chapter 18-databases

Question 1

what is

Answer 1

software program used to store data in a structured way, it includes data dn links between data items

Question 2

whatre the 3 ways databases store data

Answer 2

-fields (single item of dataw with a field name)
-records (collection of fields)
-files (organised collection of records)

Question 3

what are the 2 types of files

Answer 3

-flat file database
-relational database

Question 4

whats a flat file database

Answer 4

simple strucure where data held in td tables with rows and columns
stored in single file
suitable for uses w one type of data (ex car data) a

Question 5

whats a relational database

Answer 5

stores data in more than 1 linked table in a single file
used w more than 1 type of related data (ex cars sold and customers)

Question 6

whats the primary key

Answer 6

holds unique data (no records are the same)

Question 7

whats a foreign key

Answer 7

will link to primary key in another table (so data is only stored once)

Question 8

whatre the advantages and disadvantages of using a flat file database

Answer 8

adv-ideal for small databases with little duplicated data,easier to create
dis-takes more internal memory and storage,data may be duplicated so there can be entry errors

Question 9

whatre the advantages and disadvantages of using a relational database

Answer 9

adv-less memory and space,data isnt duplicated so fewer entry errors,difficul tto create

Question 10

what are the 3 diff data types

Answer 10

-alpha numeric (text and numbers,short or long text)
-numeric (integer,decimal,currency,date and time)
-boolean (store data in 0 or -1 to represent yes and no or true or false

Question 11

why are forms made

Answer 11

to collect data to add to a database

Question 12

whatre the features of a good form

Answer 12

-title
-instructions on how to complete form
-clear questions (closed where possible)
-boxes for answers
-appropriate sizes of answer box
-small fields grouped to categories
-no crodwd fields
-fills page
-no large areas of space
-collect only relavent data

Question 13

whatre queries used for

Answer 13

to find data/filter through data in a database

Question 13

whatre the 3 query crieias

Answer 13

and (both must be ther)
or (either 1)
wildcards (like “x”)

Question 14

whatre the different operators

Answer 14

> greater than

<less than
= equal to

Question 15

when are wildcards used

Answer 15

• when you want to find a certain word within a phrase
  like “x” if you wanted words staring with x
  like “x” if you want words ending with x
  like “x” if you want words containing x

Question 16

how do you create a calculated field

Answer 16

go to query and creata a new one
using
-namecalculatedfield:[exisingfield]operator[exisingfield]
ex- tax:[price]*2 or profit:[sales]-[cost]

Question 16

explain why ranges should be changed to cell refrences (3)

Answer 16

Used if the range of cells is to be used many times
Easier to remember a name rather than cell references
Only has to type in the name rather than the cell references
Less chance of errors when entering the range
If the range of cells moves/copied the name still refers to the cells

Question 16

explain what IF(A2<>”“,VLOOKUP(A2,E3:F6,2), “”) does (5)

Answer 16

If the contents of A2 are not empty – 1 mark
Otherwise display a blank cell – 1 mark
Three from:
Looks up/searches the value in A2
Looks up in the range E3:F6
Retrieves/displays the corresponding value
From the second column of the range
Displays the value in A3

Question 16

describe the steps needed to create a relational database

Answer 16

Open database package
Select database tools
The teacher’s file and subject file would be imported to separate tables
A primary key is identified/set
The foreign key is identified in the subject table
Click/create/select relationships
The primary key is dragged to the foreign key
Save the database