DTO DAO POCO BO

architecture domain-driven-design design-patterns
user137348 picture user137348 · Jul 30, 2009 · Viewed 8.1k times · Source

Actually i'm pretty confused about this terms and how they relate to each other. A read something about every one of them but i don't uderstant the work flow..

DTO - Data transfer object - object to transport values
BO Business object - object in domain model. object to make Business logic with
POCO - no idea, i've read a definition on wiki but didn't understood anything
DAO - data access object - object to map the DB table ?

Could someone please bring some light into it for me ?

Answer

Paul van Brenk picture Paul van Brenk · Jul 30, 2009
  • DTO: Data Transfer Object, used to transfer data between loosly coupled services
  • POCO: Plain Old Clr Object, normal CLR object doesn't use any attributes or required inheritance to act as a DAO/DTO
  • BO: Business Object, contains business logic, used in the Business Logic part of your solution
  • DAO: Data Access Object, used to transfer data from your database

So a regular workflow would be to request data from a service, which is sent to your app as a DTO, you convert it to a BO to manipulate it and send it back as a DTO or after converting it to a DAO store it in a database.

You use the different object to separate concerns between the 3 types, a BO doesn't need to know whether it's persisted using a database or a service.

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