Unit 3 Chap 9 & 10 (19 -29) Flashcards
What is data?
Raw facts & figures which haven’t been processed.
What is information?
Data with meaning added i.e. processed
Information =
Data + meaning
What should you consider when designing a data capture form? (7)
Leave enough space for answers
Make sure all necessary details are added
Layout should be simple & logical
Separate into parts if filled by 2+ people
Make sensible use of available space
Instructions should be clear with examples if appropriate
A clear title should describe its use
Why code data? (3)
Faster to type than full words
Faster for computer to form searches & sorts
Codes are designed to be unique
3 things to consider when designing codes
Should always be the same length
Must be easy to use & remember
Mustn’t be too short
2 problems with codes
Remembering what code represents
Staff may require training to use codes
What is a database?
2 examples
Colletcion of information
Pupil details in a school
Product details for a business
5 problems with databases on paper
Vast amounts of paper needed
Only 1 person at a time can use each document
Documents can get lost
Searching takes a long time
Gathering info from different docs takes ages
4 advantages with computer databases
Large amounts of data stored in a small space
Can search quickly
Less likely to be lost
More than 1 user can see data at 1 time
4 disadvantages with computer databases
Expensive to buy & install equipment
Collecting & setting up expensive
Staff need to be trained
If system fails you can’t access information
What do databases contain?
Records, divided into fields.
Data types? (4)
Text
Number
Date/time
Currency
Yes/No
AutoNumber
What does text consist of?
What is AutoNumber?
Letters, symbols & numbers (Alphanumeric)
Unique value generated by access for each different record
What is a primary key?
Unique value in each record
What is a datafile?
Example?
Collection of related records stored in table with field headings
Participant File
What is a record?
Example?
All the data connected with 1 item organised under field headings
Michael Alexander
What is a field?
Example?
The column which holds the data
Surname
What is a key field?
Example?
A field that uniquely identifies 1 record in a datafile/table
00053
What is a flat file?
Example?
Database containing 1 table with all records contained in table under field headings. Contains data separated by commas or tabs such as in a csv file.
Participant File
What is a relational database?
Example?
A database made up of a group of linked tables
Participants & Trainers
What is a data redundancy?
Data unnecessarily duplicated
What is data integrity?
Accurate, up-to-date data
What is a link field?
A field in 2 tables
What is an optical mark reader?
Optical Mark Reader
Detect pencil mark by reflecting light on it
Advantages of optical mark readers (3)
Fast method for lots of data (10,000 forms per hour)
Only 1 computer needed
More accurate than data being keyed in by a person
Disadvantages of optical mark readers? (3)
If they don’t fill the space or aren’t dark enough, they won’t be read correctly.
Only suitable for recording a selection of answers, not text
Needs answer on identical prepared forms.
What is OCR?
Optical Character Recogition
Scanner & special software.
Scans text.
Writing must be clear
95% accurate
For postcodes at sorting offices
Advantages of optical character recognition (3)
Cheaper
Faster
Can recreate tables & the original layout
Disadvantages of optical character recognition (4)
Not 100% accurate
Documents must be carefully checked & corrected
If it is poor quality writing, more mistakes will be made
Not worth doing for small amounts of text
What does a barcode contain?
Country Code
Manufacturer code
Product code
What is a transcription error?
Any data entry error made when transferring data from one source to another
3 types of transcription error
Omission error
Transposition error
Duplication error
What is an omission error?
Data left out
What is a transposition error?
Characters are swapped by mistake (teh instead of the)
What is a duplication error?
Entering a character twice
What is verification?
Checking data by a person
What is validation?
Checking data by a computer
2 types of data verification
- Double entry - keyed in twice, both versions identical
- Proof reading - read over it - on screen or printout
7 types of data validation
Range check - data falls into a range
Presence check - Ensures fields aren’t blank. (required)
Format check - Must match preset pattern (input mask)
Length check - Data is certain length (length field)
Type check - Number/date field correct type
Lookup tables - right set of values (y or n)
Check digit - added to code to ensure valid (123)
Advantages of databases (5)
Info only stored once
Files can be linked so updates are automatic
Record structure can be altered after being entered
Access is fast using queries
Validation checks can be made easily
Disadvantages of databases (3)
If computer breaks down, can’t access information
Computer files easily copied (protection)
Training needed to use system
What is data compression?
Example?
Advantage?
Disadvantage?
Saves space & reduces download time
Zip file
Easier to send or store (winzip)
Must be decompressed before use
What are bitmapped graphics?
Depend on resolution for quality
What are vector based graphics?
Formed from vector objects i.e. lines
Smaller than bitmaps
What is CSV?
What is RTF?
What is Jpeg?
What if Tiff?
What is Gif?
What is Bmp?
What is pict?
What is txt?
Comma separated variables (text w/ comma btwen items)
Rich Text Format (Text as ASCII files w/ formatting)
Joint Photographic Experts Group (compressed pics)
Tagged Image File Format (Store pics)
Graphics Interchange Format (store bitmap pic)
Bit-mapped (stores pic)
Picture format (Mac pic format)
Text (no format plain text)
What is Doc?
What is pub?
What is Xls?
What is Ppt?
What is Mpeg?
What is Mp3?
What is Mp4?
What is MIDI?
What is Pdf?
What is html?
Document (WORD document)
Publisher (desktop publishing)
Excel file
Powerpoint (presentation package)
Moving Picture Experts Group (Moving pics)
Mpeg3 (Compress sound files)
Mpeg4 (Compress video files)
Musical Instrument Digital Interface
Portable Document Format (Adobe acrobat)
Hypertext Markup Language (web page)
