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DataBind Charts to HDFS Data


Use the standard ADO.NET procedures for databinding to provide bidirectional access to HDFS data from controls in the Visual Studio toolbox. This article demonstrates a graphical approach using wizards in Visual Studio, as well as how to databind with only a few lines of code.

DataBinding facilitates two-way interaction with data through UI controls. Using the CData ADO.NET Provider for HDFS streamlines the process of binding HDFS data to Windows Forms and Web controls within Visual Studio. In this article, we will demonstrate using wizards to establish a binding between HDFS data and a chart that dynamically updates. Additionally, the code walk-through section will guide you through the creation of a chart using just 10 lines of code.

DataBind to a Chart

DataBinding consists of three steps: Instantiate the control, configure the data source, and databind.

Configure the Connection and Select Database Objects

To create a chart control and establish a connection to HDFS, follow the steps outlined below using the Data Source Configuration Wizard. Within the wizard, you'll have the option to choose the specific HDFS entities you wish to bind to.

  1. In a Windows Forms project, drag and drop a Chart control from the toolbox to the form. In the Data section of the Chart properties, select DataSource and then select Add Project Data Source from the menu.
  2. In the Data Source Configuration Wizard that appears, select Database -> Dataset.
  3. In the Choose Your Data Connection step, click New Connection.

  4. In the Add Connection dialog, click Change to select the CData HDFS Data Source.

    Below is a typical connection string:

    Host=sandbox-hdp.hortonworks.com;Port=50070;Path=/user/root;User=root;

    In order to authenticate, set the following connection properties:

    • Host: Set this value to the host of your HDFS installation.
    • Port: Set this value to the port of your HDFS installation. Default port: 50070

    When you configure the connection, you may also want to set the Max Rows connection property. This will limit the number of rows returned, which is especially helpful for improving performance when designing reports and visualizations.

  5. Choose the database objects you want to work with. This example uses the Files table.

DataBind

After adding the data source and selecting database objects, you can bind the objects to the chart. This example assigns the x-axis to FileId and the y-axis to ChildrenNum.

  1. In the Chart properties, click the button in the Series property to open the Series Collection Editor.
  2. In the Series properties, select the columns you want for the x- and y-axes: Select columns from the menu in the XValueMember and YValueMember properties.

The chart is now databound to the HDFS data. Run the chart to display the current data.

Code Walk-through

DataBinding to HDFS data requires only a few lines of code and can be completed in three easy steps.

  1. Connect to HDFS.
  2. Create the HDFSDataAdapter to execute the query and create a DataSet to be filled with its results.
  3. DataBind the result set to the chart.

Below is the complete code:

HDFSConnection conn = new HDFSConnection("Host=sandbox-hdp.hortonworks.com;Port=50070;Path=/user/root;User=root;"); HDFSCommand comm = new HDFSCommand("SELECT FileId, ChildrenNum FROM Files WHERE FileId = '119116'", conn); HDFSDataAdapter da = new HDFSDataAdapter(comm); DataSet dataset = new DataSet(); da.Fill(dataset); chart1.DataSource = dataset; chart1.Series[0].XValueMember = "FileId"; chart1.Series[0].YValueMembers = "ChildrenNum"; // Insert code for additional chart formatting here. chart1.DataBind();