The overall task of working with data in an application can be broken down into several top-level processes. For example, before you display data to a user on a form, you must first connect to a data source (possibly a database or a service that provides data), and then fetch the data you want to display. After you bring this data into your application, you may need somewhere to temporarily store it, such as aDataSet orLINQ to SQL object.
Connecting to Data
<!----> To bring data into your application (and send changes back to the data source), some kind of two-way communication needs to be established. This two-way communication is typically handled by the connection of a TableAdapter in applications that use datasets, or the DataContext for applications that use LINQ to SQL. Visual Studio provides several tools to assist in creating connections that can be used by your application.
Connecting to Data in Visual Studio
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Visual Studio provides tools to connect your application to data from many different sources, such as databases, Web services, and objects. Connections to data are created either programmatically (in code), as the result of dropping data objects onto a form or component designer, or through the completion of one of the data wizards.
<!----> If your application uses a disconnected data model you need to temporarily store the data in your application while you work with it. Visual Studio provides tools that help you create the objects that your application uses to temporarily store data: datasets and LINQ to SQL
An application that uses a disconnected data model will typically connect to a database, run a query bringing data into the application, disconnect from the database, and then manipulate the data offline before reconnecting and updating the database.
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发表于 2016-10-30 08:49:21
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