Database Flashcards
Database
Consists of more than one table
Table
Consists of more than one record
A key
Uniquely identifies records in a table
Data verification
Checking data is input correctly
Example of data verification
Proof reading
Data validation what it does
Checks data is reasonable, sensible and within acceptable limits and if data present and correct type
If the data validation displays an error message
The data has been rejected
Five validation checks
Presence Check
Length check
Type check
Format check
Range check
Presence check
Ensures data is present and can’t be left blank or null
Length check
Correct number of characters
Type check
Check that all data is entered in the correct data type
Example of length check
Phone number
Type check example
Numeric, text and data
Type check example
Numeric, text and data
Format check
Data entered matches a predetermined pattern
Format check example
Postcode
Range check
Data is entered within a lower and upper limit
<
Less than
<=
Less than or equal to
>
Greater than
> =
Greater than or equal to
=
Equal to
<>
Not equal to
Ascending
Small to big
Descending
Big to small
Query criteria
Checks to present us with answers to our questions
Is null
Checks if blank
Isn’t null
Checks if data is present
Sorting
How it’s been sorted
Grouping
Any grouping (on what field)
Big data
Large amounts of data that has potential to be mined for information
What data to be mined
To identify patterns and trends
Provide further insight
3 Vs
Volume
Variety
Velocity
Volume
Amount of data stored by organisations
Volume by organisation
Store large amounts of data from different sources requiring large storage capacity hardware
What is volume measured in
Bytes
Variety
Different types of variables of data
Variety how data is stored and examples
Data is stored in many formats
Videos, images and not just text
Variety how it’s structured
Data can be structured, semi structured or unstructured
Velocity
Speed at which data can be processed
Description of velocity
Due to large amounts of data there’s no need to use powerful computer to process data more quickly
Velocity can’t be
Processed by normal means
Macro
Allows you to automate tasks and add functionality directly to your tables
Provided shortcuts for repetitive tasks
Report
Data is displayed in a user friendly format and prints the results of processing
Form
Used to add data to a database
Collects data about customers
String
Text
Character
Lower and upper case alphabet
Integer
Whole numbers
Float
Decimal numbers
Boolean
True or false
