Databases.

Databases.

Revision tip: Focus on the things you find difficult first.

Task Time (minutes) a

1. Complete self assessment sheet. 22. Read through the chapter on databases. 153. Work through the questions on the revisiontemplate focusing on weaker areas first.

25

4. Attempt the multiple choice test on Edmodo. 105. Attempt the past paper exam questions. 206. Mark past paper exam paper questions. 157. Read through the chapter on databases. 158. Attempt the multiple choice test on Edmodo again. 10

“Every lesson counts – don’t waste a minute.”

Importance of databases.2. Most organisations depend on their databases in order to operate.

Because of this databases need to be:(4

marks)i) ……………………………………………………....................................................................................................................................................................

ii) ……………………………………………………....................................................................................................................................................................

iii) ……………………………………………………....................................................................................................................................................................

iv) ……………………………………………………....................................................................................................................................................................

1. Give a definition of a database.(2

marks)……………………………………………………................................................................................................................................................................……………………………………………………..................................................................................................................................................................……………………………………………………..................................................................................................................................................................……………………………………………………..................................................................................................................................................................……………………………………………………..................................................................................................................................................................

Data security & data integrity Exam tip: Remember that validation can be set up in any way that the database designer wants.

1. Explain the term ‘validation’.(3

marks)……………………………………………………................................................................................................................................................................……………………………………………………..................................................................................................................................................................……………………………………………………..................................................................................................................................................................……………………………………………………..................................................................................................................................................................……………………………………………………..................................................................................................................................................................2. What is meant by a range check?

(2 marks)

……………………………………………………................................................................................................................................................................……………………………………………………..................................................................................................................................................................……………………………………………………..................................................................................................................................................................……………………………………………………............................................

3. Explain the term ‘verification’.(2

marks)……………………………………………………................................................................................................................................................................……………………………………………………..................................................................................................................................................................……………………………………………………............................................……………………………………………………..................................................................................................................................................................4. What is a ‘check digit’.

(2 marks)

……………………………………………………................................................................................................................................................................……………………………………………………..................................................................................................................................................................…………………………………………………….................................................................................................................................................................……………………………………………………............................................5. A data table is set up to hold personal details of customers for an

online business. Describe how the following fields would be validated: (8

marks)(a) Surname……………………………………………………................................................................................................................................................................

(b) Date of birth……………………………………………………................................................................................................................................................................

(c) Gender ……………………………………………………................................................................................................................................................................

(d) Credit limit……………………………………………………................................................................................................................................................................

Data redundancy

(a) Define the term data redundancy.(1 mark)

……………………………………………………................................................................................................................................................................……………………………………………………............................................

(b) Explain how data redundancy affects this table.(2 marks)

……………………………………………………................................................................................................................................................................……………………………………………………..................................................................................................................................................................

(c) Explain what problems might occur as a result of the redundancy in this example. (2 marks)

……………………………………………………................................................................................................................................................................……………………………………………………..................................................................................................................................................................

(d) Explain how the data could be stored to eliminate this problem.(2 marks)

……………………………………………………................................................................................................................................................................……………………………………………………..................................................................................................................................................................

1. What is a flat file database?(1

mark)……………………………………………………................................................................................................................................................................……………………………………………………..................................................................................................................................................................2. Explain what a relational database is.

(3 marks)

……………………………………………………................................................................................................................................................................……………………………………………………..................................................................................................................................................................…………………………………………………….................................................................................................................................................................…………………………………………………….................................................................................................................................................................……………………………………………………............................................

6. Here is part of a database of customer details:

Flat file vs. Relational

Database Management System (DBMS)4. Give the data that would result from running the following queries on

the table below:1. Describe four features of a typical DBMS.

(4 marks)

i) ……………………………………………………....................................................................................................................................................................

ii) ……………………………………………………....................................................................................................................................................................

iii) ……………………………………………………....................................................................................................................................................................

iv) ……………………………………………………....................................................................................................................................................................

2. Explain the difference between an entity and a table.(2

marks)…………………………………………………….................................................................................................................................................................…………………………………………………….................................................................................................................................................................……………………………………………………............................................……………………………………………………............................................……………………………………………………............................................……………………………………………………............................................

3. Describe two ways in which a query can be constructed.(2

marks)…………………………………………………….................................................................................................................................................................…………………………………………………….................................................................................................................................................................……………………………………………………............................................……………………………………………………............................................……………………………………………………............................................……………………………………………………............................................

(8 marks)

(a) SELECT Surname, City WHERE Sex = “m”……………………………………………………................................................................................................................................................................

(b) SELECT Surname, City WHERE Sex = “m” AND Years in employment > 3……………………………………………………................................................................................................................................................................

(c) SELECT Surname, Salary WHERE Years in employment < 4 AND Salary > 35000

……………………………………………………................................................................................................................................................................

(d) SELECT Surname WHERE City = “Birmingham” OR Years in employment = 4

……………………………………………………................................................................................................................................................................

5. Construct a query that would produce the following result:

(a) A list of surnames and salaries of all female employees who live inBirmingham. (2

marks)……………………………………………………................................................................................................................................................................……………………………………………………............................................

Past paper exam questions.2011 past paper.

Past paper answers.2011 past paper. Notes: What do I need to improve?

Past paper exam questions.2011 past paper.

Past paper answers.2011 past paper. Notes: What do I need to improve?

Past paper exam questions.2012 past paper.

Long answer question.

@CES_teach

Past paper answers.2012 past paper.

Notes: What do I need to improve?

Past paper exam questions.2013 past paper.

Past paper answers.2013 past paper.

Notes: What do I need to improve?