Describe the relationship between TEACHER and DEPARTMENT

Question

BlackTom AI · Accepted Answer

The TEACHER table contains a non-nullable foreign key deptnumber pointing to DEPARTMENT, so each teacher record is assigned exactly one department.

1) Relevant concepts: relational schemas use foreign keys to express relationships; cardinality (one, many) and optionality (mandatory vs optional) are read from relationship notation. A single straight bar (|) next to an entity indicates “one and only one”; a crow’s foot indicates “many”; a circle indicates “zero (optional)”.

2) Step-by-step reasoning:
- Inspect the TEACHER entity: it has an attribute deptnumber (not a primary key). That attribute is the FK that references DEPARTMENT.deptnumber.
- The relationship connector shows a single straight line (mandatory one) at the TEACHER end and a crow’s-foot at the DEPARTMENT end. That notation means: from the TEACHER perspective the multiplicity is exactly 1; from the DEPARTMENT perspective multiplicity is many.
- A non-nullable FK plus the mandatory-one notation means a teacher cannot exist without being assigned to a department.

3) Intermediate deduction steps:
- Presence of deptnumber in TEACHER ⇒ TEACHER belongs to some DEPARTMENT.
- Mandatory indicator (no circle) ⇒ deptnumber cannot be null ⇒ that “some” must always exist.
- Crow’s-foot at DEPARTMENT ⇒ a department may relate to many teachers.

4) Why the correct answer is correct:
Because every TEACHER record has a single, required deptnumber FK, the mapping from TEACHER to DEPARTMENT is one-to-one in the sense “one TEACHER → one DEPARTMENT” (and that one is required). Simultaneously the inverse is one-to-many (one department → many teachers), but the question asks the relationship from TEACHER’s perspective, so it is “1 and only 1 Department.”

5) Why other options are incorrect:
- “0 to 1” would allow a teacher to have no department; the FK is mandatory so this is false.
- “1 to Many / 0 to Many / Many” that imply a teacher can link to multiple departments — not possible because TEACHER stores only a single deptnumber.
- Options phrased about “Many Teachers are associated 1 Department” describe the inverse direction (true as a statement about DEPARTMENT), but they do not match the teacher-centric wording required by the question.
- “No relationship” is false because the FK and connecting line explicitly show a relationship.

Conclusion: The correct characterization is “1 Teacher is associated with 1 and only 1 Department,” which matches the provided answer.

Describe the relationship between TEACHER and DEPARTMENTSingle choice

Similar Questions

In ERD, a customer places many orders. What is the word "place" referring to?

Consider the E-R diagram below Which entity or entities will have foreign key(s)?

Examine the ER diagram below. Which one of the statements about this diagram is invalid?

The following is a graphical representation of two entity sets in a system for a building with access controlled entrance. Which of the following statements best describes the relationship between Visitor and Visitor Pass?

Describe the relationship between COURSE and DEPARTMENT

Describe the relationship between Enrolls and COURSE

Describe the relationship between Enrolls and STUDENT

Describe the relationship between COURSE and Enrolls

More Practical Tools for Students Powered by AI Study Helper

Homework AI Solver

Stylized AI Paper Writer

Plagiarism Checker Assistant

Citation AI Academic Writing Tool

In-Class Translation Assistant

AI Note Generator

AI Quiz Answers

Past Exam Questions from University Test Bank

Smart Practice Assistant

Adaptive Practice

Making Your Study Simpler