Connect to Impala Data from Blazor Apps

Blazor is a framework for developing modern, client-side web UIs using .NET technology. Instead of coding in JavaScript, developers can use the familiar C# language and .NET libraries to build app UIs.

The CData ADO.NET Provider for Impala can be used with standard ADO.NET interfaces, such as LINQ and Entity Framework, to interact with live Impala data. Since Blazor supports .NET Core, developers can use CData ADO.NET Providers in Blazor apps. In this article, we will guide you to build a simple Blazor app that talks to Impala using standard SQL queries.

Install the CData ADO.NET Provider for Impala

CData ADO.NET Providers allow users to access Impala just like they would access SQL Server, using simple SQL queries.

Install the Impala ADO.NET Data Provider from the CData website or from NuGet. Search NuGet for "Impala ADO.NET Data Provider."

Create a Impala-Connected Blazor App

Start by creating a Blazor project that references the CData ADO.NET Provider for Impala

1. Create a Blazor project on Visual Studio.
2. From the Solution Explorer, right click Dependencies, then click Add Project Reference.
3. In the Reference Manager, click the Browse button, and choose the .dll file of the installed ADO.NET Provider (e.g. System.Data.CData.ApacheImpala.dll, typically located at C:\Program Files\CData\CData ADO.NET Provider for Impala\lib etstandard2.0).

SELECT Impala Data from the Blazor App

1. Open the Index.razor file from the Project page.
2. In a ApacheImpalaConnection object, set the connection string:

   In order to connect to Apache Impala, set the Server, Port, and ProtocolVersion. You may optionally specify a default Database. To connect using alternative methods, such as NOSASL, LDAP, or Kerberos, refer to the online Help documentation.

   For example: Server=127.0.0.1;Port=21050;

3. The code below creates a simple Blazor app for displaying Impala data, using standard SQL to query Impala just like SQL Server.

         @page "/"
         @using System.Data;
         @using System.Data.CData.ApacheImpala;
         
         <h1>Hello, world!</h1>
         
         Welcome to your Data app.
         
         <div class="row">
             <div class="col-12">
         
                 @using (ApacheImpalaConnection connection = new ApacheImpalaConnection(
                   "Server=127.0.0.1;Port=21050;"))
                 {
                     var sql = "SELECT City, CompanyName FROM Customers WHERE Country = 'US'";
                     var results = new DataTable();
         
                     ApacheImpalaDataAdapter dataAdapter = new ApacheImpalaDataAdapter(sql, connection);
                     dataAdapter.Fill(results);
         
                     <table class="table table-bordered">
                         <thead class="thead-light">
                             <tr>
                                 @foreach (DataColumn item in results.Rows[0].Table.Columns)
                                 {
                                     <th scope="col">@item.ColumnName</th>
                                 }
                             </tr>
                         </thead>
                         <tbody>
                             @foreach (DataRow row in results.Rows)
                             {
                                 <tr>
                                     @foreach (var column in row.ItemArray)
                                     {
                                         <td>@column.ToString()</td>
                                     }
                                 </tr>
                             }
                         </tbody>
                     </table>
                 }
             </div>
         </div>
       

4. Rebuild and run the project. The ADO.NET Provider renders Impala data as an HTML table in the Blazor app.

   At this point, you have a Impala-connected Blazor app, capable of working with live Impala data just like you would work with a SQL Server instance. Download a free, 30-day trial and start working with live Impala data in your Blazor apps today.