Connect to Presto 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 Presto can be used with standard ADO.NET interfaces, such as LINQ and Entity Framework, to interact with live Presto 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 Presto using standard SQL queries.

Getting Started

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Install the CData ADO.NET Provider for Presto

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

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

Create a Presto-Connected Blazor App

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

1. Create a Blazor project on Visual Studio.
👁 Create a Blazor app project.

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.Presto.dll, typically located at C:\Program Files\CData\CData ADO.NET Provider for Presto\lib etstandard2.0).
👁 Reference ADO.NET for Presto .dll in the Blazor app.

SELECT Presto Data from the Blazor App

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

   Set the Server and Port connection properties to connect, in addition to any authentication properties that may be required.

   To enable TLS/SSL, set UseSSL to true.

   Authenticating with LDAP

   In order to authenticate with LDAP, set the following connection properties:

   • AuthScheme: Set this to LDAP.
   • User: The username being authenticated with in LDAP.
   • Password: The password associated with the User you are authenticating against LDAP with.

   Authenticating with Kerberos

   In order to authenticate with KERBEROS, set the following connection properties:

   • AuthScheme: Set this to KERBEROS.
   • KerberosKDC: The Kerberos Key Distribution Center (KDC) service used to authenticate the user.
   • KerberosRealm: The Kerberos Realm used to authenticate the user with.
   • KerberosSPN: The Service Principal Name for the Kerberos Domain Controller.
   • KerberosKeytabFile: The Keytab file containing your pairs of Kerberos principals and encrypted keys.
   • User: The user who is authenticating to Kerberos.
   • Password: The password used to authenticate to Kerberos.

   For example: Server=127.0.0.1;Port=8080;

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

    @page "/"
    @using System.Data;
    @using System.Data.CData.Presto;
    
    <h1>Hello, world!</h1>
    
    Welcome to your Data app.
    
    <div class="row">
    <div class="col-12">
    
    @using (PrestoConnection connection = new PrestoConnection(
    "Server=127.0.0.1;Port=8080;"))
    {
    var sql = "SELECT FirstName, LastName FROM Customer WHERE Id = '123456789'";
    var results = new DataTable();
    
    PrestoDataAdapter dataAdapter = new PrestoDataAdapter(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 Presto data as an HTML table in the Blazor app. 👁 Query Presto from Blazor app.
   

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