Connect to Data Lake Relational Engine Using the .NET Driver

The first step is to check if you have the .NET SDK installed and what version it is. Enter the following command:

dotnet --version  

If the dotnet command is not recognized, it means that the .NET SDK has not been installed. If the SDK is installed, the command returns the currently installed version, such as 9.0.101.

If the .NET SDK is not installed, download it from Download .NET and run the installer on Microsoft Windows.

Note: Select the ‘Download .NET SDK x64’ option.

On Linux, follow the instructions for the appropriate Linux version such as Install the .NET SDK or the .NET Runtime on openSUSE.

In order for the shell to recognize that the .NET SDK is installed and for any dotnet commands in future steps to be recognized, a new shell window needs to be opened.

1. Create a new console app with the below commands:

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   cd %HOMEPATH%/DataLakeClientsTutorial
   dotnet new console -o dotNET

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   cd $HOME/DataLakeClientsTutorial
   dotnet new console -o dotNET

2. Open the dotNET.csproj file:

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   cd dotNET
   notepad dotNET.csproj

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   cd dotNET
   pico dotNET.csproj

   Add the following below the PropertyGroup section (within the Project section) to indicate where to load the data lake Relational Engine Client .NET driver from. Modify the HintPath section with the information about where the Sap.Data.SQLAnywhere.Core.v2.1.dll is located on your machine.

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   <ItemGroup>
     <Reference Include="Sap.Data.SQLAnywhere.Core.v2.1">
       <HintPath>C:\SAP\hdlclient\sdk\dotnet\Sap.Data.SQLAnywhere.Core.v2.1.dll</HintPath>
     </Reference>
   </ItemGroup>

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   <ItemGroup>
     <Reference Include="Sap.Data.SQLAnywhere.Core.v2.1">
       <HintPath>/home/dan/sap/hdlclient/sdk/dotnet/Sap.Data.SQLAnywhere.Core.v2.1.dll</HintPath>
     </Reference>
   </ItemGroup>

   

   Once the dotNet.csproj file has been updated, save and close the file.

3. Run the app to validate that data lake driver can be loaded:

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   dotnet run

   If an error occurs, double check that the hintpath is correct and on Linux that the script hdlclienv.sh to set the variables has been run.

   

4. Open an editor to edit the file Program.cs.

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   notepad Program.cs

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   pico Program.cs

5. Replace the entire contents of Program.cs with the code below. Update the host value in the connection string.

   C# Copy

   using System;
   using Sap.Data.SQLAnywhere;
   namespace dotNETQuery
   {
       class Program
       {
           static void Main(string[] args)
           {
               try
               {
                   var connStr = "host=XXXX.iq.hdl.prod-XXXX.hanacloud.ondemand.com:443;UID=USER1;PWD=Password1;ENC=TLS(tls_type=rsa;direct=yes)";
                   using (var conn = new SAConnection(connStr)) {
                       conn.Open();
                       var query = "SELECT TITLE, FIRSTNAME, NAME FROM HOTELS.CUSTOMER";
                       using (var cmd = new SACommand(query, conn)) {
                           using (var reader = cmd.ExecuteReader()) {
                               Console.WriteLine("Query result:");
                               // Print column names
                               var sbCol = new System.Text.StringBuilder();
                               for (var i = 0; i < reader.FieldCount; i++) {
                                   sbCol.Append(reader.GetName(i).PadRight(20));
                               }
                               Console.WriteLine(sbCol.ToString());
                               // Print rows
                               while (reader.Read()) {
                                   var sbRow = new System.Text.StringBuilder();
                                   for (var i = 0; i < reader.FieldCount; i++) {
                                       var value = reader[i].ToString();
                                       if (value != null) {
                                           sbRow.Append(value.PadRight(20));
                                       }
                                   }
                                   Console.WriteLine(sbRow.ToString());
                               }
                               conn.Close();
                           }
                       }
                   }
               }
               catch (Exception ex) {
                   Console.WriteLine("Error - " + ex.Message);
                   Console.WriteLine(ex.ToString());
               }
           }
       }
   }

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   Save and close the Program.cs file after replacing the code.

   The above app makes use of some of the data lake Relational Engine .NET driver methods, such as SAConnection. Connection details for this class can be found at Connection Properties. See also the .NET Driver in the SAP HANA Cloud, data Lake client interfaces guide. Further .NET API details can be found in the .NET API browser.

6. Run the app.

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   dotnet run

   

1. If you have not already done so, download Visual Studio Code.

2. If you have not already done so, in Visual Studio Code, choose File | Add Folder to Workspace, and then add the DataLakeClientsTutorial folder.

   

3. Open the file Program.cs.

   

   Visual Studio Code will recognize the cs file extension and will suggest installing the C# for Visual Studio Code extension. Click Install.

4. Place a breakpoint on the line sbRow.Append line. Select Run | Start Debugging | .NET Core. A configuration will be added. Choose Run | Start Debugging.

   Notice that the debug view becomes active and that the RUN option is .NET Launch.

   Notice that the program stops running at the breakpoint that was set.

   Observe the variable values in the leftmost pane. Step through code.

   

   For further information on debugging .NET apps consult Tutorial: Debug a .NET Core console application using Visual Studio Code and Instructions for setting up the .NET Core debugger.

Congratulations! You have now created and debugged a .NET application that connects to and queries an SAP HANA database.