Question

Advantages & disadvantages of encoding data?

Answer 1

so that the data entered is secure until it is decoded

Answer 2

Yeah thanks, i know the definition but i can't seem to find the adv & disadv of it. I mean, i know the adv of USING an encoding system is that all items get given a unique code, etc but what are the advantages/disadvantages of encoding data?

Answer 3

Advantages: It's quicker and easier that writing out the full info ex. Green=G. Takes up less space on a website meaning it will also be a faster website. Disadvantage: People can get confused and may not be able to read or understand it ex leaving your site.

I dont know if that is the answer of your question
.

Link: http://wiki.answers.com/Q/What_are_the_advantages_and_disadvantages_of_coding_data_in_a_database#ixzz1YtYtLZwo

Answer 4

I think you can come up with the advantages.

Possible disadvantages:
- higher cost (think large datasets)
- slower processing
- possibly requires special hardware
- if a key is used, loss of the key could mean loss of data

Answer 5

adv. reduction of using large circuits.disadvantage:to remember encoding methods

Answer 6

Encoding Data

In the early days of computing, computers have very little memory space. Even in the 1980's a computer with 32K of RAM was considered to be adequate. So data was often encoded so that it would take up less memory.

At the most basic level, years would be stored as 2 digits and not 4 i.e. 83 not 1983; 64 not 1964. This is one of the problems that lead to the 'millennium bug'.

In other systems shortened codes would be used instead of the full description.
A car manufacturer may use colour codes - DR = Dark red ; AW = Arctic white; DY = desert yellow etc.
A supermarket may encode the suppliers names - Nab = Nabisco ; Uni = Unilever
A traffic survey might use codes for vehicle types - LV - light van; HGV1 = small lorry ;HGV3 =articulated lorry.

The encoding system need to be chosen carefully if there were not to be problems . In systems where problems do occur it is often because the codes are chosen on an ad hoc basis without much thought being given to expansion of the system , error checking and other considerations.

Example
A school has decided to encode the subjects on its database. The system designer decides that the first two letters of each will be sufficient to give each subject a unique code and designs the database around the following codes.
Ma= Maths, En = English ; Hi = History; Ge = Geography; Fr = French; Sp = Spanish; Re = Religious Education; Ph = Physics ; Ch = Chemistry; Bi = Biology.
The system works well and fulfils a number of the basic rules of code design.
 Codes are short
 Codes are of the same length
 All items have a unique code
 Codes should be easy for humans to understand , remember and communicate

Unfortunately the system fails to fulfil another of the most basic rules
 Codes should allow for expansion of the system

As the designer discovered when the school introduced some new subjects. German, Geology and English Literature.

A good coding system will incorporate all of the above rules and will also ensure that:-

 All items can be given a unique code
 Some form of error checking is present - so you cannot put in a code that does not exist.
 An index of codes is produced
 Out of date codes are removed from the system
 Codes are created and issued by one person (department) - this ensures that two items do not have the same code
 The system is flexible enough to allow small changes in the items description.


Encoding Systems
While it is desirable to have letters in codes - this makes the codes more human friendly. In large systems this can cause problems. So we often find that commercial encoding systems are based around number codes. One great advantage of this is that it allows automatic correction by using check digits or some other form of validation. There are many different system but the following are the most common.

1) Sequence codes:- Each item is simply given the next number in a sequence. Examination candidate's numbers are often a form of sequence code.

John Alpha = 1001
Jane Beta = 1002
Claire Delta = 1003 etc.

2. Block codes:- Numbers in a particular sequence are allocated to a particular sequence (range) of items. Some banks use block codes for customer account numbers, dividing up the customers according to where they live.
North East = 1000000 - 1999999
North West = 2000000 - 2999999
Midlands = 3000000 -3999999 etc.

Care does need to be taken that the system has enough unique numbers. Phone companies have been caught out by the recent expansion in phone use and have had to devise complex new codes to deal with all the customers.

3. Descriptive codes:- some codes incorporate some information about the item . For example jeans often have the waist size included in the product code - NB this system uses block codes for products

narrow leg jeans = 4000
Waist 28 = 4028
Waist 30 = 4030
Waist 32 = 4032

4) Hierarchical codes:- These are often used where there is a relation ship between the items and the items are in categories (and sub categories)

Car Body = 1000
Front Wing = 1000.1
Rear Wing = 1000.2
Boot lid = 1000.3
Boot lid spoiler = 1000.3.1
Boot lid spoiler, mount = 1000.3.1.1

The Dewey system found in libraries also uses a form of hierarchical coding

5) Combination codes:- These are the most common, often incorporating many of the systems above. Usually each section of the code give specific details about the item.

Car vehicle identification codes are a typical example:-










Specific encoding systems

Bar Codes
Bar codes are one of the most widely used encoding systems in the world. Originally designed to allow freight operators to track railway wagons, they are most commonly seen in retail environments in the form of UPCs (universal product codes) . Even here many different encodings are available , but in the U.K. the EAN13 (European Article Number 13 digit) EAN8 systems are the most common.

The code numbers are represented by a series of lines (bars) and spaces which can be read automatically by a reader/scanner. The system has reached a high level of sophistication ;the codes can be read at quite some distance (over 30 metres in warehouse environments); they can be read at any angle, even upside down; and perhaps most importantly the encoding includes automatic error checking (validation).

In retail uses each new item is allocated a unique number by a central agency - the European Article Number Association . This is simply a country of origin code followed by a sequence code. The number does not give any specific detail about the product. When the code is read by the scanner at the point of sale (or elsewhere ) this unique number is fed to a database which returns the details of the product e.g. description, weight, price for use by the till/billing system.

While the system does have some draw backs its universality does mean that, for the foreseeable future ,it will remain the standard form of encoding/automatic data capture in a wide variety of applications. These include retailing, membership cards, competitor tracking in athletics, blood banks, libraries, archaeological finds, etc. etc.

ISBN
The International Standard Book Number may be found on almost all books printed throughout the world. In common with the bar code system this is allocated by a central agency and all books, including reprints, have a unique number. The number is, once again, a composite code. The first two digits indicate the publisher e.g. 14 = Penguin; the next set of digits, the number for that book. The final digit in the code is a check digit. This is produced using a mathematical algorithm when the code is allocated . Whenever the code is entered into a computer system, the system recalculates and checks and compares the original check digit with the number produced. If the ISBN has been entered correctly they will be the same. If not the system will produce an error message.

Answer 7

Thanks guys!! This really helped. I'm surprised it was on wikianswers, i tried checking but i found nothing.
@CamiAD I guess TeachICT does help everyone learn how to copy + paste. Thanks anyway. :)