Managing Data

Question 1

What is the difference between a Online Database and a Local Database?

Answer 1

An online database is only accessible from the Internet, whereas a local database is stored locally on the attached device.

Question 2

What is the difference between a Distributed Database and a Centralized Database?

Answer 2

A distributed database is physically situated in two or more devices, connected by a communications network. A centralized database is stored at a central location, accessible from multiple points.

Question 3

What is the difference between a Data Warehouse and a Data Mart?

Answer 3

A data warehouse is a huge database that contains data from the whole business. A data mart contains less data from a section of the business. Data marts are easier and faster to access, and cheaper.

Question 4

What is the role of Data Mining?

Answer 4

Businesses can use data mining to find patterns and relationships amongst data, using mathematical methods. Can be used to describe patterns/trends and predict future events.

Question 5

What are some ethical implications of data marts, warehouses and mining?

Answer 5

• Privacy - Might collect large amounts of sensitive information.
• Discrimination - May reveal patterns that lead to discrimination.
• Transparency - Companies must be clear on what data they collect and how it will be used.
• Security - Could be appealing targets for hackers.

Question 6

What is a Data Dictionary?

Answer 6

A Data Dictionary is a table that describes the data that is in and/or is going to be in a Database table. Is referred to by staff to fill out dictionary.

Question 7

What are the elements of a Data Dictionary?

Answer 7

• Element Name
• Data Type
• Size
• Default Value
• Description
• Constraints (e.g. Required)

Question 8

What is Data?

Answer 8

A collection of values.

Question 9

What is Data Duplication?

Answer 9

The repetition of data.

Question 10

What is Data Redundancy?

Answer 10

Where the same piece of data is held in two separate places in a database.

Question 11

What is Data Manipulation?

Answer 11

The modification of information to make it easier to read or make more structured. E.g. Ordering by alphabetical order, using SQL commands.

Question 12

What is Data Security?

Answer 12

Ensuring that data is stored and transmitted securely so that unauthorised people or organisations cannot access it.

Question 13

What is Data Integrity?

Answer 13

Data integrity reflects the quality of data. Ensures data accuracy and consistency over the database’s entire lifecycle by making sure data is recorded as intended.

Question 14

What are the 3 types of Data Integrity?

Answer 14

1. Referential Integrity - Ensures primary and foreign keys are kept the same and must not be NULL.
2. Domain Integrity - Validity of entries in a column by restricting data types, format etc.
3. Entity Integrity - Each record has a unique primary key, each row must define a unique entity.

Question 15

What are three types of Data Anomalies?

Answer 15

1. Update - When duplicated data is updated, requiring all instances to be updated.
2. Insert - When data cannot be inserted without the presence of other attributes.
3. Deletion - When deleting a record also deletes other information that only occurs in that record.

Question 16

What is a Validation Rule?

Answer 16

A validation rule is a check or a constraint that is applied to data on entry.

Question 17

What is an Input Mask?

Answer 17

Input masks control the shape of data that is inserted into a database.
Input masks prevent data of the wrong shape being entered at all.

Question 18

What are the 1st, 2nd and 3rd Normal Forms?

Answer 18

1st - All rows must be unique and all cells must contain atomic values (non divisible).
2nd - No partial dependencies. Each value must be dependent on whole primary key, only broken when using composite keys.
3rd - No transitive dependencies. Each value depends only on the primary key.

Question 19

What are Open Systems?

Answer 19

Computer systems that provide a combination of interoperability, portability and open software standards. Create common ways of transmitting data, structuring databases and querying data.

Question 20

What is role of Open Systems?

Answer 20

• Database Connectivity - Allows databases to communicate though standardised protocols.
• Database Development - Provide tools and resources to create databases.
• Database Management - Provide replication, backup and recovery tools to manage databases.
• Data-Driven Websites - Provide resources to create data-driven websites that handle large amounts of data.

Question 21

What are the 4 Design Considerations for Visual Interfaces within Database Systems?

Answer 21

• Readability - How easy it is to read (font, colours)?
• Navigation - How easy it is to navigate the interface (back/forward buttons)?
• Logical Order - Is the interface logical (entering first name before last name)?
• Inclusivity - Does it cater to a variety of people (text-to-speech, languages)?

Question 22

What are the impacts of Privacy Laws on storage of data?

Answer 22

The Privacy Act 1988 regulates management, storing, access and correction of personal information about individuals. Businesses have to take precautions such as privacy policies to protect data.

Question 23

What is the purpose of Database Documentation for the user?

Answer 23

Database Documentation such as user manuals and data dictionaries allow the user to navigate and enter data into database.