Phase 1 Checkpoint (15 questions)

15 questions · 22 marks · 40 minutes. Negative marking on MCQ only: −1/3 mark for a wrong 1-mark MCQ, −2/3 for a wrong 2-mark MCQ. No negative marking for MSQ or NAT; MSQ has no partial credit.

Q1 · MCQ · 1 mark(s) — Notation

Which ER symbol represents a multivalued attribute?

1. (A) Dashed ellipse
2. (B) Double ellipse
3. (C) Underlined attribute
4. (D) Double rectangle

Q2 · MCQ · 1 mark(s) — Attributes

A composite attribute is one that:

1. (A) is computed from other attributes
2. (B) is unique for every entity
3. (C) has several values per entity
4. (D) can be divided into meaningful parts

Q3 · MCQ · 1 mark(s) — Keys

Train coaches are numbered C1, C2, … in every train, and each train has a unique train_no. The key of COACH is:

1. (A) train_no
2. (B) (train_no, coach_no)
3. (C) there is none
4. (D) coach_no

Q4 · NAT · 1 mark(s) — Counting

STUDENT has 12 entities, COURSE has 9. What is the maximum size of the ENROLLS relationship set (M:N)?

Numerical answer: ________

Q5 · MCQ · 1 mark(s) — Degree

"A supplier supplies a part to a project" as one relationship has degree:

1. (A) 3
2. (B) 1
3. (C) 2
4. (D) 4

Q6 · MCQ · 2 mark(s) — Ratio

Each citizen has at most one passport and each passport belongs to exactly one citizen. HOLDS(CITIZEN, PASSPORT) is:

1. (A) M:N
2. (B) 1:1 with CITIZEN partial and PASSPORT total
3. (C) 1:N with CITIZEN total
4. (D) 1:1 with both total

Q7 · NAT · 2 mark(s) — Counting

FACULTY has 25 entities, DEPARTMENT has 5. HEADS(FACULTY, DEPARTMENT) is 1:1 and DEPARTMENT participates totally. How many faculty members head no department?

Numerical answer: ________

Q8 · MCQ · 2 mark(s) — (min,max)

WORKS_ON(EMPLOYEE, PROJECT) shows EMPLOYEE (1, 4) and PROJECT (2, N). Which is correct?

1. (A) Each project has at least 2 employees; each employee works on 1 to 4 projects.
2. (B) Some employees work on no project.
3. (C) Each project has at most 4 employees.
4. (D) Each employee works on 2 or more projects.

Q9 · MSQ · 2 mark(s) — Constraints

Which statements are always true?

1. (A) Total participation means the minimum is at least 1.
2. (B) A relationship set never contains the same combination of entities twice.
3. (C) Cardinality ratio limits the maximum number of relationships per entity.
4. (D) A 1:1 relationship must have total participation on both sides.

Q10 · MCQ · 1 mark(s) — Weak entity

Which must hold for every weak entity type?

1. (A) Its partial key is unique across all its entities.
2. (B) Its owner participates totally in the identifying relationship.
3. (C) It has a key attribute of its own.
4. (D) It participates totally in the identifying relationship.

Q11 · MCQ · 1 mark(s) — Notation

A dashed underline on an attribute name marks:

1. (A) a partial key
2. (B) a multivalued attribute
3. (C) a foreign key
4. (D) a derived attribute

Q12 · MCQ · 2 mark(s) — EER

ACCOUNT is specialised into SAVINGS and CURRENT. Every account is exactly one of the two. The constraints are:

1. (A) overlapping, partial
2. (B) overlapping, total
3. (C) disjoint, total
4. (D) disjoint, partial

Q13 · MCQ · 1 mark(s) — EER

A subclass entity has:

1. (A) all superclass attributes and relationships plus local ones
2. (B) a different key from its superclass entity
3. (C) only local attributes
4. (D) no relationships of its own

Q14 · MCQ · 2 mark(s) — Modelling

"Each patient is assigned at most one bed; a bed may be unoccupied; no bed holds two patients." ASSIGNED(PATIENT, BED) is:

1. (A) 1:1, both partial
2. (B) 1:1, PATIENT total
3. (C) 1:N from BED to PATIENT
4. (D) M:N

Q15 · MSQ · 2 mark(s) — Modelling

"Each invoice has line items numbered within it; each line item names one product; a product appears on many line items." Which are correct?

1. (A) PRODUCT must participate totally.
2. (B) LINE_ITEM's key is (invoice_no, line_no).
3. (C) The relationship between LINE_ITEM and PRODUCT is N:1.
4. (D) LINE_ITEM is a weak entity with owner INVOICE.