Three-tier systems
The Matangle customer database is a very typical three-tier, CRUD (create, read, update, and delete) type of system. This software architecture pattern has been in use for decades and continues to be popular. These types of systems are very common, and it is quite likely that you will encounter them, either as legacy systems or as new designs.
In this figure, we can see the separation of concerns idea in action:
The three tiers listed as follows show examples of how our organization has chosen to build its system.
