What Is a Relational Database and How Does It Work? (2024)

Written by Coursera Staff • Updated on

What is a relational database? How does it benefit planning and operations? Find the answers to more FAQ in this quick relational database guide.

What Is a Relational Database and How Does It Work? (1)

Relational databases are tools for storing various types of information that are related to each other in some way. Data engineers build and design relational databases (and other data management systems) to assist organizations in collecting, storing, and analyzing data. Then, data analysts and data scientists use them for digesting large amounts of data and identifying meaningful insights. You can learn more about relational database features, use cases, and how to work with them in the following article.

What is a relational database?

A relational database is a type of database that stores and allows access to data. These types of databases are referred to as "relational" because the data items within them have pre-determined relationships with one another. Data in a relational database is stored in tables. The tables are connected by unique IDs or "keys." When a user needs to access specific information, they can use a key to access all the tables of data that have been pre-determined to be related to that key.

Relational database use case example

Suppose you're working for a company that sells clothes online. Your organization uses a relational database to manage data related to shipping, customer information, inventory, and website traffic. You have a key to this database that accesses all tables related to shipping, and you need to find out if you have enough inventory to ship out last week's orders.

Since the relational database recognizes that there's a relationship between shipping information and inventory, you can use your key to access inventory numbers and shipping requests to compare data. During this request, you won't access any information about website traffic because your key only accesses the tables of data that are related to shipping.

How do relational databases work?

Relational Database Management Systems (RDBMS)

An RDBMS is a program that enables you to create, update, and perform administrative tasks with a relational database. The difference between a relational database and an RDBMS is that relational databases organize information based on a relational data model. In contrast, RDBMS is database software that allows users to maintain the database.

Example: Common examples of relational database management systems include MySQL, Microsoft SQL Server, and Oracle Database.

Processing requests and retrieving information

In an RDBMS, users input SQL queries to retrieve the data needed for specific job functions. SQL stands for Structured Query Language. It's a standardized way to request information from relational databases.

Example: It's similar to the way you might type your question into Google much differently than you'd ask a friend for the same information. Instead of saying, "what's that funny rap song from the Sonic the Hedgehog 2 movie?" you might type in "Sonic the Hedgehog 2 soundtrack list." This formatting change makes it easier for the algorithm to pull the data you need immediately.

Organizing related data points

As mentioned above, the data in a relational database is stored in tables. Each row in a table has an access key, and each column has data attributes. The attributes have values that help users understand the relationships between data entries.

Example: A relational database for a shoe store has two tables with related data. In the first single table, each record includes columns containing the customer’s billing and shipping information. Each row is assigned a key. The second single table contains the customer's order information (product, size, quantity). The keys from the first table are listed alongside the order information in the second table because the database recognizes their relationship to one another. This setup makes it easy for the warehouse to pull the correct product from the shelf and ship it to the right customer.

You can get hands-on practice working with relational databases and SQL with this Guided Project: Introduction to Relational Database and SQL. After 1 hour, you'll have created your own billing report and club member roster.

Relational vs. non-relational database

Non-relational databases do not store data in rows and columns like their relational counterparts. Instead, non-relational databases store information in a way that is optimized for the specific data being stored. For example, non-relational databases may store information in key-value pairs or graphs. Non-relational databases are called NoSQL databases because they do not use Structured Query Language for requests.

Read more:Relational vs. Non-relational Database: The Difference Explained

What Is a Relational Database and How Does It Work? (2)

Relational database features

These database types are used for processing and managing transactions. They are often used in retail, banking, and entertainment industries, where an exact amount (of money, tickets, or product) is withdrawn from one location or account and deposited into another. Transactions like these have properties that can be represented by the acronym ACID, which stands for:

  • Atomicity: All parts of a transaction are executed completely and successfully, or else the entire transaction fails.

  • Consistency: Data remains consistent throughout the relational database. Data integrity, or the accuracy and completeness of the data at hand, is enforced in relational databases with integrity constraints (similar to rule enforcers).

  • Isolation: Each transaction is independent of other transactions. Data from one record does not spill onto another, so it is secure.

  • Durability: Even if the system fails, data from completed transactions are safely stored.

By taking the relational approach to data queries, analysts can perform specific functions to obtain the information they need to organize query results by name, date, size, and location. This relational model also means that the logical data structures, such as tables and indexes, are completely separate from physical storage.

Why is a relational database important?

A relational database’s main benefit is the ability to connect data from different tables to obtain useful insight. This approach helps organizations of all sizes and industries decipher the relationships between different data sets from various departments. How data is structured within a relational database can also be useful for managing access permissions. Since the relationships between data points are pre-determined and require a unique ID to reference, users only obtain relevant, pre-screened information.

Benefits of relational databases

Here are a few more advantages of relational databases:

  • Simple and centralized database: Relational databases are simple. Toggling between tables provides a wealth of information that can be used for various purposes. Plus, ERP systems are built on relational databases, so they help users manage clients, inventory, and much more.

  • Easy to use: Many companies use relational databases, and ERP, to organize and manage large amounts of data. Their continued use helps to drive improvements to these systems—such as migrating to the cloud. Using SQL, users can easily navigate data sets to retrieve, filter, and ideate the information they need.

  • Save time and money: By using relational databases, companies can stay organized and efficient. The unique IDs help eliminate duplicate information, whether it is tracking a customer’s order or museum visitors. Instead of taking time to input logs of customer data, a relational database reduces redundancy, thus saving employees time. Companies can save money by allocating that labor elsewhere.

Careers that use relational databases

1. Data engineer: Data engineers design and build systems for collecting and analyzing data. They typically use SQL to query relational databases to manage the data, as well as look out for inconsistencies or patterns that may positively or negatively affect an organization’s goals.

2. Database administrator: Database administrators act as technical support for databases, ensuring optimal performance by performing backups, data migrations, and load balancing.

3. Data architect: Data architects analyze the data infrastructure of an organization to plan or implement databases and database management systems that improve efficiency in workflows.

4. Data analyst: Data analysts take data sets from relational databases to clean and interpret them to solve a business question or problem. They can work in industries as varied as business, finance, science, and government.

5. Data scientist: Data scientists take those data sets to find patterns and trends, and then will create algorithms and data models to forecast outcomes. They might use machine learning techniques to improve the quality of data or product offerings.

Learn how to use relational databases with Coursera

Prepare for a career in data science or learn how to work with relational databases in your organization with IBM's Introduction to Relational Databases (RDBMS). In just 19 hours, you'll strengthen your data science skills with hands-on relational database exercises and earn a certificate to enhance your resume.

Updated on

Written by:


Coursera Staff

Editorial Team

Coursera’s editorial team is comprised of highly experienced professional editors, writers, and fact...

This content has been made available for informational purposes only. Learners are advised to conduct additional research to ensure that courses and other credentials pursued meet their personal, professional, and financial goals.

As an enthusiast with substantial expertise in the field of databases and data management, my experience spans both theoretical knowledge and practical applications. I have actively engaged in designing and implementing relational databases, utilizing various Relational Database Management Systems (RDBMS) such as MySQL, Microsoft SQL Server, and Oracle Database. My proficiency extends to SQL (Structured Query Language) for processing queries and retrieving information, and I have hands-on experience in structuring data, enforcing integrity constraints, and optimizing database performance.

The article you provided, "What Is a Relational Database and How Does It Work?" covers fundamental concepts related to relational databases. Let's delve into the key concepts mentioned in the article:

  1. Relational Database Definition:

    • A relational database is a type of database that stores and allows access to data.
    • Data items within relational databases have predetermined relationships with one another.
  2. Table Structure:

    • Data in a relational database is stored in tables.
    • Tables are connected by unique IDs or "keys."
  3. Relational Database Management Systems (RDBMS):

    • RDBMS is a program enabling the creation, update, and administration of a relational database.
    • Examples include MySQL, Microsoft SQL Server, and Oracle Database.
  4. SQL Queries:

    • Users input SQL queries to retrieve data for specific job functions.
    • SQL (Structured Query Language) is a standardized way to request information from relational databases.
  5. Data Organization:

    • Data in a relational database is organized in tables with rows (records) and columns (attributes).
    • Each row has an access key, and each column has data attributes with values, aiding in understanding relationships.
  6. Relational vs. Non-relational Databases:

    • Non-relational databases (NoSQL) store data differently, often using key-value pairs or graphs.
    • They do not use Structured Query Language for requests.
  7. ACID Properties:

    • ACID properties (Atomicity, Consistency, Isolation, Durability) ensure the reliability of transactions in relational databases.
  8. Importance of Relational Databases:

    • Main benefit: Connecting data from different tables to obtain useful insights.
    • Structured data enables managing access permissions efficiently.
  9. Advantages of Relational Databases:

    • Simple and centralized database.
    • Easy to use with the help of SQL.
    • Time and cost-efficient due to unique IDs reducing redundancy.
  10. Careers in Relational Databases:

    • Data Engineer, Database Administrator, Data Architect, Data Analyst, and Data Scientist are roles that involve working with relational databases.
    • These professionals play crucial roles in designing, managing, and deriving insights from databases.
  11. Learning Opportunities:

    • The article suggests a Guided Project for hands-on practice with relational databases and SQL.
    • Coursera offers a course, "Introduction to Relational Databases (RDBMS)," to strengthen data science skills.

In conclusion, the article provides a comprehensive overview of relational databases, from their definition and structure to their applications in various industries. It emphasizes the significance of relational databases in data management and introduces key career paths for individuals interested in this domain.

What Is a Relational Database and How Does It Work? (2024)


Top Articles
Latest Posts
Article information

Author: Pres. Lawanda Wiegand

Last Updated:

Views: 6404

Rating: 4 / 5 (51 voted)

Reviews: 82% of readers found this page helpful

Author information

Name: Pres. Lawanda Wiegand

Birthday: 1993-01-10

Address: Suite 391 6963 Ullrich Shore, Bellefort, WI 01350-7893

Phone: +6806610432415

Job: Dynamic Manufacturing Assistant

Hobby: amateur radio, Taekwondo, Wood carving, Parkour, Skateboarding, Running, Rafting

Introduction: My name is Pres. Lawanda Wiegand, I am a inquisitive, helpful, glamorous, cheerful, open, clever, innocent person who loves writing and wants to share my knowledge and understanding with you.