Is my overview of .Net Data Providers and ADO.Net correct?

Question

Recently I had to type up some documentation on .net data providers and ado.net. I am trying to get feedback on my findings. Please review and provide corrections or opinions.

Summary This is a high level summary of the basic .Net API’s for interacting with a database. As a developer with mainly a Java and PHP background I was unclear about how ADO.Net related to OleDb and I had no idea what was meant by the term “.Net Data Provider”. I created this because the msdn documentation is HEAVILY focused on ADO.Net and does not give a clear picture of how the many namespaces, interfaces, and classes interact.

.Net Data Provider

• http://msdn.microsoft.com/en-us/library/a6cd7c08(v=VS.71).aspx
• A .NET Framework data provider is used for connecting to a database, executing commands, and retrieving results. Those results are either processed directly, or placed in an ADO.NET DataSet.
• What that actually means is that a .Net Data Provider implements the interfaces defined in the System.Data namespace.
• A .Net Data Provider is similar to a JDBC driver in Java

System.Data

• http://msdn.microsoft.com/en-us/library/system.data.aspx This page contains text that makes you believe that ADO.Net is the CORE part of .Net data access, however the reality is that ADO.Net is the highest level of data access and is built upon the .Net Data Providers that implement the interfaces in the System.Data.
• In my opinion it almost seems like microsoft is trying to hide how database connections work, so that users are trapped using controls provided by visual studio. The System.Data namesapce contains Interfaces that need to be defined by ALL .Net Data Providers

System.Data Core Interfaces

• IDbConnection
• IDbCommand
• IDataAdapter
• IDataReader

Examples of System.Data Implementations

• The following namespaces include classes that implement the core “.Net Data Provider” interfaces defined in System.Data
• System.Data.SqlClient
• System.Data.OleDb
• System.Data.Odbc
• IBM.Data.DB2
• ByteFX.Data.MySqlClient

ADO.Net

• http://msdn.microsoft.com/en-us/library/27y4ybxw(v=VS.71).aspx
• ADO.Net is a database query and manipulation API built on top of the basic .Net Data Provider classes. ADO.Net focuses on disconnected, multi-tier database interaction.
• In my opinion the core ADO.Net classes should be in a separate namespace like System.Data.ADO just for the sake of clarity.

ADO.Net Core Classes

• DataSet
• DataTable
• DataColumn
• DataRelation

Answer 1

System.Data is the "package" that contains everything for working with "Data providers" in .NET. It is true that ADO, is one strategy for working with data, but it is the primary strategy in .NET.

ADO is less about specific DB technologies (as it is not necessarily meant to be a database specific technology) and more about data relationships. The terms: Set, Table, Column, Row and Relationship are well understood modeling terms and ADO.NET makes them first class objects in the .NET space.

Data providers provide low-level implementation specific details for supporting the core ADO.NET concepts (tables, rows, etc) and are meant to abstract away the direct implementation details of how to connect to a data provider. For instance, you should be able to, with relatively little effort, swap out a Jet Data provider, with a Oracle Data provider, in terms of DataTables, DataRows, and DataColumns (query details aside) such that your code is minimally impacted by the change. Why is this important? Because it means you can work with non-homogenous data sources with similar command semantics (i.e. you can work with excel spreadsheets and MySql dbs in the same app with the same objects). This makes reuse and repurposing very easy and very straight-forward.

As a general view you can think of the system this way:

1. The .NET Data provider is where you get your data from. You will need to import from System.Data each provider that your app uses
2. The ADO.NET classes are the concepts you will be working with Tables, Rows, Columns, etc. These have nothing to do with queries, indexes, etc. Those are provider details
3. Your app should only rarely (I would say never, but there are always exceptions) need to be aware of the Provider and instead focus on consuming and producing DataSets, DataTables, etc.

Hope that helps.

Answer 2

In reference to:

In my opinion it almost seems like microsoft is trying to hide how database connections work, so that users are trapped using controls provided by visual studio.

The existence of 3rd party providers does not support the idea that MS is trying to "trap" us into anything.

Hiding "how database connections work" is a kind of abstraction, and is not subversive.