What is an example of a one-to-many (1:N) relationship?

Question

BlackTom AI · Accepted Answer

One-to-many (1:N) relationships mean a single instance of one entity relates to multiple instances of another entity, while each of those related instances links back to only one instance of the first entity.

1. Relevant concepts
- Entity-Relationship (ER) cardinality: one-to-one (1:1), one-to-many (1:N), many-to-one (N:1), many-to-many (M:N).
- In a 1:N relationship, the “one” side can associate with zero, one, or many records on the “many” side; each “many” record associates with exactly one record on the “one” side.

2. Step-by-step reasoning
- Identify entities and direction: For each answer option determine which entity is on the “one” side and which on the “many” side.
- Check whether a single instance of the first entity can correspond to multiple instances of the second.

3. Application to options (intermediate steps)
- Option: A customer places many orders.
  - Entity A: Customer. Entity B: Order.
  - A single customer can place multiple orders (O1, O2, O3...). Each order is typically placed by one customer. This fits 1 (customer) : N (orders).
- Option: A course can be taught by one professor.
  - That states one course → one professor (1:1) or, interpreted across professors, many courses per professor (N:1). It does not express one-to-many in the course→professor direction.
- Option: An employee works in one department.
  - Many employees can work in the same department (employees:N, department:1) — this is many-to-one, not one-to-many in the stated direction.
- Option: A student enrolled in one course.
  - This phrase implies student → one course (1:1) or many-to-one depending on interpretation; it does not represent one student enrolling in many courses (no 1:N).

4. Why the correct answer is correct
- "A customer places many orders" explicitly describes one customer associated with multiple order records, and each order belonging to a single customer — the textbook definition of a one-to-many (1:N) relationship.

5. Why other options are incorrect
- They describe 1:1 or N:1 relationships or are ambiguous; none explicitly state a single entity instance mapping to multiple instances of another entity as cleanly as the customer/orders example.

Conclusion: The correct answer is "A customer places many orders," which matches the provided answer.

What is an example of a one-to-many (1:N) relationship?单项选择题

类似问题

What shorthand can we use to represent a many-to-many relationship?

Consider the following business rule: 'A professor may advise many students, but each student is assigned to only one advisor.' Which relationship type does this rule establish between the Professor and Student entities?"

Question at position 21 Relational databases establish the relationships between entities by means of common fields included in a file called a(n):relation.entity.relationship.association.

Which of the following is a type of relationship?

The relationship between a Customer and Orders is generally a

Which scenario best represents a one-to-many relationship?

The relationship type that is most supported by any relational databases is:

What command allowed you to add tables in the relationship window?

更多留学生实用工具

智能学习助手

风格化写作助手

论文查重助手

文献引用助手

课堂转译助手

课堂笔记助手

Quiz搜索助手

学校历年真题

智能刷题助手

智能匹配练习

希望你的学习变得更简单