What are databases, and why do they need DBMS and SQL?
Data is our most important resource. We leave it behind every day: when placing an order in an app, requesting directions in a GPS, making a doctor’s appointment, or liking a post. All of these are millions of tiny actions that need to be stored, processed, and quickly retrieved. That’s what databases are for. But for them to run like clockwork, they need order: a system, a language, and rules. In this article, we’ll explore what a database is, why it needs a DBMS, and the magic behind the three letters SQL.
What are databases?
Spreadsheets help bring order to chaos: creating a party guest list, calculating a vacation budget, or choosing a coffee for lunch. But these spreadsheets only work when they’re small in number. When hundreds of thousands of rows accumulate, and the data spans multiple Excel sheets, everything starts to slow down: searching for information is difficult, and analyzing it is nearly impossible.
A database (or DB) is an electronic storage device that organizes information so it can be accessed quickly, conveniently, and securely. Programmers break data into individual tables—for example, by product, order, or customer—and build relationships between them. The result is not just a storage device, but a living structure that can be analyzed, filtered, linked, and updated in seconds.
Imagine a small company launching a food delivery service. To keep everything running smoothly, they need to consider numerous factors: the menu, ingredients, orders, couriers, customers, and payment methods. Initially, the data can be collected in spreadsheets, but after the first few hundred orders, it becomes clear that a system is essential.
Using a database, you can link orders to specific customers, dishes to the required ingredients, and expenses to suppliers. This makes it easier to calculate costs, track inventory, find popular dishes, and quickly process orders. Most importantly, the data becomes more than just a set of numbers, but a system that can be managed efficiently and scalably.
That’s why a database is the foundation for any serious digital project: an online store, a CRM system, a banking application.
Who works with databases?
This isn’t just about IT; they’re found in almost every industry: from online stores to medical clinics, from banks to logistics. They’re handled by a variety of specialists, each with their own area of responsibility.
Developers
Back-end programmers use databases to store and process data in applications. They write code that creates, updates, and deletes records, configures relationships between tables, and ensures that data is processed quickly and without errors.
Data analysts
They focus not just on storing information, but on extracting meaning from it. They create samples, build reports, and discover patterns—all using database queries, most often in SQL. A good analyst knows how to transform raw data into useful business insights.
Database administrators (DBAs)
These are the people who ensure the stable operation of the database: monitoring speed, security, availability, and backups. They configure servers, optimize queries, and protect data from failures and leaks.
Business professionals and managers
Even if they don’t write SQL queries themselves, they need to understand how the data is structured so they can set appropriate tasks for the technical team and make decisions based on reports.
The larger the company, the more people interact with the database—either directly or through an interface. This means a basic understanding of how everything works is no longer an option, but an essential skill for anyone working in a digital environment. These skills can be mastered through courses.
Database properties
To be useful, a database must possess certain properties that make working with data reliable, predictable, and convenient. In professional circles, these properties are described using the ACID concept, which sets the standard of behavior for most database management systems.
Atomicity
Database operations are completed in full or not at all. For example, if a user places an order and something goes wrong during the payment process, the entire process is canceled, and the data doesn’t end up in the database in a “broken” state.
Consistency
After performing any operation, the database remains in a valid state. This means that all relationships, constraints, and rules are preserved, and the database does not turn into a chaotic data set.
Isolation
Even if multiple users access the database simultaneously, each operation is performed as if it were a single operation. This prevents errors during simultaneous access and updates.
Durability/Reliability
Once data is written, it doesn’t disappear. Even if the power goes out or the server crashes, the information remains in the database thanks to backup and logging mechanisms.
Besides ACID, a good database has other qualities:
- Scalability is the ability to grow with your business and process more and more data without losing performance.
- Availability – the database must be available 24/7, especially if the operation of an application or website depends on it.
- Security – access restrictions, encryption, protection against hacking and leaks.
All these properties are important not only for developers and administrators, but also for businesses, because they directly impact stability, speed, and user trust.
Database types
Databases come in many varieties, but four main types are most commonly used. They differ in how they store and process information—like choosing a storage format: boxes, shelves, bundles, or bags.
Relational
The most classic. Data is stored in tables with a clearly defined structure: rows, columns, and keys. These are suitable for systems where precision, order, and relationships between entities are important—for example, customers, orders, and products in an online store.
Examples: PostgreSQL, MySQL, Microsoft SQL Server.
Document-oriented (NoSQL)
Information is stored as documents similar to JSON files. Different fields can be stored for different objects without strict rules. This is well-suited for projects where the data structure changes over time.
Example: MongoDB.
Key-value
The simplest type: each key corresponds to a single value. It works very quickly, especially for storing user sessions, settings, or cache.
Example: Redis, Amazon DynamoDB.
Counts
They are used in situations where it’s important to store not only data but also the relationships between it. For example, in social media (who’s friends with whom), logistics (which route is shortest), or recommendation systems.
Example: Neo4j.
Each type addresses its own specific needs. Some require reliability and accuracy, others flexibility and speed, and others complex relationships. The key is to choose the format that best suits your project.
What is SQL and DBMS?
A database itself is simply a storage device. To work with it, you need a special tool— a DBMS (database management system). It’s like an operating system for a computer: it manages everything that happens within the database, ensuring order, security, access, and the correctness of operations. It’s through the DBMS that developers, analysts, and applications interact with the data.
The most common form of communication with a DBMS is SQL (Structured Query Language). This is a query language that allows you to “talk” to the database: adding records, finding required rows, updating data, or deleting them.
For example:
SELECT * FROM users WHERE city = ‘Dar-es-Salaam’;
This query will return all users from Moscow. SQL-like languages are used by almost all relational databases—PostgreSQL, MySQL, Microsoft SQL Server, and others.
The DBMS provides:
- data storage and structuring
- access by multiple users simultaneously
- protection against failures, losses, and conflicts
- fast and reliable data operations.
SQL is needed for:
- creating tables and relationships between them
- extracting the necessary information
- updating, deleting, and filtering data
- reporting and analytics.
Taken together, the database, DBMS, and SQL are the single mechanism that underlies virtually every modern digital system, from a bank account to a food delivery app.