Information controls
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Information controls
• One of the purposes of the information system is to provide and store
information for future uses of the system.
• The intrusion of an error into this information can be fatal to the
organization.
• This information must be correct, for this it must be checked.
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Information controls
Definitions:
• Control: verification that the characteristics of a piece of information are
in accordance with what they should be.
• Checking information means checking its accuracy and its conformity to
the reality of the organization.
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Main types of controls
• There are two types of controls:
1. Controls relating to the information itself and its characteristics independently
of any other information (Direct Control).
2. Controls determining the accuracy of information in comparison with others
information (indirect control).
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Types of Controls:
1- Direct controls:
Are interested in the information itself without considering others.
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- Presence/Non-Presence Control:
• The existence or not of the information on the medium in which it is to appear
(in the database where it is stored).
It concerns the so-called mandatory information
Example: student file: if name does not exist error.
Example: When lending a book
Check the presence and affiliation of the subscriber.
It must exist in the subscriber file.
Example: When registering a new subscriber
Check for non-presence, it must not already exist in the subscriber file.
- Class Control (Type):
• Verify that the information is written in the appropriate class.
• Check the numerical or alphabetical type of information according to its meaning.
Examples:
• Num tel = 2AB356 erreur
• Zip Code = 16I90 Error because the I character is not a number.
• The error must be reported by the machine.
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- Framing control
• Consists of checking the position of a piece of information in its input area.
• By convention: Digital Right-hand framing 2 3
• Alphabetical framing on the left B F
• Note: This control is usually done automatically by the software.
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- Plausibility check
• Verify whether the information is plausible, i.e.: possible and conceivable
according to its meaning.
• Example: Date of birth 31/15/99 "error", because Month: 1..12
wilaya = (1..58).
This control is often referred to as domain control or value range control.
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2- Indirect controls: compliance of information with others:
- Internal Consistency Control:
• Verify the accuracy of the information part in relation to the other parts of the same
information.
• Example: February 29, 2017 error.
N° Etud: Bi 6 035
With Bi: Biology, Year of Study 6
This is a mistake because the specialisation takes 5 years.
• It is used mainly in the case of articulately coded data.
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- External Consistency Control:
• Verify that information conforms to other information:
Example:
• Year of birth: 2000 / Age: 53 years old error.
• Num: 1 - First name: Mohamed - Date of birth: 1999 - Date of inscription: 1998.
• There is an error in this registration, because date of birth < date of inscription.
• An employee's information. Year of recruitment: 2000, Seniority: 16 years
External consistency check detects an error: Current year 2025, seniority: 25
years
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Indirect controls with calculation
They are carried out by recalculating the value of the information to be checked
Example:
Absences of 1 month = ∑ absences of 4 weeks
Qty in stock = ∑ qty in - ∑ qty out
Order of execution of controls
The checks are run in the following order of citation:
– Attendance control
– Type control
– Framing control
– Plausibility check
– Internal consistency check
– External consistency check
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