This document presents a comprehensive solution to a practical assignment in data modelling and database design, focusing on the creation and manipulation of database tables using SQL. The solution begins by defining three core tables: department, employee, and salary, each with relevant attributes and primary/foreign keys to establish relationships. The assignment then progresses to populate these tables with sample data, including department information, employee details (name, manager ID, job, salary, etc.), and salary levels. A significant portion of the solution involves writing and executing a series of SQL queries to retrieve and modify data within these tables. These queries cover a range of operations, including selecting data, filtering based on conditions (salary ranges, job titles), updating salaries, deleting records, and performing aggregate functions like counting employees and summing salaries per department. Furthermore, the solution includes a guide on how to critique the work, emphasizing normalization, key relationships, data types, and the correct usage of SQL commands. The document concludes with a bibliography of relevant database systems and design resources.
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