1.3.2 - databases

Question 1

What is meant by the term Primary Key?(1)

Answer 1

It is a field with a unique value. OR A unique Identifer.(1)

Question 2

What is meant by the term Foreign Key?(1)

Answer 2

A field that links a primary key in a second table.(1)

Question 3

What is meant by Referential Integrity?(1)

Answer 3

Database are consistent OR Each foregin Key links to a valid Primary Key.(1)

Question 4

What Does A.C.I.D stand for? (4)

Answer 4

Atomicity (1) Consistency(1) Isolation (1) Durability(1)

Question 5

What are the 3 types of Entity Relationship?(3)

Answer 5

One-to-One (1) Many-to-Many (1) Many-to-One(1)

Question 6

What is Flat File Database ?(1)

Answer 6

A single table (2) or a 2D table (1)

Question 7

What is a Referential Database?(1)

Answer 7

Multiple tables, linked by key fields (1)

Question 8

What are 4 Methods to Exchange Data (4)

Answer 8

CSV(1) XTML(1) JSON(1) Electronic Data Interchange (1)

Question 9

Why do we use SQL?(3)

Answer 9

Allows fast and efficient retrieval (1) deletion(1) and manipulation of data using simple commands.

Question 10

What are the 4 Methods for Capturing Data? (4)

Answer 10

Manual Entry (1) Optical Character Recognition {OCR}(1) Magnetic Ink Character Recognition {MICR}(1) Optical Mark Recogntion {OMR}(1)

Question 11

Give an Example of Manual Entry (1)

Answer 11

Focal Groups (1) Verbal Surveys (1)

Question 12

Give an Example of O.C.R (1)

Answer 12

Forms(1) Car Registration(1) Google Street-View (1)

Question 13

Give an Example of M.I.C.R (1)

Answer 13

Bank Cheques(1) Passports (1)

Question 14

Give an Example of O.M.R (1)

Answer 14

Multiple Choice Exams(1) Lottery Tickects (1)

Question 15

Why do we use Database Manipulation Languages?(5)

Answer 15

Specify Tables(1) Specifiy Fields(1) Specify Criteria(1) Specify Output Sorting(1) Use Boolean Expressions(1)

Question 16

Define a Record (1)

Answer 16

A collection of fields about the same person or item in a database(1)

Question 17

Define a Field (1)

Answer 17

A category of information(1)

Question 18

What is a Composite Primary Key? (1)

Answer 18

A primary Key generated by combining fields of each record to gaurantee uniqueness(1)

Question 19

Compare Flat-File Databases to Relational Databases.(4)

Answer 19

Flat Files: Limited amount of Data(1) Limited Technical Expertise required to use Flat File databases(1) Data format difficult to change (1) Not very secure(1) Relational Database: Easy to add Data(1) Easy to link to other applications(1) Save space by reducing redundant data(1) Improves Data Consistency (1) Easy to change data Format(1) Easy to control access to data(1)

Question 20

What does Atomicity mean in A.C.I.D?(1)

Answer 20

A transaction can be fully complete or not complete. It cannot be partially complete.(1)

Question 21

What does Consistency mean in A.C.I.D?(1)

Answer 21

A change in the database must retain the overall state of the database.(1)

Question 22

What does Isolation mean in A.C.I.D?(1)

Answer 22

Transaction must not interrupt one another (1)

Question 23

What does Durability mean in A.C.I.D?(1)

Answer 23

Changes made must not be lost to system faliure.(1)

Question 24

Why Normalise Databases?(2)

Answer 24

Reduces Redundant Data(1) Improves Data Integrity(1)

Question 25

What the requirements for First Normal Form (1NF)? (3)

Answer 25

Field names must be unique(1)Data is Atomic (1) Has a primary key(1)

Question 26

What the requriements for Second Normal Form (2NF)? (2)

Answer 26

It is in 1NF(1) No Partial Dependencies (1)

Question 27

Define Dependency (1)

Answer 27

A field all other fields are dependant on.(1)

Question 28

Define Partial Dependecy (1)

Answer 28

Field depending on parts of the primary key.(1)

Question 29

What the requriements for Third Normal Form (3NF)? (2)

Answer 29

It is in 2NF(1) No Transitive Dependencies(1)

Question 30

What is Transitive Dependency?(2)

Answer 30

A Non-Key Dependency (1) A value of a field is determined by the value of another field that is not the Primary Key (1)

Question 31

What is a Link Table? (2)

Answer 31

A table used to resolve Many-to-Many relationships(1) Resolves Partial dependencies.(1)

Question 32

What does * mean in SQL? (1)

Answer 32

SQL wildcard meaning ALL(1)

Question 33

What does % mean in SQL?(1)

Answer 33

SQL wildcard meaning ANYTHING(1)

Question 34

What is the SQL for Adding new Data to table? (1)

Answer 34

Insert Into (field1,field2)Values (value1,value2)(1)

Question 35

What Statement in SQL deletes Data?(1)

Answer 35

DELETE FROM (1)

Question 36

What Statement in SQL joins Two Tables togehter?(1)

Answer 36

JOIN ON(1)

Question 37

What Statement in SQL Deletes a Table? (1)

Answer 37

DROP TABLE (1)

Question 38

Name 2 SQL commands?(2)

Answer 38

SELECT(1) FROM(1) WHERE(1) LIKE(1) AND(1) OR(1) DELETE(1) INSERT(1) DROP(1) JOIN ON (1)

Question 39

What is a secondary key? (2)

Answer 39

An indexed field (1) that allows for easier searching (1)