tailieunhanh - Professional ADO.NET 2 Programming with SQL Server 2005, Oracle and MySQL (P2)

Histor y of Data Access Over the years, many APIs have been released, all of which work toward the goal of providing universal data access. Universal data access is the concept of having a single code base for accessing data from any source, from any language. Having universal data access is important for four reasons: First, developers can easily work on applications targeting different data stores without needing to become experts on each one. Second, developers can have a common framework for data access when switching between programming languages, making the transition to new languages easier. This is especially important in. | History of Data Access Over the years many APIs have been released all of which work toward the goal of providing universal data access. Universal data access is the concept of having a single code base for accessing data from any source from any language. Having universal data access is important for four reasons First developers can easily work on applications targeting different data stores without needing to become experts on each one. Second developers can have a common framework for data access when switching between programming languages making the transition to new languages easier. This is especially important in the .NET Framework in which developers are expected to be able to easily switch between and C . Third it enables developers to more easily write a single application that can be deployed against multiple data stores. Finally it provides a level of abstraction between the application and direct communication to the database to simplify the code the average developer needs to write. Microsoft has conducted surveys to determine which key factors companies are looking for in a data access layer. They came back with four main points which they have tried to implement in their databases and data access components High performance As any developer knows performance can make or break almost any application. No matter how much a data access layer may simplify accessing the data it absolutely must perform nearly as well or better than the alternatives before it becomes a viable solution for the majority of applications. High reliability If a component consumed by an application is buggy or occasionally stops working it is perceived by the users as an error in that application. In addition to being a liability and annoyance to the company that implemented the application it also reflects very poorly on the developer s who wrote the application. Any issues such as memory leaks that cause unreliable results are unacceptable to the development community.