Data Access with ADO.NET

Chapter 10

Data Access with ADO.NET

Three versions of Visual Basic were released before any database access capabilities were provided with the program. Data Access Objects (DAO) technology was added with the release of Visual Basic 3. DAO enabled programmers to access local databases in the Microsoft Jet Database Engine format, which were primarily ISAM (Indexed Sequential Access Method) files. With DAO you could also access databases on a server, but I always found performance between a client and a server to be poor because DAO was optimized for local access.

After DAO came Remote Data Objects (RDO) and then ActiveX Data Objects (ADO). These data access technologies were designed for the client/server paradigm. With the movement away from a client/server model to an n-tier, loosely coupled design, a new data access methodology is required.

ADO.NET components have been designed from the ground up for faster data access and data manipulation in an n-tier environment. Two central components of ADO.NET accomplish this: the in-memory DataSet object and the .NET data provider. The data provider is a set of components that include the Connection, Command, DataReader, and DataAdapter objects. I'll go into more detail about the DataSet object and the data provider objects shortly. First let's see how ADO and ADO.NET compare.