Section 3 - Consistency

Question 1

Define Consistency

Answer 1

Data consistency is the ability of the data to be read once it has been written

consistency is just simply saying that every client is going
to have the same view of data. - especially important for CosmoDB, a globally distributed service.

Question 2

Define CAP Theorem (2)

Answer 2

• Consistency is just simply saying that every client is going to have the same view of data.
• Availability - every client can always read and write.
• Partition tolerance, which just means the system’s going to work well and it’s going to be available for use.
• CAP theorem is simply: you can pick two of those three things. You can never have all three.
• So you have to choose between consistency (the ability to have the same view of the data), availability (the ability to write and read at the same time), and partition tolerance, which is the availability of the system, basically.