Recommended considerations to design **Data Access Layer**

What are the recommended considerations to design Data Access Layer for Enterprise level application. Application built in asp.net 2.0 and N-Hibernate is used in DAL, but there are many flaws in current DAL design and performance and it has been build by other team. We are planning to make new DAL design, so I am looking suggestion from e开发者_Python百科xperts.

Thanks

Asp.net 2.0 and nHibernate scale fine to enterprise level solutions.

It must be something else that is causing the performance problems, it could be:

• Design, structure of database
• Lack of indexes
• Locking, blocking calls
• Insufficient hardware resources
• ...

Martin Fowler (who's considered expert) wrote book titled Patterns of Enterprise Application Architecture, large portion of that book devoted to data access patterns.