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Match the business rule to the correct cardinality: Each i…

Match the business rule to the correct cardinality: Each invoice must be linked to exactly one customer. A warehouse may have no shipments yet, but can have many over time. Each employee belongs to one department, and departments must have at least one employee. Options:A. One and only oneB. Zero or manyC. One or many Correct Answers:1 → A (One and only one)2 → B (Zero or many)3 → C (One or many) Explanation:Each describes a classic rule — invoices always need one customer, warehouses may be empty, and departments require at least one employee.

An HR system includes a Departments table and an Employees t…

An HR system includes a Departments table and an Employees table. Each employee record includes a field called DepartmentID that matches an entry in the Departments table. What role does DepartmentID play in the Employees table? Options:A. Primary KeyB. Candidate KeyC. Foreign KeyD. Surrogate Key Correct Answer: C. Foreign Key Explanation:DepartmentID links each employee to a department by referencing the Departments table. It is not unique in the Employees table, so it isn’t a primary or candidate key. Surrogate keys are artificial IDs, not cross-table references.

A subscription service keeps track of customers in a table c…

A subscription service keeps track of customers in a table called Customers. Each row has a unique CustomerID, along with fields like Name, Email, and JoinDate. Which field serves as the primary key in this table? Options:A. NameB. EmailC. CustomerIDD. JoinDate Correct Answer: C. CustomerID Explanation:The primary key must uniquely identify each record. Names and emails can be duplicated, and JoinDate certainly isn’t unique. CustomerID is specifically designed as a unique identifier.