Command query responsibility segregation (CQRS)

Command query responsibility segregation (CQRS) is a software engineering design pattern to separate the responsibilities of commands and queries. In this context, a command is a system call that persists a change and returns no information. A query is a system call that returns information and persists no changes. In other words, commands are write operations and queries are read operations. CQRS allows different architectures for each type of operation, a commonly desired characteristic in distributed systems.