Relational Database Design, Implementation And Use

Question 1

Explain the purpose of a data dictionary

Answer 1

The purpose of a data dictionary is to list all the files in the database, including the number of records, field names and types.

Question 2

How do scripts such as SQL and PHP extract, amend, insert and delete data in a database?

Answer 2

Host languages are used to send the SQL instruction to database management software which processes the instruction.

Question 3

How are calculations handled by relational databases?

Answer 3

Results of these calculations are obtained and presented using queries and reports. A database should not store calculated data permanently - as this would slow response times to future queries.

Question 4

Explain the purpose of a report and how a report is generated

Answer 4

Is used to dusk at the results of a query as a formatted document.
Contains database fields to be displayed, along with additional labels, text and graphics used to present the information in a user friendly way.
A query may be needed first to produce this report
Results of calculations are often displayed in the report footer section.

Question 5

What is the need to refine a design (normalisation) in order to reduce redundancy in a relational database?

Answer 5

So that data can be inserted, modified and deleted in just one table.
Many-to-many relationships expanded to two one-to-many relationships so entities will not be hidden.

Question 6

Normalisation

Answer 6

Prevents the same fields being present in more than one table
Data can be inserted, deleted and modified in just one table
Achieved by insertion of further entities and relationships into the diagram

Question 6

Form uses

Answer 6

To enter data into database tables

Forms can be used to create a user interface for a database

Question 7

Query use

Answer 7

Used to search one or more database tables using entered criteria
Query returns appropriate results when executed
SQL can be used to query a database

Question 8

How are SQL instructions carried out on a database?

Answer 8

Embedded in other host languages
Host league be sends the SQL instruction to Access
Access processes the instruction
If the instruction is a query then results will be returned and dealt with by the host language

Question 9

Data in a calculation

Answer 9

Results are obtained and presented using queries and reports
Calculated data is not stored permanently as this would result in a larger database file, slowing response times to future queries

Question 10

Reports

Answer 10

A formatted document used to display query results

Contains database fields, text, labels and graphics to present the information in a user friendly way