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Complete Guide to Database Types: SQL, NoSQL, and more

What is a Database?

A Complete Guide. A database is a storage system that stores data in an organized manner for easy access and management. In just the last two years, 90% of the world’s data has been created, and the volume of global data doubles every two years. All this data is stored in databases.

A database is an organized collection of data managed by a database management system (DBMS). It includes the database, the DBMS, and associated applications. The term “database” is often used loosely to refer to any of these components.

Databases are typically stored on file systems for small datasets. Larger ones reside on computer clusters or cloud storage. Designing databases involves data modeling, efficient storage, query languages, security, privacy, and distributed computing.

 


 

Types of databases

types-database

There are different types of databases. The right database for your organization will be the one that caters to its specific requirements, such as unstructured data management, accommodating large data volumes, fast data retrieval, or better data relationship mapping. Here are some types of databases:

 

Types of Databases:

  1. Data Warehouses
  2. Document-oriented databases
  3. Object-oriented databases
  4. Distributed databases
  5. Network Database
  6. Hierarchical Databases 
  7. SQL databases
  8. NoSQL databases

 

These types of databases are explained below:

 


 

1) Data Warehouses

data warehouse is a type of data management system that is designed to enable and support business intelligence (BI) activities, especially analytics. Data warehouses are solely intended to perform queries and analysis and often contain large amounts of historical data. The data within a data warehouse is usually derived from a wide range of sources such as application log files and transaction applications.

 

Introduction

Key Components

  • Relational database: Stores and manages data.
  • ELT solution: Prepares data for analysis.
  • Analysis tools: Statistical analysis, reporting, data mining.
  • Client analysis tools: Visualizing and presenting data.
  • Advanced applications: Data science, AI algorithms, graphs, and spatial features.

 

Benefits

  • Analysis: Analyzing large amounts of variant data and extracting value.
  • Historical record: Keeping a historical record for analysis.
  • Subject-oriented: Analyzing data about specific subjects or areas.
  • Integrated: Creating consistency among different data types.
  • Nonvolatile: Data remains stable once in the warehouse.
  • Time-variant: Analyzing data over time.
  • Performance: Fast queries, high data throughput, flexibility.
  • Foundation: Serving as the foundation for BI environments.

 

Architecture

  • Simple: Basic design with metadata, summary data, and raw data.
  • Simple with a staging area: Cleaning and processing data before entering the warehouse.
  • Hub and spoke: Adding data marts for customization.
  • Sandboxes: Private areas for exploring new datasets.

 


 

2) Document-oriented databases

A document database (also known as a document-oriented database or a document store) is a database that stores information in documents.

A document-oriented database stores data in flexible, schema-less documents in formats like JSON or BSON. The focus is on storing and querying documents. The documents can vary in structure within the same collection, allowing for easy unstructured or semi-structured data storage.

 

What is a Document Database?

Document databases store data as individual documents, unlike traditional relational databases. Think of these documents as self-contained data entries.

The following is an example of a document that might appear in a document database like MongoDB. This sample document represents a company contact card, describing an employee called Sammy:

Sammy’s contact card document
{
    "_id": "sammyshark",
    "firstName": "Sammy",
    "lastName": "Shark",
    "email": "sammy.shark@digitalocean.com",
    "department": "Finance"
}

 

 JSON 

database-article1

 

All data in JSON documents are represented as field-and-value pairs that take the form of field: value. In the previous example, the first line shows an _id field with the value sammyshark. The example also includes fields for the employees’ first and last names, their email addresses, as well as what department they work in.

 

How do document databases work

 

database-article

 

Advantages

  • Flexibility and adaptability: Easy to change data structure.
  • Handling structured and unstructured data: Can handle both types.
  • Scalability: Can easily scale horizontally to handle large amounts of data.

Disadvantages

  • Handling multiple documents: Can be challenging.
  • Aggregation operations: May not work accurately.

 

Benefits

  • Flexibility and adaptability: Easy to change data structure.
  • Handling structured and unstructured data: Can handle both types.
  • Scalability: Can easily scale horizontally to handle large amounts of data.

 


 

3) Object-oriented databases

Object-oriented databases (OODB) store data as objects and classes, following OOP principles. They were created to connect OOP languages with databases but have limited adoption. However, they offer fast queries and lighter code, which is gaining interest.

 

Building blocks of an object-oriented database

Foundation Elements

  • Objects: Real-world entities with properties (state) and behaviors (methods).
  • Attributes: Properties of an object, such as name, status, and create date.
  • Methods: Actions or functions that modify or operate on object properties.
  • Classes: Groups of objects with the same properties and behaviors.

 

In Conclusion

Object-oriented databases are based on the concepts of objects, attributes, methods, and classes. Understanding these elements is essential for working with OODB.

class task
{
    String name;
    String status;
    Date create_date;

    public void update_task(String status)
    {
    ...
    }
}

Not only do classes indicate relationships, such as parent and child, but they also classify objects in terms of function, data types, or other defined data attributes.

  • Pointers are addresses that facilitate both object access and establishing relationships between objects.

 


 

4) Distributed databases

Since 2020, the amount of data created, captured, copied, and consumed worldwide has almost doubled — that’s an increase of 55.8 zettabytes in just three years!

 

database-article

 

 

 

Advantages

Distributed databases offer reliability, scalability, performance, geographical distribution, and improved resource utilization. They are resilient to failures, can handle increasing data and users, process requests faster, provide better access times, and efficiently use resources.

 

Disadvantages

Distributed databases are more complex to set up and manage. They can have challenges with data consistency, network dependency, security, and cost.

 


 

5) Network Database

A network database is a type of database model that allows more complex relationships between data elements compared to hierarchical databases. In a network database, data is organized in a graph structure, where nodes (also called records) are connected by links (also called sets). This flexible structure enables each record to have multiple parent and child records, allowing for many-to-many relationships.

 

Advantages

 

Disadvantages

 

Use Cases and Applications of Network Databases

 


 

6) Hierarchical Databases 

Hierarchical databases are a type of database model that organizes data in a tree-like structure, where each record has a single parent and potentially many children. This model is akin to a hierarchical organizational chart, where each node (or record) represents an entity and is connected to other nodes in a parent-child relationship. In this structure, data is stored in a series of levels, with the top level being the root, and each subsequent level representing subordinate nodes.

 

Advantages

  • Simplicity: Hierarchical databases are easy to design and understand.
  • Data integrity: They enforce a clear structure and prevent data anomalies.
  • Performance: They excel in applications that naturally fit a tree structure.
  • Ease of management: Managing data is straightforward due to the hierarchical relationships.

 

Disadvantages

  • Lack of flexibility: Limited ability to represent complex relationships.
  • Difficulty with many-to-many relationships: Cannot easily handle complex interconnections.
  • Complex querying: Challenging to retrieve data that is not organized hierarchically.
  • Data redundancy: Potential for data duplication and inconsistencies.
  • Difficulty in handling changes: Difficult to modify or extend the hierarchy.

 


 

7) SQL databases

Key Features of SQL Databases:

 

Common SQL Database Management Systems:

  • MySQL: A popular open-source relational database management system.
  • PostgreSQL: Another open-source relational database known for its advanced features and scalability.
  • Oracle Database: A commercial relational database system widely used in enterprise environments.
  • Microsoft SQL Server: A commercial relational database system from Microsoft.
  • SQLite: A lightweight, embedded SQL database engine often used in mobile applications and small-scale projects.

 

Applications of SQL Databases:

SQL databases are used in a wide range of applications, including:

  • Web Development: Storing and managing data for websites and web applications.
  • Enterprise Applications: Handling large-scale data for business systems and operations.
  • Data Analytics: Analyzing and extracting insights from large datasets.
  • Scientific Research: Storing and managing scientific data.
  • Mobile Apps: Storing data locally on mobile devices.

 

Advantages of SQL

  1. Adaptable: SQL offers flexibility to manage changing data needs.
  2. Reliable Data: Enforces data integrity and consistency.
  3. Powerful Analysis: Provides advanced querying and data analysis options.
  4. Secure Access: Offers robust security features to control data access.
  5. Scalable Performance: Handles increasing data and user loads efficiently.

 

Disadvantages of SQL

  • Complexity: SQL syntax can be difficult to learn and use.
  • Performance: SQL databases can experience performance issues with large datasets or complex queries.
  • Schema Rigidity: Adapting to changes in data structure can be difficult.
  • Maintenance: Managing SQL databases can be resource-intensive.
  • Cost and Limitations: SQL databases can be expensive, may not handle unstructured data well, and can introduce vendor lock-in.

Despite these disadvantages, SQL databases remain widely used due to their robustness, reliability, and comprehensive feature set. However, it’s essential to carefully consider these potential limitations when planning and designing database solutions.

Overall, SQL databases are a versatile and powerful tool for managing and analyzing data in a variety of applications.

 


 

8) NoSQL databases

 

5 types of NoSQL databases

 

How does NoSQL work?

 

Advantages of NoSQL

  • Flexible data model: Accommodates various data formats.
  • Agile development: Supports agile app development.
  • Scalability: Easily increases capacity as needed.
  • Massive data storage: Handles large datasets.
  • High availability: Resistant to outages.
  • Faster queries: Offers faster query performance than relational databases.

 

Disadvantages of NoSQL

  • Immaturity: Relatively new and may lack the maturity of relational databases.
  • Less support: Fewer tools and products, limited developer expertise.
  • Lack of lingua franca: Different query languages and potential incompatibility.
  • Data integrity: This may not offer the same level of data integrity as SQL databases.
  • Complex queries and joins: May struggle with complex queries and joins across multiple nodes.
  • Eventual consistency: This may not be suitable for applications requiring strong global consistency.

 

Overall, NoSQL databases are a good choice for many applications, but it’s important to consider their limitations and choose the right database for your specific needs.

 


 

👉 Explore additional articles for further reading.

 


 

This Post Has 5 Comments

  1. Abbad Muhammad

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  2. Muhammad Sajawal

    Allah bless you with success brother…
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