Ch 08: Relationships & Cardinality Constraints

Under standard relational database guidelines, which key or column classification is strictly used to guarantee that every individual row (tuple) of a table can be uniquely identified?

TeacherID CHAR(5) PRIMARY KEY

In an SQL table, which of the following schema constraints or columns is strictly designed to uniquely identify individual rows (tuples) of a given table?

stId CHAR(5) PRIMARY KEY

Analyze the following business description: 'A university registration system allows students to enroll in courses. Each student has a unique registration number, name, and email. Each course has a unique course code, title, and credit hours. A student can enroll in multiple courses, and each course can have many registered students.' Identify the core entity types and relationship cardinality that should be modeled in an Entity-Relationship Diagram (ERD).

-- Entity-Relationship Mapping:
-- Student (M) <--- Enroll ---> (N) Course

Under standard database modeling and integrity rules, which of the following statements is strictly correct regarding Entity Integrity constraints?

-- Entity Integrity Violation Example:
INSERT INTO STUDENT (stId, stName) VALUES (NULL, 'Ali'); -- Fails because stId is Primary Key