From the course: Java EE: Design Patterns and Architecture
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What is CQRS architecture?
From the course: Java EE: Design Patterns and Architecture
What is CQRS architecture?
- [Instructor] CQRS stands for Command Query Responsibility Segregation. It means that every method in the system should be either a command that performs an action, but cannot return data, or a query that returns data, but must not change any data. It is a principal of imperative computer programming, devised by Bertrand Meyer back in 1988 in his book Object-Oriented Software Construction. Bertrand said there are two types of methods in object-oriented software. The command method, which modifies the application state, but does not return the value, and the query method, which responds to a query with a return value and does not change application state. He proposed that an application should make a separation of command and query methods where possible. However, this is not always desirable. There are occasions where a method must change a state of a system, but also return the value. A typical example that is often cited is that of popping an item from a stack. Calling the pop…
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