File Design Flashcards
(19 cards)
Field
A single data item that can be grouped together or split
Records
A collection of related fields.
Master file
Principal file held by an organisation that stores basic details about crucial aspects of the business
e.g. student details in a school, stock in a supermarket
Transaction file
Day-to-day information generated from business activities. Used to update master file.
e.g. how many items are sold in a supermarket, to keep track of stocks
Serial file
in order of when it was added
Sequential file
in order of a key field
Indexed Sequential file system
having an index to tell you where files are in a sequential file system
Random Access File
read or write information anywhere in a file
Overflow area
When you have two files that need to access the same memory address location.
Methods of file security
Physical security
File backup
Transaction log
Archiving files
Passwords
Encryption
File security types & how they help
Physical security
Anything physical to protect a system
Stops unauthorised physical access
File security types & how they help
File backup
Having a backup of each of your files
Prevents loss of data if something goes wrong
File security types & how they help
Transaction log
A log of everything happening on a computer
Allows you to check what happened if something goes wrong
File security types & how they help
Archiving files
Saving storage space by keeping important files that are out of use on a separate device
Stops you having to delete old files to make room for new ones
File security types & how they help
Passwords
Allows permitted access to only certain individuals
File security types & how they help
Encryption
Prevents hackers being able to understand any stolen data
Data Validation
Checks that the data is acceptable using:
Presence
Range
Type
Format
Look-up
Length
Check Digit
Data Verification
Checking that data has been transcribed properly using:
Screen verification (proof reading)
Double entry
ERD
Entity Relationship Diagram
Diagram used to illustrate a system and the entities and relationships within
