When designing a system, choosing the appropriate database is crucial as it directly impacts the system's performance, scalability, and maintenance. Some factors to consider include the data model (relational, NoSQL, etc.), scalability requirements, consistency needs, query patterns, and the skill set of the development team. During system design interviews, candidates may be evaluated based on their ability to justify their choice of database based on these factors.
SQL databases are relational databases that follow the SQL (Structured Query Language) standard for querying and managing data. They offer strong ACID (Atomicity, Consistency, Isolation, Durability) compliance, making them suitable for applications that require transactional integrity and data consistency. However, SQL databases can have limitations in terms of scalability, especially when dealing with large volumes of data or high write throughput. They may also require more upfront planning and schema design compared to NoSQL databases.
Simpler databases, such as some NoSQL databases, often offer faster setup and easier scalability compared to SQL databases. They may have more flexible schemas or schema-less designs, allowing for quicker iterations during development. Additionally, simpler databases can be more suitable for certain use cases, such as real-time analytics or content management systems, where the data structure may evolve over time.