Parametrized POCO Constructors with the Entity Framework

Question

According to Initial POCO Design 1-Pager

Persistence Ignorance refers to being able to allow the developer to write and test domain objects in a way that is entirely independent of fundamental requirements and assumptions that may be made by the infrastructure service (in this case, the Entity Framework). Such requirements / assumptions may often include:

• The need to implement a specific interface (for e.g., IPOCO)
• Inheritance from a base class
• Providing specific constructors
• Object Instantiation/Construction requirements – use a specific factory for instance**
• The need for metadata or mapping class or property Attributes
• The need to use specific relationship mechanisms

This amounts to being able to use Plain Old CLR Objects (POCO) so that a developer can author their domain objects free of all assumptions and requirements imposed by the framework. Using this approach, once the domain objects are ready to their satisfaction, the developer can use these classes with the Entity Framework in order for relational database access and persistence.

As of right now (CTP5), is there any way at all to reconstitute a poco using a parametrized constructor? If not, it's hard to see how the Entity Framework can be said to offer persistence ignorance.

Answer 1

You can have as many parameterized constructors as you want, so long as the framework has access to a parameter-less one, which is available by default if you you have no constructors, or if you provide one in addition to the parameterized ones you create.