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This article shows you the introduction and concept of LINQ to DataSet, which is concise and easy to understand. It will definitely brighten your eyes. I hope you can gain something through the detailed introduction of this article.

Using LINQ to DataSet, you can query data cached in DataSet objects more quickly and easily. Specifically, LINQ to DataSet can simplify queries by enabling developers to write queries using the programming language itself rather than by using a separate query language. This is especially useful for Visual Studio developers who can now take advantage of compile-time syntax checking, static typing, and IntelliSense support provided by Visual Studio in their queries.

LINQ to DataSet can also be used to query data merged from one or more data sources. This enables many scenarios that require flexible representation and processing of data, such as querying locally aggregated data and middle-tier caching in Web applications. Specifically, general reporting, analysis, and business intelligence applications will require this method of operation.

LINQ to DataSet functionality is exposed primarily through extension methods in the DataRowExtensions and DataTableExtensions classes. LINQ to DataSet is generated based on and using the existing ADO.NET 2.0 architecture and cannot be replaced by ADO.NET 2.0 in application code. The existing ADO.NET 2. 0 code will continue to work in LINQ to DataSet applications. The following figure illustrates the relationship between LINQ to DataSet and ADO.NET 2.0 and datastores.

LINQ to DataSet concept

DataSet is one of the more widely used ADO.NET components. It is a key element of the disconnected programming model on which ADO.NET is based and allows you to explicitly cache data from different data sources. At the presentation layer, DataSet is tightly integrated with GUI controls for data binding. On the middle tier, it provides a cache that preserves the shape of data relationships and includes fast and simple queries and hierarchical navigation services. A common technique for reducing the number of requests to a database is to use DataSet for caching in the middle tier. For example, consider a data-driven ASP.NET Web application. In general, most of the application's data does not change frequently and belongs to common data between sessions or users. This data can be stored in the memory of the Web server, which reduces the number of requests to the database and accelerates user interaction. Another useful feature of DataSet is that it allows applications to import a subset of data from one or more data sources into the application space. The application can then manipulate the data in memory while retaining its relational shape.

Although DataSet has outstanding advantages, its query function is also limited. The Select method can be used for filtering and sorting, and the GetChildRows and GetParentRow methods can be used for hierarchical navigation. But for more complex situations, developers must write custom queries. This can make applications slow in performance and difficult to maintain.

Using LINQ to DataSet, you can query data cached in DataSet objects more quickly and easily. These queries are expressed in the programming language itself, not as strings embedded in the application code. This means that developers do not have to learn a separate query language. In addition, LINQ to DataSet makes Visual Studio developers more productive because Visual Studio IDE provides compile-time syntax checking, static typing, and IntelliSense support for LINQ. LINQ to DataSet can also be used to query data merged from one or more data sources. This enables many scenarios that require flexible representation and processing of data. Specifically, general reporting, analysis, and business intelligence applications will require this method of operation.

Use LINQ to DataSet to query datasets

Only after DataSet is populated can you start using LINQ to DataSet to query DataSet objects. There are several ways to load data into DataSet, such as using the DataAdapter class or LINQ to SQL. After you load the data into the DataSet object, you can start querying the data. Using LINQ to DataSet to express queries is similar to using language integrated queries (LINQ) for other LINQ-enabled data sources. LINQ queries can be executed against a single table in DataSet or against multiple tables by using the Join and GroupJoin standard query operators.

Support for LINQ queries on typed and untyped DataSet objects. If the architecture of DataSet is known at application design time, it is recommended that you use typed DataSet. In typed DataSet, tables and rows have typed members for each column, making the query simpler and more readable.

In addition to the standard query operators implemented in System.Core.dll, LINQ to DataSet adds a variety of DataSet-specific extensions to make it easier to query a set of DataRow objects. These DataSet-specific extensions include operators for comparing row sequences and methods for accessing column values of DataRow.

N-tier applications and LINQ to DataSet

N-tier data applications are data-centric applications that are divided into multiple logical layers (or tiers). A typical N-tier application consists of a presentation tier, an intermediate tier, and a data tier. Separating application components into different layers can improve the maintainability and scalability of the application. For more information about N-tier data applications, see N-Tier data applications.

In N-tier applications, DataSet is usually used in the middle tier to cache information from Web applications. The LINQ to DataSet query function is implemented through the extension method, and extends the existing ADO.NET 2.0 DataSet.

The following diagram shows how LINQ to DataSet is relevant to DataSet and adapts to N-tier applications:

The above is an introduction to LINQ to DataSet and what is the concept. Have you learned any knowledge or skills? If you want to learn more skills or enrich your knowledge reserve, you are welcome to follow the industry information channel.

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