Databases explained simply: Everything you need to know about structure, types and use
05 min
eologyeo:magazineDatabases explained simply: Everything you need to know about structure, types and use
A database is the foundation for efficiently storing, managing, and analyzing data. Whether you want to organize customer data, store transactions, or evaluate business figures, none of this would be possible without databases, as they are the backbone of numerous applications.
A database is a structured collection of data organized in such a way that it can be efficiently stored, managed, and retrieved. Databases can contain all kinds of data, from simple lists to complex information models.
A simple example is an address book: it stores names, addresses, and phone numbers in a structured form so that the data can be easily found and sorted.
What are databases used for?
Databases are used wherever large amounts of information need to be systematically organized and quickly accessible. Examples include:
Companies: Management of customer data, orders, or inventory.
Online platforms: Storage of user profiles, posts, and comments.
Science and research: Analysis of large amounts of data such as genome data or climate data.
Government organizations: Management of citizen data, tax information, and public projects.
With a well-structured database, data can be processed quickly, information can be linked, and analyses can be performed.
How is a database structured?
As you now know, a database is a structured system for storing, managing, and querying data. The structure of a database comprises various components that must work together to organize your data efficiently and make it accessible to you.
Figure 1: Components of a database Source: eology
What types of databases are there?
Databases perform different tasks depending on their type and are used in specific scenarios. The choice depends on how data is to be organized, processed, and retrieved. Here are the most important database types with their characteristics, examples, and typical use cases:
Database type
Description
Example
Application scenarios
Relational databases
Structure data in tables and use keys to establish relationships between tables.
MySQL, PostgreSQL, SQLite
Customer databases, order and inventory management systems
NoSQL databases
Store data in unstructured or semi-structured formats such as documents, graphs, or key-value pairs.
MongoDB, Redis, Cassandra
Real-time analytics, content management systems, IoT data
Graph databases
Optimized for the representation and analysis of networks and relationships.
Neo4j
Social networks, recommendation algorithms, fraud detection
Cloud databases
Store data in the cloud and enable access from anywhere.
Amazon RDS, Google Cloud Spanner
Global applications, SaaS platforms, remote data access
Time series databases
Specialize in storing time-based data, such as sensor or log data.
InfluxDB, TimescaleDB
IoT measurements, monitoring systems, financial data analysis
These examples show how different database requirements can be and how important it is to choose the right type for the desired application.
What are database normal forms?
Normalizing a database means designing its structure in such a way that redundancies are minimized and dependencies are optimized. There are several normal forms, of which the first three are most commonly used:
Normal form (1NF): Data is organized in tables, and each cell contains only one value.
Normal form (2NF): Each non-key column is completely dependent on the primary key.
Normal form (3NF): No non-key column depends on another non-key column.
Normalization improves data integrity and facilitates maintenance.
How can you create a database?
Creating a database follows a clear process. Each step is an important part of the cycle to ensure a functional and efficient database structure.
Figure 2: Database structure cycle Source: eology
Define tables
The first step in building a database is to define the tables. Here you specify which data is to be stored and how it is logically structured. For example, a table for customers could contain the following attributes: customer number, name, and address. Each table should focus on a specific data category to maintain clarity.
Organizing columns
In the next step, you define the columns (also called attributes) of the tables. Each column contains a specific type of data, such as names or numbers. The data type for each column is also specified (e.g., text, number, date) to ensure that the data is stored correctly.
Create indexes
To enable fast access to data, you need to create indexes. They work like an index in a book and ensure that search queries can be executed efficiently. For example, an index can be created for the customer number in a table so that queries such as “Find customer with number 123” can be answered more quickly.
Establishing relationships
This step is crucial so that you can link data between different tables. The relationships are established using keys:
Primary keys uniquely identify records in a table.
Foreign keys refer to primary keys in another table to establish a relationship between the data.
Example: A relationship between a customer table and an order table could be established via the customer number.
Executing queries
Once the structure has been created, your data can be retrieved, added, updated, or deleted using queries. SQL (Structured Query Language) is usually used for this purpose. Queries such as SELECT, INSERT, or DELETE help you work with the stored data.
Repeat cycle
Creating a database is an iterative process. After the initial queries and tests, you can regularly adjust and expand the structure. You can add new tables, relationships, or indexes to adapt the database to changing requirements.
What programming language is used to create databases?
Specialized query languages and supporting programming languages are used to create a database. These tools ensure that your data can be efficiently organized, processed, and managed—from structuring in tables to interacting with complex data models.
1. SQL (Structured Query Language)
SQL is the standard language for creating, editing, and querying databases.
It is used in relational databases such as MySQL, PostgreSQL, Microsoft SQL Server, and Oracle.
Examples:
CREATE TABLE to create a table.
INSERT INTO to add records.
2. Programming languages for database applications
In addition to SQL, developers use general programming languages to create and manage complex database structures. The most important languages are:
Python: With libraries such as SQLAlchemy or Django ORM, ideal for database applications.
Java: Especially for large applications, often in conjunction with JDBC (Java Database Connectivity).
C#: Often used in combination with Entity Framework for .NET applications.
PHP: Widely used in web development for database operations with MySQL.
Ruby: With Ruby on Rails and ActiveRecord for database integration.
3. NoSQL databases and specific APIs
For NoSQL databases such as MongoDB or Firebase, developers use JSON or APIs as well as libraries in Python, Node.js, or Java.
SQL is the most important language for working directly with databases. Programming languages such as Python, Java, or C# are indispensable for creating applications that interact with databases.
What is the difference between a database and a database management system?
When it comes to data management, the terms database system and database management system (DBMS) are often confused. However, they describe different but closely related concepts. While a database system is the combination of a database and the associated management software, the DBMS refers to the software that performs this management. The following table helps you clearly understand the differences between the two and shows the role they play in storing and organizing data.
Aspect
Database
Database management system
Definition
Refers to the entirety of a database and the software that manages it.
The software responsible for organizing, storing, and querying data.
Components
Stored data in tables
Functions as an interface between the database and users/applications.
Task
Entirety that stores, organizes, and makes data accessible.
Management and control of the database and access to the data.
Functions
Includes the storage and structure of the data as well as the software logic.
– Efficient storage and retrieval of data – Access restrictions – Ensuring data consistency – Backup and recovery
Examples
Combination of MySQL database and associated MySQL software
Software alone, e.g., MySQL, PostgreSQL, Microsoft SQL Server
Difference between a database and a database management system
Kathas heart has been beating for marketing since her training as a marketing communications specialist. As part of the eology marketing team, she takes care of the agency's trade fair and event management. Katha also enjoys sharing her accumulated eology knowledge in magazines, blogs and journals.
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