Database: Relational Model and Entity Course Field

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Review Questions

6. What is an entity? Something about which we want to store data.

7. What is business logic? The set of rules that govern an organizations processes.

8. What is a relational database? A data base that organizes data into overlapping tables. They follow a set of very specific rules that ensure data contained in the database will be consistent.

9. How do the following terms relate to one another: record, table, field, primary key? Rows are called records, and columns are sometimes called fields. A primary key assigns that field’s special order to a table.

10. What purpose does a primary key serve in a table? It serves as the identifier for that table.

Practice Questions

1. Organize the following list of fields into the given entities.

Entity Student Field first name, last name

Entity Course Field title, day, time, credit hours

Entity Section Field room

2. Look at your latest grade report. Identify the fields and entities represented in the report.

Entity Title Field College Math, Linux Operating Systems, Strategies

Entity Grade Field A, A, A

Entity Section Field room

Entity Course Field GE192, IT250, TB133

Entity Credits Field 4, 4, 4

Entity Term Field Dec 11, Dec 11, Dec 11

3. Consider a table of data about employees. Which of the following fields are keys? Which one would you choose as the primary key? Employee ID Why? Because it is a unique number assigned to each employee.

4. Identify the fields and entities represented in the invoice form shown in exhibit 1-9. Match each field with the appropriate entity.

Primary Key-Item Id

Entity Description Field Superloud Speakers, SuperClearReceiver, SuperLoud Powerd Subwoofer

Entity Price Field 225.00, 400.00, 250.00

Entity Qty Field 2, 1, 1

Entity Ext Field 450.00, 400.00,...
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