Cassandra vs Microsoft SQL Server: What are the differences?

Introduction

Cassandra and Microsoft SQL Server are both popular database management systems, but they have key differences in terms of architecture, scalability, query language, and data model.

1. Scalability: One of the major differences is in terms of scalability. Cassandra is designed to be highly scalable and can easily handle huge amounts of data and high write loads. It follows a masterless architecture where all nodes are equal, allowing for horizontal scaling. On the other hand, SQL Server follows a master-slave architecture and is typically limited in scalability compared to Cassandra.

2. Architecture: Cassandra is a distributed database system that is designed to handle big data workloads. It follows a peer-to-peer architecture where data is evenly distributed across multiple nodes. This architecture allows for fault tolerance and high availability. SQL Server, on the other hand, follows a client-server architecture where a central server handles all the database operations.

3. Query Language: Another significant difference lies in the query language used by the two databases. Cassandra uses Cassandra Query Language (CQL), a SQL-like language that is specifically designed for Cassandra. CQL supports a subset of SQL features along with additional features that are specific to Cassandra. SQL Server, on the other hand, uses Transact-SQL (T-SQL), a proprietary SQL dialect developed by Microsoft. T-SQL is a comprehensive SQL language that provides extensive support for storing, retrieving, and manipulating data.

4. Data Model: Cassandra follows a wide-column data model, also known as a columnar or column-family data model. It allows for flexible schema design and supports large, denormalized datasets. SQL Server, on the other hand, follows a relational data model where data is organized into tables with predefined schemas and relationships.

5. Consistency: Consistency is another key difference between Cassandra and SQL Server. Cassandra offers tunable consistency, allowing users to select the consistency level based on their application's requirements. It provides options like eventual consistency, strong consistency, and various levels in between. SQL Server, on the other hand, offers strong consistency by default, ensuring that data consistency is maintained at all times.

6. Support and Community: SQL Server is developed and maintained by Microsoft and has a large user base. It has extensive support and a well-established community, which means users can easily find resources and assistance. Cassandra, on the other hand, is an open-source project maintained by the Apache Software Foundation. It also has a strong community, but the support may not be as extensive as SQL Server.

In summary, Cassandra and SQL Server differ in terms of scalability, architecture, query language, data model, consistency, and support. While Cassandra excels in scalability and flexible data models, SQL Server offers strong consistency and extensive support options.