In ECET 2026 CSE, Database Management Systems (DBMS) is one of the scoring subjects. From this, Attributes and Keys are the most expected concepts. If you understand this topic, you can easily secure 2–3 marks in the exam.
📘 Concept Notes
🔹 Types of Attributes
- Simple Attribute – Cannot be divided further. (e.g., Roll Number)
- Composite Attribute – Can be divided into sub-parts. (e.g., Full Name → First Name + Last Name)
- Single-valued Attribute – Holds only one value for each entity. (e.g., Age)
- Multi-valued Attribute – Can hold multiple values. (e.g., Phone Numbers)
- Derived Attribute – Value derived from other attributes. (e.g., Age from Date of Birth)
- Key Attribute – Used to uniquely identify entities.
🔹 Types of Keys
- Primary Key – Uniquely identifies each record.
- Candidate Key – A set of attributes that can qualify as primary key.
- Super Key – Any attribute(s) that uniquely identifies records.
- Alternate Key – Candidate keys other than the primary key.
- Foreign Key – Attribute in one table that refers to primary key in another table.
- Composite Key – Primary key formed by combining two or more attributes.
⚙️ Formulas
🔟 10 Most Expected MCQs – DBMS Attributes & Keys
Q1. Which attribute can be further divided into sub-attributes?
A) Simple
B) Composite
C) Single-valued
D) Derived
Q2. A student’s “Full Name” (First + Last) is an example of:
A) Simple
B) Composite
C) Multi-valued
D) Derived
Q3. Which attribute can have multiple values?
A) Single-valued
B) Composite
C) Multi-valued
D) Derived
Q4. Age calculated from Date of Birth is:
A) Derived
B) Multi-valued
C) Simple
D) Composite
Q5. Which key uniquely identifies a record in a table?
A) Candidate Key
B) Super Key
C) Primary Key
D) Foreign Key
Q6. Which key refers to the primary key of another table?
A) Alternate Key
B) Composite Key
C) Foreign Key
D) Candidate Key
Q7. Which of the following can be considered as Candidate Keys?
A) Roll Number
B) Email
C) Both A & B
D) None
Q8. A set of attributes that uniquely identify rows is called:
A) Super Key
B) Primary Key
C) Alternate Key
D) Composite Key
Q9. If a table has Roll Number (unique) and Phone Number (unique), then Phone Number is:
A) Primary Key
B) Candidate Key
C) Foreign Key
D) Derived Key
Q10. A Primary Key formed by combining two attributes is called:
A) Composite Key
B) Super Key
C) Foreign Key
D) Alternate Key
✅ Answer Key
| Q.No | Answer |
|---|---|
| Q1 | B |
| Q2 | B |
| Q3 | C |
| Q4 | A |
| Q5 | C |
| Q6 | C |
| Q7 | C |
| Q8 | A |
| Q9 | B |
| Q10 | A |
🧠 Explanations
- Q1 → B: Composite attributes can be divided into sub-attributes.
- Q2 → B: Full Name = First + Last → Composite.
- Q3 → C: Multi-valued attributes hold multiple values.
- Q4 → A: Age is derived from DOB.
- Q5 → C: Primary Key uniquely identifies a record.
- Q6 → C: Foreign Key refers to Primary Key in another table.
- Q7 → C: Roll No & Email can both be Candidate Keys.
- Q8 → A: Super Key uniquely identifies rows.
- Q9 → B: Phone Number can act as a Candidate Key.
- Q10 → A: Composite Key = Combination of two attributes.
🎯 Why Practice Matters
- DBMS Attributes & Keys are asked in every ECET paper.
- Questions are mostly direct and definition-based.
- This topic also helps in SQL queries & Normalization.
💪 Motivation Talk
Small concepts → sure-shot marks 💯
Don’t skip basics, they build strong foundations.
Practice daily, consistency will bring you success 🚀
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