What is data consistency in SQL and NoSQL databases?

What is data consistency in SQL and NoSQL databases?

Data consistency refers to the accuracy and reliability of data across databases. In SQL, it often follows ACID properties, ensuring transactions are processed reliably. In NoSQL, consistency can vary, often prioritizing availability and partition tolerance over strict consistency.

Can you explain the ACID properties?

Sure! ACID stands for Atomicity, Consistency, Isolation, and Durability. These properties ensure that database transactions are processed reliably. Atomicity guarantees that all operations in a transaction are completed successfully or none at all. Consistency ensures that a transaction brings the database from one valid state to another. Isolation ensures that transactions do not interfere with each other, and Durability guarantees that once a transaction is committed, it remains so even in the event of a system failure.

How does NoSQL handle data consistency?

NoSQL databases often use eventual consistency, meaning that data will become consistent over time, rather than immediately. This approach allows for higher availability and partition tolerance, which is crucial in distributed systems. Some NoSQL databases also offer tunable consistency levels, allowing developers to choose the balance between consistency and performance.

What are some examples of SQL and NoSQL databases?

Examples of SQL databases include MySQL, PostgreSQL, and Oracle. For NoSQL, you have MongoDB, Cassandra, and Redis. Each has its own use cases and strengths depending on the requirements of the application.