---
parser: v2
author_name: Dan van Leeuwen
author_profile: https://github.com/danielva
auto_validation: true
time: 10
tags: [ tutorial>beginner, software-product-function>sap-hana-cloud--data-lake, software-product>sap-hana-cloud, programming-tool>java]
primary_tag: software-product-function>sap-hana-cloud--data-lake
slug: hana-cloud-dl-clients-jdbc
canonical_url: https://developers.sap.com/tutorials/hana-cloud-dl-clients-jdbc
---

# Connect to Data Lake Relational Engine Using the JDBC Driver

<!-- description --> Create and debug a Java application that connects to the data lake Relational Engine.

## Prerequisites

- You have completed the first tutorial in this group.

## You will learn

- How to create and debug a Java application that connects to and queries a data lake Relational Engine database

## Intro

[Java Database Connectivity](https://en.wikipedia.org/wiki/Java_Database_Connectivity) (JDBC) provides an [API](https://docs.oracle.com/javase/8/docs/technotes/guides/jdbc/) for accessing databases from Java. An application written to the JDBC standard can be ported to other databases. Database vendors provide JDBC drivers for their database products. Further details of the SAP JDBC driver can be found at [JDBC Driver](https://help.sap.com/docs/hana-cloud-data-lake/client-interfaces/jdbc-driver).

---

### Install a JDK

Ensure that you have a Java Development Kit (JDK) installed and make sure it is accessible from your path.

You should already have the SAP Java Virtual Machine (JVM) installed after completing the [SAP HANA Cloud, Data Lake Client Interfaces Overview](https://developers.sap.com/tutorials/hana-cloud-dl-clients-overview.html#f86d9ece-1bd4-4add-81a4-aedc6b290e97) prerequisite tutorial.

If not, you can download an OpenJDK from at [SapMachine](https://sap.github.io/SapMachine/#download).

To verify that the JDK is correctly set up, run the following:

```Shell
java -version
javac -version
```

If these commands fail, ensure that the folder they are located in is included in your path.  

For Linux, the following command will install Java on openSUSE Leap 15.4.

```Shell (Linux)
sudo zypper install java-11-openjdk-devel
```

### The data lake Relational Engine JDBC driver

The data lake Relational Engine JDBC driver is a type 2 driver, which means it has a native (non-Java) component. For additional details see [Type 2 driver – Native-API driver](https://en.wikipedia.org/wiki/JDBC_driver#Type_2_driver_%E2%80%93_Native-API_driver). The driver is located in `%HDL_CLIENT_HOME%\java\sajdbc4.jar` on Microsoft Windows and `$HDL_CLIENT_HOME/java/sajdbc4.jar` on Linux.  The native component is at `%HDL_CLIENT_HOME%\Bin64\dbjdbc17.dll` on Microsoft Windows and `$HDL_CLIENT_HOME\lib64\libdbjdbc17.so` on Linux.

See [data lake Relational Engine JDBC driver](https://help.sap.com/docs/hana-cloud-data-lake/developer-guide-for-data-lake-relational-engine/jdbc-drivers) for additional details.

### Create a Java application that queries data lake Relational Engine

1. The following commands create a folder named `java`, enter the newly created directory, create a file named `JavaQuery.java`, and open the file in notepad.

    >The HOMEPATH environment variable should resolve to your user in your user's folder such as c:\users\dan.  Its value can be seen on Microsoft Windows by entering echo %HOMEPATH% into a shell.

   ```Shell (Microsoft Windows)
   mkdir %HOMEPATH%\DataLakeClientsTutorial\java
   cd %HOMEPATH%\DataLakeClientsTutorial\java
   notepad JavaQuery.java
   ```

   ```Shell (Linux)
   mkdir -p ~/DataLakeClientsTutorial/java
   cd ~/DataLakeClientsTutorial/java
   pico JavaQuery.java
   ```

2. Copy the following code into `JavaQuery.java`. Update the `host` value in the connection string.

   ```Java
   import java.sql.*;
   public class JavaQuery {
       public static void main(String[] argv) {
           Connection connection = null;
           try {
               //Option 1
               connection = DriverManager.getConnection("jdbc:sqlanywhere:uid=USER1;pwd=Password1;Host=XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXX.iq.hdl.trial-XXXX.hanacloud.ondemand.com:443;ENC='TLS{tls_type=rsa;direct=yes}'");

               //Option 2, the connection properties can be loaded from an ODBC datasource.
               //connection = DriverManager.getConnection("jdbc:sqlanywhere:DSN=HC_HDL_Trial;LOG=myLog.log");  
               //The LOG option is helpful when diagnosing connection issues.
           }
           catch (SQLException e) {
               System.err.println("Connection Failed:");
               System.err.println(e);
               return;
           }
           if (connection != null) {
               try {
                   System.out.println("Connection to data lake Relational Engine successful!");
                   Statement stmt = connection.createStatement();
                   ResultSet resultSet = stmt.executeQuery("SELECT TITLE, FIRSTNAME, NAME FROM HOTELS.CUSTOMER;");
                   while (resultSet.next()) {
                       String title = resultSet.getString(1);
                       String firstName = resultSet.getString(2);
                       String lastName = resultSet.getString(3);
                       System.out.println(title + " " + firstName + " " + lastName);
                   }
               }
               catch (SQLException e) {
                   System.err.println("Query failed!");
               }
           }
       }
   }
   ```

3. Save and close `JavaQuery.java`. On Microsoft Windows, ensure that you are using the command prompt to run the following. 

    Compile the `.java` file into a `.class` file using the following command:

   ```Shell (Microsoft Windows)
   javac -cp %HDL_CLIENT_HOME%\Java\sajdbc4.jar;. JavaQuery.java
   ```

   ```Shell (Linux)
   javac -cp $HDL_CLIENT_HOME/java/sajdbc4.jar:. JavaQuery.java
   ```  

4. Run `JavaQuery.class` and indicate where the JDBC driver is located.  

   ```Shell (Microsoft Windows)
   java -classpath %HDL_CLIENT_HOME%\Java\sajdbc4.jar;. JavaQuery
   ```  

   ```Shell (Linux)
   java -classpath $HDL_CLIENT_HOME/java/sajdbc4.jar:. JavaQuery
   ```  

    ![Java query](https://raw.githubusercontent.com/sap-tutorials/Tutorials/master/tutorials/hana-cloud-dl-clients-jdbc/jdbc-query.png)

See [JDBC Program Structure](https://help.sap.com/viewer/a894a54d84f21015b142ffe773888f8c/latest/en-US/3bd5a89b6c5f1014ad1bae9e04645f43.html) for additional details.  

### Debug the application

Visual Studio Code can run and debug a Java application. It is a lightweight but powerful source code editor available on Microsoft Windows, macOS, and Linux.

1. If required, [Download Visual Studio Code](https://code.visualstudio.com/Download).

2. In Visual Studio Code, choose **File | Open Folder** and then add the `DataLakeClientsTutorial` folder.

    ![Workspace](https://raw.githubusercontent.com/sap-tutorials/Tutorials/master/tutorials/hana-cloud-dl-clients-jdbc/workspace.png)

3. Open the file `JavaQuery.java`, and if asked, install the recommended extensions.

    ![Java extensions](https://raw.githubusercontent.com/sap-tutorials/Tutorials/master/tutorials/hana-cloud-dl-clients-jdbc/extensions.png)

4. Once the Java Extension Pack has been installed, expand the Java Project Explorer, and click on the **+** icon to add the JDBC driver as a referenced library.

    ![Referenced libraries](https://raw.githubusercontent.com/sap-tutorials/Tutorials/master/tutorials/hana-cloud-dl-clients-jdbc/ref-libraries.png)

    The JDBC driver is located at `%HDL_CLIENT_HOME%\Java\sajdbc4.jar` on Microsoft Windows and `$HDL_CLIENT_HOME/java/sajdbc4.jar` on Linux.

5. Place a breakpoint and then select **Run | Start Debugging**.  

    Notice that the debug view becomes active.  

    Notice that the program stops running at the breakpoint that was set. Step through the code by pressing F10 and observe the variable values in the variables pane.

    ![Visual Studio Code debugging](https://raw.githubusercontent.com/sap-tutorials/Tutorials/master/tutorials/hana-cloud-dl-clients-jdbc/debugging.png)

### Knowledge check

Congratulations! You have now created and debugged a Java application that connects to and queries a data lake Relational Engine database.

---