Are there existing data layers I can use for an application I'm building?

Question

I'm writing a .NET application and the thought of implementing a data layer from scratch is icky to me. (By data layer I'm referring to the code that talks to the database, not the layer which abstracts the database access into domain objects [sometimes called the data access layer and used interchangeably with data layer].)

I'd like to find an existing generic data layer implementation which provides standard crud functionality, error handling, connection management - the works. I'll be talking to SQL Server only.

It doesn't matter to me if the library is in C# or VB.NET and I don't care if it's LINQ or ADO.NET. As long as it works.

** I want to emphasize that I'm not looking for data access technologies or mechanisms (e.g. LINQ, ORM tools, etc.) but rather existing libraries.)

Answer 1

Honestly as much of a fan as I've always been with NHibernate. With the latest release of Enterprise Library 5 Data Access Block that they added in the dynamic mapping support natively. I would have to strongly consider not using NHibernate on a project and instead use a forward database generation tool from my domain objects to create my database (perhaps even use NHibernate solely for the scheme export) or something like CodeSmith and use EntLib.

Answer 2

What would you expect this framework to do with your exceptions? If it can't connect to your database, what should it do - crash the application, show an error message (winforms or WPF or ASP)... the questions are endless.

An ORM such as those suggested elsewhere in these answers is likely to be the closest you're going to get. Expecting a third party framework to provide all your exception handling isn't realistic - how would a third party know how your application is supposed to behave?

The direct answer to your question asking for "an existing generic data layer implementation which provides standard crud functionality, error handling, connection management - the works" is simple: use ADO.NET. The answers everyone else have provided actually go beyond that functionality, but your responses suggest that you think that there's something even further beyond - something that implements your data layer for you. My suggestion is that what you're looking for probably doesn't exist.

Answer 3

Microsoft's Entity Framework might be what you are looking for to releave you from writing "the code that talks to the database".

The best things are that it already ships with Visual Studio and - depending on your requirements - you can use most functionality out-of-the box or manually adjust it to your custom business logic via T4 templates.

You can use it for forward and reverse engeneering and being a microsoft technology it integrates well with other MS products like SQL server.

I started using it 3 months ago in my current project at work which is composed of several windows and WCF services to convert third party data into our own database scheme. From the experiences we made with it, we'll be using the EF in future project a lot more.

Answer 4

I'd like to find an existing generic data layer implementation which provides standard crud functionality, error handling, connection management - the works. I'll be talking to SQL Server only.

Might want to check out Subsonic. Though I personally find it quite limited, it's certainly not an ORM, but a "query tool." It will make CRUD operations easy and straightforward, and it generates partial POCO classes for every table in your database, rather than trying to map from a database to a domain layer.

Answer 5

You can use easyobjects has a very small learning curve, and is very extensible. From their web:

EasyObjects.NET is a powerful data-access architecture for the .NET Framework. When used in combination with code generation, you can create, from scratch, a complete data layer for your application in minutes.

Answer 6

If you are talking to only SQL Server the Linq to SQL is your best option. It is pretty easy to get up and running. You will get both the Data Layer and the Abstraction. All you have to do is provide a connection string to Linq to SQL and it will handle the rest.

If you are going to connect to other database than SQL you would want to with NHibernate.

NHibernate takes a little more work than Linq to SQL to get up and running. MS provided in Visual Studio a nice tool that can get you reading from a SQL database pretty quick.