Gain insights into fundamental database concepts, relational databases, and entity-relationship diagrams. Learn about normalization techniques and basics of SQL to enhance database efficiency.

Databases are universal - they underlie the technology you use every day. They're a crucial component of everything from telecommunications systems, banking systems, and video games to just about any other software system that maintains some amount of persistent data.

In this course, you'll learn about the fundamental concepts of databases, why and when they're used, what relational databases are, and entity-relationship diagrams. You will also be exposed to techniques like normalization that help to increase the efficiency of databases. You'll wrap up with a look at the basics of Structured Query Language (SQL). 

After completing this course, you will be able to move onto more advanced courses involving database systems and SQL.

Database Design Fundamentals for Software Engineers

# Problem statement

Write a SQL query to fetch the second-highest salary in the SALARY table.

**HINT**: You will need to nest one query inside another to solve this problem.

# Input

The following tables are available to you as inputs:


**EMPLOYEE Table**

| Emp_Id  |  Full_Name | Joining_Date |
| --- | --- | --- |
| 100    | John Smith | 2019/02/20 |
| 101    | Anthony Williams    | 2019/03/01 |
| 102    | Ethan Carter    | 2019/01/28  |
| 103    | Mathew Mercer    | 2019/04/15    |
| 104    | Nolan North    | 2019/05/19    |
| 105    | Ashley Jenkins  | 2019/09/20    |
| 106    | Amy Madison    |  2019/07/05   |
| 107    | Emily Simpson    |  2019/08/22   |
| 108    | Betty White    |  2019/07/09   |



**SALARY Table**

| Emp_Id    |  Project   |  Salary   |
| --- | --- | --- |
| 100    |  P1   |  20,000   |
| 101    |  P2   |  40,000   |
| 102    |  P3   |  50,000   |
| 103    |  P3   |  50,000   |
| 104    |  P2   |  40,000   |
| 105    |  P4   |  15,000   |
| 106    |  P1   |  20,000   |
| 107    |  P5   |  70,000   |
| 108    |  P5   |  55,000   |

This exercise will test your knowledge of aggregate functions.

Introduction

Fundamental Concepts

Data Modeling

Entity-Relationship Data Model

The Relational Data Model

Functional Dependencies

Normalization

Structured Query Language

Conclusion

Exercise 4

Problem statement