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This article is to share with you what the concept of ADO.NET is, the editor thinks it is very practical, so I share it with you to learn. I hope you can get something after reading this article. Let's take a look at it with the editor.

The name ADO.NET derives from ADO (ActiveX Data Objects), a broad set of classes used to access data in previous Microsoft technologies. The ADO.NET name is used because Microsoft wants to show that this is the preferred data provider in the .NET programming environment.

I. the role of ADO.NET

It provides platform interoperability and scalable data access. ADO.NET enhances support for connectionless programming mode and supports RICH XML. Because the transmitted data is in XML format, any application that can read XML format can process the data. In fact, the component that accepts the data does not have to be an ADO .NET component, it can be a Microsoft Visual Studio-based solution or any application running on other platforms.

ADO.NET is a set of object-oriented class libraries for interacting with data sources. Typically, the data source is a database, but it can also be a text file, an Excel table, or an XML file.

ADO.NET allows you to interact with different types of data sources and databases. However, there is no series of classes related to this to accomplish such work. Because different data sources use different protocols, the corresponding protocols must be used for different data sources. Some old data sources use the ODBC protocol, many new data sources use the OleDb protocol, and now there are more and more data sources that can be connected through .NET 's ADO.NET class library.

ADO.NET provides public methods for interacting with data sources, but uses a different set of class libraries for different data sources. These class libraries are called Data Providers and are usually named after the type of protocol and data source with which they interact.

2. Classes contained in ADO.NET

1. Connection class

To interact with the database, you must connect to it. The connection help indicates the database server, database name, user name, password, and other parameters required to connect to the database. The Connection object is used by the Command object so that you can know which data source the command is executing on.

The process of interacting with the database means that you must specify the actions you want to perform. This is performed by the Command object. You use the Command object to send SQL statements to the database. The Command object uses a Connection object to indicate which data source to connect to. You can use the Command object alone to execute the command directly, or pass a reference to the Command object to DataAdapter, which holds a set of commands that can manipulate the set of data described below.

2. Command object

After successfully establishing a connection to the data, you can use the Command object to execute commands such as query, modification, insert, delete, and so on; the common methods for Command objects are ExecuteReader method, ExecuteScalar () method, and ExecuteNonQuery () method; insert data can be inserted using the ExecuteNonQuery () method to execute the insert command.

3. DataReader class

Many data operations require you to read only a string of data. The DataReader object allows you to get the results from the SELECT statement of the Command object. For performance reasons, the data returned from DataReader is fast and only a "forward" data stream. This means that you can only pull data from the data stream in a certain order. This is good for speed, but if you need to manipulate data, a better way is to use DataSet.

4. DataSet object

A DataSet object is a representation of data in memory. It includes multiple DataTable objects, while DataTable contains columns and rows, just like a table in a normal database. You can even define relationships between tables to create a master-slave relationship (parent-child relationships). DataSet is used in specific scenarios-- to help manage data in memory and support data disconnect operations. DataSet is the object used by all Data Providers, so it doesn't require a special prefix like Data Provider.

6. DataAdapter class

Sometimes the data you use is mainly read-only, and you rarely need to change it to the underlying data source. Similarly, some situations require caching data in memory to reduce the number of times that unchanged data is called by the database. DataAdapter helps you deal with the above situations easily by disconnecting the model. DataAdapter populates (fill) the DataSet object when continuous changes to read and write operations to the database in a single batch are returned to the database. DataAadapter contains references to connection objects and to automatically open or close connections when reading or writing to a database.

In addition, DataAdapter contains Command object references to SELECT, INSERT, UPDATE, and DELETE operations of the data. You will define a DataAadapter for every Table in DataSet, which will take care of all connections to the database for you. All you will do is tell DataAdapter when to load or write to the database.

7. DataTable class

DataTable is a data grid control. It can be applied to VB and ASP. It can simply bind the database without code. It has a Microsoft-style user interface.

Instantiation of DataTable and addition of columns:

DataTable dt = new DataTable (); dt.Columns.Add ("ID"); dt.Columns.Add ("Name"); DataRow dr = dt.NewRow (); object [] objs = {1, "Name"}; dr.ItemArray = objs; dt.Rows.Add (dr); this.dataGridView1.DataSource = dt

ADO.NET is a. Net technology that interacts with data sources. There are many Data Providers that will allow you to communicate with different data sources-depending on the protocol or database they use. However, no matter what Data Provider you use, you will use similar objects to interact with the data source. The SqlConnection object manages the connection to the data source. The SqlCommand object allows you to communicate with the data source and send commands to it. To quickly read data "forward" only, use SqlDataReader. If you want to use disconnected data, use DataSet and implement SqlDataAdapter that can read or write to the data source.

The above is what the concept of ADO.NET is, and the editor believes that there are some knowledge points that we may see or use in our daily work. I hope you can learn more from this article. For more details, please follow the industry information channel.

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