What is CAP theorem? How is it applicable to NoSQL systems?

CAP theorem is known as Brewer's theorem. According to the CAP theorem, there are limitations for the NoSQL database. Against three guarantees of a database, only two can be achieved — consistency, availability and partition tolerance.

CAP stands for Consistency, Availability and Partition tolerance. The CAP theorem is applied to a distributed system where only two desired characteristics will be delivered out of three. There is a different meaning of all CAP characteristics which are:

• Consistency: There are different nodes connected to the system and under Consistency, every client will see the same data on the same time duration.
• Availability: Even if the nodes are down under availability the client will get data responses for which they have requested.
• Partition tolerance: A communication break in the distributed system is known as Partition where you can experience a temporary connection delay or loss between the nodes.