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URL: https://www.cdata.com/kb/tech/xml-ado-linqtoef.rst

⇱ LINQ to XML Data


LINQ to XML Data

👁 Jerod Johnson
Jerod Johnson
Director, Technology Evangelism
LINQ offers versatile querying capabilities within the .NET Framework (v3.0+), offering a straightforward method for programmatic data access through CData ADO.NET Data Providers. In this article, we demonstrate the use of LINQ to retrieve information from the XML Data Provider.

This article illustrates using LINQ to access tables within the XML via the CData ADO.NET Data Provider for XML. To achieve this, we will use LINQ to Entity Framework, which facilitates the generation of connections and can be seamlessly employed with any CData ADO.NET Data Providers to access data through LINQ.

See the help documentation for a guide to setting up an EF 6 project to use the provider.

  1. In a new project in Visual Studio, right-click on the project and choose to add a new item. Add an ADO.NET Entity Data Model.
  2. Choose EF Designer from Database and click Next.
  3. Add a new Data Connection, and change your data source type to "CData XML Data Source".
  4. Enter your data source connection information.

    Connecting to Local or Cloud-Stored (Box, Google Drive, Amazon S3, SharePoint) XML Files

    CData Drivers let you work with XML files stored locally and stored in cloud storage services like Box, Amazon S3, Google Drive, or SharePoint, right where they are.

    Setting connection properties for local files

    Set the URI property to local folder path.

    Setting connection properties for files stored in Amazon S3

    To connect to XML file(s) within Amazon S3, set the URI property to the URI of the Bucket and Folder where the intended XML files exist. In addition, at least set these properties:

    • AWSAccessKey: AWS Access Key (username)
    • AWSSecretKey: AWS Secret Key

    Setting connection properties for files stored in Box

    To connect to XML file(s) within Box, set the URI property to the URI of the folder that includes the intended XML file(s). Use the OAuth authentication method to connect to Box.

    Dropbox

    To connect to XML file(s) within Dropbox, set the URI proprerty to the URI of the folder that includes the intended XML file(s). Use the OAuth authentication method to connect to Dropbox. Either User Account or Service Account can be used to authenticate.

    SharePoint Online (SOAP)

    To connect to XML file(s) within SharePoint with SOAP Schema, set the URI proprerty to the URI of the document library that includes the intended XML file. Set User, Password, and StorageBaseURL.

    SharePoint Online REST

    To connect to XML file(s) within SharePoint with REST Schema, set the URI proprerty to the URI of the document library that includes the intended XML file. StorageBaseURL is optional. If not set, the driver will use the root drive. OAuth is used to authenticate.

    Google Drive

    To connect to XML file(s) within Google Drive, set the URI property to the URI of the folder that includes the intended XML file(s). Use the OAuth authentication method to connect and set InitiateOAuth to GETANDREFRESH.

    The property is the controlling property over how your data is represented into tables and toggles the following basic configurations.

    • Document (default): Model a top-level, document view of your XML data. The data provider returns nested elements as aggregates of data.
    • FlattenedDocuments: Implicitly join nested documents and their parents into a single table.
    • Relational: Return individual, related tables from hierarchical data. The tables contain a primary key and a foreign key that links to the parent document.

    See the Modeling XML Data chapter for more information on configuring the relational representation. You will also find the sample data used in the following examples. The data includes entries for people, the cars they own, and various maintenance services performed on those cars.

    Below is a typical connection string:

    URI=C:/people.xml;DataModel=Relational;
  5. 👁 Required connection properties for the data source. (QuickBooks is shown.)
  6. If saving your entity connection to App.Config, set an entity name. In this example we are setting XMLEntities as our entity connection in App.Config.
  7. Enter a model name and select any tables or views you would like to include in the model.
👁 The available tables in the underlying data source. (QuickBooks is shown.)

Using the entity you created, you can now perform select , update, delete, and insert commands. For example:

XMLEntities context = new XMLEntities();

var peopleQuery = from people in context.people
 select people;

foreach (var result in peopleQuery) {
 Console.WriteLine("{0} {1} ", result.Id, result.[ personal.name.first ]);
}

See "LINQ and Entity Framework" chapter in the help documentation for example queries of the supported LINQ.

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