Databases – theory only

Question 1

What is a database?

Answer 1

A database is a software program used to store data in a structured way.

Question 2

What is a field?

Answer 2

Each is a single item of data and has a field name, which is used to identify it within a database. Remember to use underscores for spaces

Question 3

What is a record?

Answer 3

Collection of fields which may contain different data types

Question 4

What is a flat file database?

Answer 4

Flat File database: stores data in one table, which is organised by rows and columns.

Question 5

What is a relational database?

Answer 5

Relational database: stores data in more that one linked table, stored in a file. They are designed so that the same data is not stored many times. The links are called relations.

Question 6

What are the advantages of flat file database?

Answer 6

• All records are stored in one place
• Easy to understand
• Good option for small databases
• Requires less hardware and software components

Question 7

What are the disadvantages of flat file database?

Answer 7

• Harder to update
• Harder to change data format
• Can only hold one table not multiple
• Data inconsistency

Question 8

What are the advantages of relational databases?

Answer 8

• Since there are several tables, some of which can be made to be confidential if necessary
• Multiple users will be able to access a relational database at the same time
• Does not requite any specific path to access data
• Reduces data inconsistency and better for accuracy

Question 9

What are the disadvantages of relational databases?

Answer 9

• Some relational databases have a limit on field lengths
• They are isolated databases
• While using the relational database over multiple servers, its structure changes and becomes difficult to handle, especially when the quantity of the data is large
• Harder to search

Question 10

What is the alphanumeric data type?

Answer 10

Used to store text and numbers not used for calculations. This is called a ‘text’ field in Microsoft Access.

Question 11

What is the numeric data type?

Answer 11

A data type that is used to store numeric values that may be used for calculations

Question 12

What are the sub types of numeric data?

Answer 12

• Integer: sub-type which stores whole numbers
• Decimal: sub-type, which will allow a large number of decimal places, or a specified restricted number if this is set in the field properties when the database is created
• Currency: sub-type, money
• Boolean - data type that stores data as 0/-1 but can display it as Yes/No. A tick box can be used as Boolean and gender

Question 13

What is a primary key?

Answer 13

Most tables will have a primary key field that holds unique data and is the field used to identify that record.

Question 14

What is a foreign key?

Answer 14

A foreign key field in one data table that stores values from a primary key field in another table.

Question 15

What do you have to include for caluclations?

Answer 15

What you want to calculate: [x_y][7_y]
e.g. Total_Costs: [Meal_Cost][Guest]

Question 16

What is a report?

Answer 16

A database report is a formatted presentation of data from a database that provides structured information for decision-making

Question 17

What is a query?

Answer 17

Used to retrieve specific information from one or more tables in a database. Queries allow you to ask questions about your data and extract the answers based on specified criteria.

Question 18

What is a file?

Answer 18

Each file is an organised collection or records stored together. It can have one or more tables within it.

Question 19

What is a calculated control?

Answer 19

Is a feature that allows you to create custom calculations within forms and reports. It enables you to display calculated values based on expressions involving fields, constants, functions, and operators.