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This article mainly talks about "what is the collection of ADO.NET objects". Interested friends may wish to take a look. The method introduced in this paper is simple, fast and practical. Let's let the editor take you to learn what is the collection of ADO.NET objects.

If we want to migrate the code, we can import the existing ADO code into the .NET application, thus saving the investment in writing the code. However, without major design adjustments to the ADO.NET object, it is almost impossible to port the same code to ADO.NET. The object models of ADO and ADO.NET are different, and they are completed under different design guidelines.

ADO.NET is only used to construct Web applications based on .NET servers. ADO.NET is the data access API for .NET applications. Therefore, you can not consider ADO.NET until the ADO.NET object upgrades the server to. Net. It doesn't make sense for ADO and ADO.NET to work together in the same application. Although you can use both (at least from a design perspective), it's not a good choice.

DataSet: this object is a collection object, and the ADO.NET object can contain any number of data tables, as well as constraints, indexes, and relationships for all tables. All of this information is in the form of XML, and we can process, traverse, and search any or all of the data. Figure 1 shows the pattern of a typical DataSet object. In this example, the DataSet object contains two tables, one of which is from SQL Server and the other from Oracle, the ADO.NET object. Two tables are connected by a relationship that associates a set of records of the source table with a set of records of the destination table (for example, a master-detail relationship). In addition, an XML table is associated with the Oracle table through an one-to-one (1:1) relationship.

DataTable: this object represents all the tables that can be found in the DataSet object, as shown in figure 2. We access the collection of DataTable through the Tables property. Similarly, all established dataset relationships can be accessed through the Relations property of DataSet. The Xml property contains the raw XML description of the object from which the .NET application can reconstruct the dataset from the XML string.

In the hierarchy of the ADO.NET object model, the DataTable object is the closest to the Recordset object of ADO. Depending on the specific purpose, we can create and use tables within or outside the dataset. In addition, we can execute the command manually-- but we must first define the schema of the table-- or rely on the managed data provider to create and populate the table. The managed provider, Managed Provider, is a new type of data provider that provides direct access to the data source in ADO.NET. This provider encapsulates a data source and returns data through the Microsoft .NET class. Managed providers share the concept of OLE DB, but it is specialized, optimized, and easy to use. )

DataColumn: the table contains information about columns, including column names, types, and attributes. ADO.NET object We can create a DataColumn object, specify the data type, and then add the column to the table as follows:

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