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This article mainly explains "what is the structure of ADO Dataset". Interested friends may wish to take a look. The method introduced in this paper is simple, fast and practical. Now let the editor take you to learn "what is the structure of ADO Dataset"?

You can use a few lines of code to have ADO.NET automatically check the structure of the results, or you can use more code that contains metadata about the structure of the query results.

So why choose an option that requires more code? The main advantage is that it has stronger functionality and better performance. But how does a lot of code make the application run faster? It seems counterintuitive, doesn't it?

Unless you are writing a dedicated query tool, you usually know the structure of the query results in advance. For example, the structure of most ADO DataSet is similar to the following example. Dim rs as Recordset' declares other variables here... Initialize variables and establish a connection to the database:

Rs.Open strSQL, cnDatabase, adOpenStatic, adLockOptimistic, adCmdText Do While Not rs.EOF List1.AddItem rs.Fields ("UserName"). Value rs.MoveNext Loop

In this snippet, the programmer knows that the query contains a column named UserName. The key is that a developer usually knows which columns are returned by the query and what data types are used for those columns. However, ADO does not know the form of the query results in advance. As a result, ADO must query the OLE DB provider, asking questions such as "how many columns are there in the results of the query?"

"," what is the data type of each column in these columns? "," where does the data come from? "and" what is the primary key field of each table referenced in this query? "the OLE DB provider can answer some of these questions, but many times it must call back the database.

In order to get the results of the query and store the data in the DataSet object, the structure of the ADO DataSet needs to know the answers to such questions. You can provide this information yourself, or you can force ADO.NET to get the information from the provider. When you choose to provide your own information, the code runs faster because asking the provider for this information at run time can significantly degrade performance compared to providing metadata through code.

Although writing code to prepare the structure of ADO DataSet can improve the performance of your application, writing code can be tedious. Fortunately, Visual Studio includes design-time data access features that combine the performance of both shows.

For example, you can create a DataSet object based on a query, table name, or stored procedure, and the configuration wizard generates ADO.NET code to run the query and support the submission of updates to the database. Many of these Visual Studio features are discussed in detail in the following sections.

At this point, I believe you have a deeper understanding of "what is the structure of ADO Dataset". You might as well do it in practice. Here is the website, more related content can enter the relevant channels to inquire, follow us, continue to learn!

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