CHP2

Question 1

What are the disadvantages of file based system?

Answer 1

• Time-consuming, high-level activity
• Making changes in existing file structure can be difficult
• Concurrent data = can be shared to read with people but changes cannot be made simultaneously

Question 2

What is data redundancy

Answer 2

• Results in data inconsistency
• Different and conflicting versions of the same data appear in different places at the same time.

Question 3

What is anomaly and explain different types of data anomaly

Answer 3

• Data anomalies are develop when data becomes redundant.
  1. Update anomalies
  2. Insertion anomalies
  3. Deletion anomalies

Question 4

Describe 3 functions of DBMS

Answer 4

1. Data dictionary management = defines data elements and their relationships
2. Data storage management = stores data and related data entry forms, etc
3. Data transformation and presentation = use commands to physically located and retrieve data

Question 5

Definition of Field, Record, and File

Answer 5

Field - A character or group of characters (alphabetical or numeric) is used to define and store data. Also called a column in a database
Record - Known as row in a database. A logically connect set of one or more fields for instance, describing a person’s age, location, name, id
File - A collection of related records, consisting of fields and attributes.