Choosing the right database for your system design is a critical decision that can significantly impact the performance, scalability, and maintenance of your system. In this blog post, we'll explore the key considerations that will help you navigate the complex landscape of database options and make the best decision for your system.
Understand your system's specific needs:
To choose the most suitable database for your system, start by gaining a deep understanding of your system's specific needs and goals. Consider the following factors:
Data Volume: Determine the expected size of your data and how it will grow over time.
Read/Write Operations: Assess the ratio of read-to-write operations in your system.
Response Time: Define the acceptable response time for your application.
Scalability: Anticipate the growth and future scalability needs of your system.
For example, if you are developing a content management system with a massive amount of structured data, a relational database may be a good fit. Conversely, if your system requires high scalability and flexible data models, a NoSQL database could be more suitable.
Evaluate Database Types and their Drawbacks:
Databases are broadly categorized into two types: relational and non-relational. In the following sections, we will delve into a detailed discussion of these two database types.
Relational Database
Relational databases use structured schemas to store data in tables. Each table has unique keys for tuples, and relationships are established using primary and foreign keys. Data is organized in rows (instances) and columns (attributes).
Why Relational Database
Relational databases are favored by software professionals due to their ACID transactions and programming convenience. Key features include flexibility through DDL, reduced redundancy via normalization, concurrency control for consistent data, integration of multiple sources, and backup and disaster recovery mechanisms. Relational databases excel in handling enterprise requirements, enabling the coordination of data interactions and aggregating data. They ensure data consistency, offer convenient backup and restoration, and cloud-based options employ continuous mirroring for enhanced protection. These benefits make relational databases an excellent choice for structured data storage in various software applications.
Drawbacks
Table values in a database are typically simple, while in-memory storage allows for complex structures. To bridge this impedance mismatch, data translation is required to make complex structures compatible with relational databases.
The underlying cost associated with a relational database can be significantly high.
Non-Relational Database
A non-relational database, in contrast to traditional database systems, does not employ the conventional tabular schema of rows and columns. Instead, it stores data in non-tabular form and tends to be more flexible than relational databases.
Why Non-Relational Database
NoSQL databases offer a variety of data models for managing large volumes of semi-structured and unstructured data with low latency. They provide a simple design that eliminates the impedance mismatch of relational databases, supports horizontal scaling across clusters, ensures high availability and disaster recovery, handles unstructured and semi-structured data, and often has cost advantages. NoSQL databases use document, columnar, key-value, and graph models, making them suitable for applications requiring flexibility and scalability, without the constraints of traditional relational databases.
Types of non-relational database
Key-value databases
Key-value databases store data in key-value pairs using hash tables. Keys are unique identifiers, and values can range from simple values to complex objects
One common use case for key-value databases is in session management for web applications, where the session ID serves as the key, and the associated user data is stored as the value.
Document database
A document database stores and retrieves structured documents, in formats such as JSON, using a hierarchical tree structure. It supports varying structures and data, including maps, collections, and scalar values.
A common use case for document databases is in content management systems, where the flexible schema and ability to store diverse document types make it ideal for managing and organizing content in a hierarchical structure.
Graph database
Graph databases store data using a graph structure, with nodes representing entities and edges denoting relationships. It allows storing the data once and then interpreting it differently based on relationships.
One prominent use case for graph databases is in social networks, where the relationships between users, such as friendships or connections, can be efficiently stored and queried using the graph data structure.
Columnar database
Columnar databases store data in columns rather than rows, allowing fast and efficient access to specific columns. They excel in handling aggregation, analytics, and reducing disk I/O and data loading needs.
A common use case for columnar databases is in data analytics and business intelligence applications, where the ability to efficiently query and aggregate large datasets across specific columns leads to improved query performance and faster data analysis.
Drawbacks
Non-Relational databases lack a standardized structure, making porting applications between different NoSQL databases challenging.
Non-Relational databases offer varying products with trade-offs between consistency and availability. Strong data integrity and consistency may be compromised in favor of eventual consistency and availability during failures.
When to use relational vs non-relational:
Relational Database:
When structured data needs to be stored.
When your application requires strong data consistency, atomicity, isolation and durability.
When your application requires strict data integrity constraints.
When the data size is relatively small.
Non-relational Database:
When unstructured or semi-structured data needs to be stored.
When your application's data model evolves frequently or you have varying data structures.
When dealing with large amounts of data.
When there is a need for data serialization and deserialization.
It's important to note that these guidelines are general and not definitive rules. The choice between a relational and non-relational database ultimately depends on your specific use case, data requirements, and the trade-offs you are willing to make.