The laptop that was nowhere
A ticket says laptop PC-0472 has a cracked screen. The register has no PC-0472. It has PC-0427.
Two digits were swapped. The ticket goes to the wrong person, and the repair is late. Six checks can stop this kind of fault. This lesson covers all six.
By the end of this lesson
Note
I can name six checks that keep data good and say what each one does.
Key words
| Word | What it means | Example |
|---|---|---|
| Validation | A check that data is sensible and in the right shape. | A tag must be PC- and four digits. |
| Verification | A check that data was copied or typed in correctly. | Type the tag twice. |
| Reliability | Data you can depend on, from a trusted source. | The IT store list |
| Consistency | The same fact matching everywhere it is kept. | One tag, two lists, no difference |
| Integrity | Data that stays complete, correct and properly linked. | A ticket points to a real asset. |
| Redundancy | The same data kept more than once when it is not needed. | The same laptop listed twice |
| Record | One row of data about one thing. | PC-0427, Dell, Room 3 |
The cells students fill in are left blank in this preview.
Starter: what you already know
Have a go
Starter: what you already know
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.
Validation and verification
Validation asks: is this sensible? The computer checks the shape and the range of data as it goes in. A tag with 3 digits is refused.
Verification asks: was this copied correctly? The person types the tag twice, and the computer checks both match. A tag can be valid and still be the wrong tag.
Reliability and consistency
Reliability is about the source. Data from the official asset store is more reliable than a note on a sticky label.
Consistency is about agreement. If two lists hold the same laptop, both must say the same room. When they differ, nobody knows which is right.
Integrity and redundancy
Integrity means data stays complete, correct and linked. A ticket must point to an asset that exists. If the asset is deleted, the ticket has a broken link.
Redundancy is needless repeats. The same laptop listed twice wastes space and can disagree with itself. A planned backup copy is a good copy. A careless duplicate is not.
Check: which method?
Have a go
Check: which method?
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.