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

# First normal form (1NF)

First normal form (1NF) states that the domain of an attribute must include only **atomic** (simple, indivisible) values and that the value of any attribute in a tuple must be a single value from the domain of that attribute. Hence, 1NF disallows having a set of values, a tuple of values, or a combination of both as an attribute value for a single tuple. The only attribute values permitted by 1NF are single atomic (or indivisible) values. In other words, if a relation contains a multi-valued attribute, it violates 1NF. 

To make things more clear, let's consider the following examples.

## Example 1

**STUDENT Relation**

| Roll_No    |  Name   |  Course   |
| --- | --- | --- |
|  101   |  Micheal   |  Databases, Operating Systems |
| 102    |  Huber   |  Computer Networks, Data Structures   |

The STUDENT relation is not in 1NF because of the multi-valued attribute `Course`. To convert this table into 1NF, we must make sure that the values for the `Course` attribute are atomic. This can be seen below

| Roll_No    |  Name   |  Course   |
| --- | --- | --- |
|  101   |  Micheal   |  Databases |
| 101   |  Micheal   |  Operating Systems |
| 102    |  Huber   |  Computer Networks   |
| 102   |  Huber   |  Data Structures   |

Now this table is in 1NF. 

## Example 2

**STUDENT Relation**

| Roll_No    |  Name   |  Phone   |
| --- | --- | --- |
| 101    |  Felix    |  (123) 456–7890   |
| 102    |  Giorno   |  (456) 686–7821, (789) 316–9880   |
| 103   |  Tom   |  NULL  |

Again we can see that the second student has two phone numbers in a single tuple which violates 1NF. The table can be seen in the first normal form below: 


| Roll_No    |  Name   |  Phone   |
| --- | --- | --- |
| 101    |  Felix    |  (123) 456–7890   |
| 102    |  Giorno   |  (456) 686–7821   |
| 102    |  Giorno   |  (789) 316–9880   |
| 103   |  Tom   |  NULL  |

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In the next lesson, we will look at how the second normal form reduces data redundancy.


In this lesson, we will take a look at first normal form with some examples.

Introduction

Fundamental Concepts

Data Modeling

Entity-Relationship Data Model

The Relational Data Model

Functional Dependencies

Normalization

Structured Query Language

Conclusion

First Normal Form

First normal form (1NF)