Practice set for DBA Lecture 2. Read the full lesson first: DBMS Architecture and Data Independence Explained on eLecturesAI.
Reading a topic and knowing a topic are two different things. The quickest way to find out which one you have is to answer questions without looking at your notes.
This page has 20 MCQs, 5 short questions and a score guide, all based on DBA Lecture 2: the three levels, schemas, data independence, the DBA view and the parts of a database system.
- Click the option you think is correct. It turns green if you are right and red if you are wrong.
- Read the explanation that opens under the question.
- If you got it wrong, use the Revise link to go back to that exact part of the lesson.
- Check your score at the end and follow the guide.
Section 1: The three levels
Q1How many levels does the DBMS architecture in this lecture describe?
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Answer: C. A database is described at three levels: external, conceptual and internal.
Revise: The three-level architecture
Q2Which level shows what each user or application sees?
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Answer: A. The external level is the user’s view: the part of the data meant for them.
Revise: The three-level architecture
Q3The conceptual level describes:
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Answer: D. The conceptual level is the whole design of the database: all the tables and their relations.
Revise: The three-level architecture
Q4The internal level is concerned with:
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Answer: B. The internal level describes how and where the data is physically stored: files and disks.
Revise: The three-level architecture
Q5In the house example, the architect who holds the plan of the whole house matches which level?
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Answer: C. Guests see the rooms (external), the architect holds the plan (conceptual), and the builder knows the bricks and wiring (internal).
Revise: The three-level architecture
Section 2: Comparing the levels
Q6The description of a level is called a:
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Answer: B. A schema is the description of a level: the external schema, the conceptual schema and the internal schema.
Revise: The three levels compared
Q7“A student sees only their own marks” is an example of which level?
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Answer: A. The external level shows only the part of the data meant for one user.
Revise: The three levels compared
Q8The tables STUDENT, COURSE and RESULT are an example of which level?
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Answer: D. All the tables and the relations between them make up the conceptual level.
Revise: The three levels compared
Section 3: Data independence
Q9What does data independence mean?
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Answer: C. Data independence means a change at one level does not have to break the others. This is why one change does not break everything.
Revise: Data independence
Q10Physical data independence lets you:
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Answer: A. Physical independence is about storage changes. The tables and programs stay the same.
Revise: Data independence
Q11Adding a column to a table without breaking user programs is an example of:
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Answer: D. Changing the table design (the conceptual level) without breaking user programs is logical data independence.
Revise: Data independence
Q12Moving a data file to a new disk is an example of:
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Answer: B. Moving a file changes the internal level, so this is physical independence. Applications do not notice.
Revise: Data independence
Q13In logical independence, which level is changed?
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Answer: A. Logical independence is about changes at the conceptual level, such as adding a column to a table.
Revise: Data independence
Q14Changing the car engine does not change how you drive. Which idea does this example show?
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Answer: C. The engine is the internal part. It changed, but the steering and pedals (the interface) did not. This is physical independence.
Revise: Data independence
Section 4: Why the DBA cares
Q15At which level does most DBA work happen?
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Answer: B. Most DBA work is at the internal level: files, disks and memory. The DBA also manages the conceptual level.
Revise: Why the DBA cares
Q16Views give each user only the data they need. For the DBA, views are mainly a:
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Answer: D. Views belong to the external level, and they let the DBA control what each user can see.
Revise: Why the DBA cares
Q17Because of data independence, the DBA can:
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Answer: A. The DBA can change and tune storage, and the applications keep working as before.
Revise: Why the DBA cares
Section 5: Parts of a database system
Q18Which shows the correct path of a request?
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Answer: C. The user sends a request to the DBMS, the DBMS gets the data from the files, and the answer comes back the same way.
Revise: Parts of a database system
Q19Which part receives the requests, finds the data and applies the rules?
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Answer: A. The DBMS software is the middle part: it receives requests, finds the data and applies the rules.
Revise: Parts of a database system
Q20Oracle is an example of a:
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Answer: B. Oracle is a DBMS, the software that manages databases. We study its internals in Lecture 8.
Revise: Parts of a database system
Short questions (write the answers in your own words)
Don’t just read these. Write each answer on paper in 2-3 lines, then compare.
S1. Name the three levels of a database and say what each one describes.
Show model answer
External: the part of the data that each user or application sees. Conceptual: the whole design, meaning all the tables and the relations between them. Internal: how and where the data is stored, meaning files on disk.
S2. What is a schema?
Show model answer
A schema is the description of a level. There is an external schema, a conceptual schema and an internal schema. A schema describes the structure. It is not the data itself.
S3. Explain physical and logical data independence with one example each.
Show model answer
Physical independence: we can change how data is stored without changing the tables or programs. Example: moving a data file to a new disk. Logical independence: we can change the table design without breaking user programs. Example: adding a column to a table.
S4. Why are views useful to a DBA?
Show model answer
Views belong to the external level. They give each user only the data they need, so they work as a security tool. The DBA can let a student see their own marks without giving access to the whole table.
S5. Name the four parts of a database system and describe the path of a request.
Show model answer
The parts are users, DBMS software, database files and the DBA. A request goes from the user to the DBMS, the DBMS gets the data from the files, and the answer comes back the same way: User, DBMS, Files, and back.
Check your score
Count your correct MCQs (out of 20):
| Score | What it means | What to do next |
|---|---|---|
| 18 – 20 | Excellent. The concepts are solid. | Move on to the next lecture. |
| 14 – 17 | Good, with a few gaps. | Re-read only the sections linked under the questions you missed. |
| 10 – 13 | Half-way there. | Read the lesson again slowly, then retry this quiz tomorrow. |
| Below 10 | The basics are not settled yet. | Read the full lesson once more, draw the three levels from memory, then retake the quiz. |
Go back to the full lesson: DBMS Architecture and Data Independence →
Frequently asked questions
Are these MCQs enough for the exam?
They cover the whole of Lecture 3, but real exams also ask you to write short answers and explain examples. Practice the five short questions above as well.
What is the best way to use an MCQ quiz?
Answer first, check later. Reading the answer without trying the question gives a false feeling of knowing it.
Where do I learn the topic if I got most answers wrong?
Start with the lesson on eLecturesAI: DBMS Architecture and Data Independence Explained. Each question above also links to the exact section to revise.
Written by Engnr.Dr. Muhammad Tahir Dlbar.
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