Optimistic Locking via Timestamps

Problem

Instead of version numbers, you decide to use an updated_at timestamp for optimistic concurrency control. Write a query to simulate this update: set salary = 85000 for an employee with employee_id = 10 only if their hire_date matches '2005-09-21'.

Database Schema

Table: employees

• employee_id (INT): Unique identifier for the employee.
• first_name (VARCHAR): First name of the employee.
• last_name (VARCHAR): Last name of the employee.
• salary (INT): Employee's salary.
• department_id (INT): Foreign key referencing the department.
• manager_id (INT): Foreign key referencing the manager (another employee).
• hire_date (DATE): Date the employee was hired.

Table: departments

• department_id (INT): Unique identifier for the department.
• department_name (VARCHAR): Name of the department.

Try It

Hint

Solution