Relational databases vs non-relational databases
A database is a collection of data stored in an organized format. Database management systems are used to access this data collection from which they can view, edit, and utilize the dataset for their respective tasks. These databases can be stored locally on our machines, on-premise clusters, or in the cloud.
We can further divide databases into two categories: relational and non-relational databases.
Relational databases
A relational database is a database, i.e., a collection of tables that have a relationship between them. This relationship is based on links between different tables created through keys. A primary key is a unique identifier for each row in any table, while a foreign key is a primary key from another table. Using both these keys, we can link different rows from different tables together. This allows us to connect between tables, enabling an organized and optimized experience.
Furthermore, we can use SQL queries to access data in a relational database. An example code is given below.
-- Create the user tableCREATE TABLE user (id INT PRIMARY KEY,username VARCHAR(255),password VARCHAR(255),email VARCHAR(255));-- Insert a user recordINSERT INTO user (id, username, password, email)VALUES (1, 'John Doe', 'password@123', 'nauman@educative.io');-- Retrieve and display data from the user tableSELECT * FROM user;
Here is the breakdown for this code.
Lines 2–7: Creates a database table called
userwith four attributes;idas primary key,username,password, andemail.Lines 10–11: Inserts a record into the table with values matching the field pattern used.
Line 14: Runs a
SELECTcommand that retrieves all records from theusertable.
Non-relational databases
A non-relational database stores its collection of data in a non-tabular format. An example is that data can be stored in document-like data structures. In this, the document is highly detailed, with details from anything useful to identify the document later on. Moreover, storing data without assigning it in a tabular format allows more flexibility in storing and accessing data collections.
Furthermore, we can use
Here is the breakdown for this code:
Command 1: Creates a data storage collection called
user.Command 2: Inserts a record value into the table.
Command 3: Finds all records in the
usertable and returns them in theprettyformat.
Differences
Now that we know what each type of database is, we will look into the differences between both.
Relational Database | Non-relational Database |
Optimized for medium to large data volumes | Optimized for huge data volumes |
Low to medium performance | Quick performance |
High reliability due to ACID compliance | Decent reliability |
Can be complex due to join operations | Low complexities |
Low flexibility due to schema compliance | Extremely flexible |
Data accuracy due to primary and foreign key control | Possibility for data inaccuracy as no primary or foreign key |
Reduces data duplication and redundancy | Allows storage of all kinds of data, even for duplicates |
Simplicity due to English like syntax | More complex coding structure for more information storage |
For Online Transaction Processing (OLTP) systems | For Online Analytical Processing (OLAP) systems and Online Transation Processing (OLTP) systems |
Conclusion
Both databases provide high availability, horizontal and vertical scaling, and a suitable storage platform. Which one we pick depends on our needs. We generally use relational databases when relationships between entities are essential and storing similar data together is insufficient. On the other hand, we use non-relational databases with unstructured big data that need to be processed at high speeds. We can conclude that both database options provide vital uses depending on the user's requirements.
