🔍 Data Validation & Verification
✅ What is Validation?
Validation is the process of checking whether data entered into a system is reasonable, sensible, and follows predefined rules before processing.
Validation improves data quality but does NOT guarantee real-world correctness.
Example: Age = 150 → rejected, but 25 instead of 26 → accepted.
🔹 Types of Validation
1. Range Check
Ensures values are within limits.Marks: 0–100 | Age: 5–60
2. Format Check
Ensures correct structure.Date: DD/MM/YYYY | Email: user@gmail.com
3. Length Check
Checks number of characters.NIC: 12 characters | Password: min 8 characters
4. Type Check
Ensures correct data type.Age = number, Name = letters only
5. Presence Check
Ensures field is not empty.Username must be filled
6. Check Digit
Extra digit used for error detection.Credit cards, ISBN numbers
7. Consistency Check
Ensures related data matches.Married → Spouse name required
8. Lookup Check
Checks against predefined values.Gender: Male / Female / Other
🎯 Key Points of Validation
✔ Reduces input errors✔ Follows rules and constraints
❌ Does NOT guarantee real-world accuracy
🔍 What is Verification?
Verification is checking whether data is entered correctly by comparing it with the original source.
Methods
✔ Double Entry Verification (entered twice and compared)✔ Visual Check (compare with original document)
🎯 Key Points of Verification
✔ Ensures correct data entry✔ Detects typing mistakes
✔ Improves accuracy
⚖️ Difference Between Validation and Verification
| Feature | Validation | Verification |
|---|---|---|
| Purpose | Check rules and correctness | Check accuracy of entered data |
| When | Before/during entry | After entry |
| Focus | Rules & constraints | Comparison with original data |
| Detects | Invalid data | Human entry errors |
| Result | Accepted or rejected | Correct or incorrect |
Memory Tip:
✔ Validation = “Is it valid?”
✔ Verification = “Is it correct?”
✔ Validation = “Is it valid?”
✔ Verification = “Is it correct?”
🧠 Practice Questions & Answers
1. What is validation?
Checking data rules before entry.
Checking data rules before entry.
2. Does validation ensure accuracy?
No.
No.
3. What is verification?
Checking against original source.
Checking against original source.
4. When is verification done?
After entry.
After entry.
5. Example of range check?
0–100 marks.
0–100 marks.
6. Format check example?
Email format.
Email format.
7. Length check example?
NIC 12 digits.
NIC 12 digits.
8. Type check example?
Numbers only for age.
Numbers only for age.
9. Presence check?
Field must not be empty.
Field must not be empty.
10. Check digit use?
Error detection.
Error detection.
11. Consistency check?
Related fields match.
Related fields match.
12. Lookup check?
Select from list.
Select from list.
13. Double entry verification?
Enter twice and compare.
Enter twice and compare.
14. Visual verification?
Compare with original.
Compare with original.
15. Key difference?
Validation checks rules, verification checks accuracy.
Validation checks rules, verification checks accuracy.
No comments:
Post a Comment