I’ve gone down many paths and created many implementations of repositories on different projects and… I’ve thrown the towel in and given up on it, here’s why. Coding for the exception Do you code for the 1% chance your database is going to change from one technology to another? If you’re thinking about your business’s … Read more
I am finishing up a large project using Laravel 4 and had to answer all of the questions you are asking right now. After reading all of the available Laravel books over at Leanpub, and tons of Googling, I came up with the following structure. One Eloquent Model class per datable table One Repository class … Read more
You are actually right. DbContext is an implementation of the unit of work pattern and IDbSet is an implementation of the repository pattern. Repositories are currently very popular and overused. Everybody use them just because there are dozens of articles about creating repository for entity framework but nobody actually describes challenges related to this decision. … Read more
First of all, there’s no code generation going on, which means: no CGLib, no byte-code generation at all. The fundamental approach is that a JDK proxy instance is created programmatically using Spring’s ProxyFactory API to back the interface and a MethodInterceptor intercepts all calls to the instance and routes the method into the appropriate places: … Read more
Factory: Assembles classes, either by composing a bunch of bits together, or choosing type based on some kind of context Provider: Provider is something microsoft “invented” (basically an abstract factory pattern) that is a way of doing a factory of factories, or having a common factory interface which allows factories to be swappable. It is … Read more
Repository Layer gives you additional level of abstraction over data access. Instead of writing var context = new DatabaseContext(); return CreateObjectQuery<Type>().Where(t => t.ID == param).First(); to get a single item from database, you use repository interface public interface IRepository<T> { IQueryable<T> List(); bool Create(T item); bool Delete(int id); T Get(int id); bool SaveChanges(); } and … Read more
There’s a bit of a confusion here. Repositories access aggregate roots. Aggregate roots are entities. The reason for this is separation of concerns and good layering. This doesn’t make sense on small projects, but if you’re on a large team you want to say, “You access a product through the Product Repository. Product is an … Read more
I thought I’d take a crack at answering my own question. What follows is just one way of solving the issues 1-3 in my original question. Disclaimer: I may not always use the right terms when describing patterns or techniques. Sorry for that. The Goals: Create a complete example of a basic controller for viewing … Read more
DAO is an abstraction of data persistence. Repository is an abstraction of a collection of objects. DAO would be considered closer to the database, often table-centric. Repository would be considered closer to the Domain, dealing only in Aggregate Roots. Repository could be implemented using DAO‘s, but you wouldn’t do the opposite. Also, a Repository is … Read more
In the context of the repository pattern, aggregate roots are the only objects your client code loads from the repository. The repository encapsulates access to child objects – from a caller’s perspective it automatically loads them, either at the same time the root is loaded or when they’re actually needed (as with lazy loading). For … Read more