1. Question 1

In the context of a WHERE clause, what is a predicate?

• ✅ A condition that evaluates to true, false, or unknown.

• ❌ A function to aggregate data

• ❌ A command to sort the data

• ❌ A method to join two tables

Explanation:
A predicate is any logical condition used in a WHERE clause to filter rows.

---

2. Question 2

Which function counts rows?

• ❌ SUM()

• ❌ MIN()

• ❌ AVG()

• ✅ COUNT()

Explanation:
COUNT() returns the number of rows that match a condition or exist in a table.

---

3. Question 3

Correct syntax for updating data?

• ❌ UPDATE table_name SET column_name = value

• ❌ INSERT INTO table_name VALUES (…)

• ✅ UPDATE table_name SET column_name = value WHERE condition

• ❌ DELETE FROM table_name WHERE condition

Explanation:
UPDATE must include a WHERE clause to avoid updating all rows unintentionally.

---

4. Question 4

Clause used to filter rows?

• ❌ HAVING

• ❌ GROUP BY

• ❌ ORDER BY

• ✅ WHERE

Explanation:
WHERE filters rows before grouping or ordering.

---

5. Question 5

Purpose of INSERT?

• ❌ Retrieve data

• ✅ Add new rows to a table

• ❌ Update data

• ❌ Delete data

Explanation:
INSERT is used to add new records into a table.

---

6. Question 6

What is a logical backup?

• ✅ A database dump

• ❌ Full copy of disk files

• ❌ Copy of physical data files

• ❌ Exact mirror of server

Explanation:
Logical backups export database objects (tables, schemas, data) in SQL format.

---

7. Question 7

Why are backups important?

• ❌ Speed up queries

• ✅ Allow data restoration after a disaster

• ❌ Improve redundancy

• ❌ Optimize performance

Explanation:
Backups ensure recoverability after failures, corruption, or accidental deletion.

---

8. Question 8

Backup method requiring least storage?

• ✅ Incremental backup

• ❌ Differential backup

• ❌ Full backup

• ❌ Virtual full backup

Explanation:
Incremental only stores changes since the last backup → smallest size.

---

9. Question 9

Main advantage of virtual full backup?

• ❌ Creates mirror copy

• ❌ Requires least storage

• ❌ Uses a database to track backup data (true but not the main advantage)

• ✅ A virtual full backup can perform a full restoration without any missing files.

Explanation:
Virtual full gives the effect of a full backup without duplicating all data.

---

10. Question 10

What is a database role?

• ❌ Type of schema

• ❌ Command to create databases

• ✅ A collection of permissions that can be assigned to users

• ❌ User-specific configuration

Explanation:
Roles simplify permission management by grouping privileges.

---

🧾 Summary Table

---