries
2. Can incorporate simple calculations
3. Same design considerations as forms

Question 13

What type of tables would you use in these given relationships: (1) many-to-many and (2) one-to-many?

Answer 13

1. Junction table

2. Put primary key of “one” in table for “many”

Question 14

What are tables?

Answer 14

Fundamental building block of relational databases.

• Organized in: (1) rows (records) and (2) columns (fields).
• New records are “cheap.” New fields are “expensive.”