Use Smart Data Access to Virtualise Data from the Cloud to an On-Premise Database

1. Start the SAP HANA platform or express edition on-premise or on cloud hypervisor.

2. Login to the tenant database of the on-premise system using the SAP HANA Database Explorer or SAP HANA Studio for the local instance.

3. To create a remote source to SAP HANA Cloud, you need to retrieve some information from the SAP HANA Cloud instance. Both can be found in the SAP HANA Cloud Central:

   • The exact name of your SAP HANA Cloud, SAP HANA database instance
   • The Endpoint of your SAP HANA Cloud, SAP HANA database instance

   

4. Copy the name of the instance and the endpoint and paste it to a text editor.

5. Next, you need to get a certificate string for SAP HANA Cloud, SAP HANA database. In your command line (iTerm or Terminalon iOS, or Command Prompt on WIN) enter this command to download the pem file:

   Shell/Bash Copy

curl -O https://cacerts.digicert.com/DigiCertGlobalRootCA.crt.pem

After the file has been downloaded, use a text editor which can read a `pem` file, such as Notepad or Apple Text Editor, to access the certificate string.




### Create a PSE and a certificate


1.	Create a certificate store, also called PSE (personal security environment). You can read more about [PSE and how to import certificates for SSL connections here](https://help.sap.com/viewer/f9c5015e72e04fffa14d7d4f7267d897/LATEST/en-US/86e96624e9a74e77994f7544db51061c.html).

    ```SQL
CREATE PSE [certificate store name]

2. Create a certificate for SAP HANA Cloud, SAP HANA database and name it, for example ‘HC’. Paste the certificate string you copied here (already included in this case).

   SQL Copy

– create certificate CREATE CERTIFICATE FROM ‘—–BEGIN CERTIFICATE—–MIIDrzCCApegAwIBAgIQCDvgVpBCRrGhdWrJWZHHSjANBgkqhkiG9w0BAQUFADBhMQswCQYDVQQGEwJVUzEVMBMGA1UEChMMRGlnaUNlcnQgSW5jMRkwFwYDVQQLExB3d3cuZGlnaWNlcnQuY29tMSAwHgYDVQQDExdEaWdpQ2VydCBHbG9iYWwgUm9vdCBDQTAeFw0wNjExMTAwMDAwMDBaFw0zMTExMTAwMDAwMDBaMGExCzAJBgNVBAYTAlVTMRUwEwYDVQQKEwxEaWdpQ2VydCBJbmMxGTAXBgNVBAsTEHd3dy5kaWdpY2VydC5jb20xIDAeBgNVBAMTF0RpZ2lDZXJ0IEdsb2JhbCBSb290IENBMIIBIjANBgkqhkiG 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 DQYJKoZIhvcNAQEFBQADggEBAMucN6pIExIK+t1EnE9SsPTfrgT1eXkIoyQY/EsrhMAtudXH/vTBH1jLuG2cenTnmCmrEbXjcKChzUyImZOMkXDiqw8cvpOp/2PV5Adg06O/nVsJ8dWO41P0jmP6P6fbtGbfYmbW0W5BjfIttep3Sp+dWOIrWcBAI+0tKIJFPnlUkiaY4IBIqDfv8NZ5YBberOgOzW6sRBc4L0na4UU+Krk2U886UAb3LujEV0lsYSEY1QSteDwsOoBrp+uvFRTp2InBuThs4pFsiv9kuXclVzDAGySj4dzp30d8tbQkCAUw7C29C79Fv1C5qfPrmAESrciIxpg0X40KPMbp1ZWVbd4=—–END CERTIFICATE—–’ COMMENT ‘HC’;

> **Why the comment ´HC´?**
>
> In the next step, we will need to obtain the ID of this certificate to add it to our PSE. Using a comment when creating this certificate will make it easier for us to find it and get its ID.




### Add the certificate to the PSE


1.	Get the certificate ID of this certificate by running this SQL statement:

    ```SQL
SELECT CERTIFICATE_ID FROM CERTIFICATES WHERE COMMENT = 'HC';

2. Add this certificate to the certificate store by inserting the certificate ID into the SQL statement:

   SQL Copy

ALTER PSE SSL ADD CERTIFICATE <certificate_id>;

3.	Now set the PSE purpose as remote source. This way, all remote sources you create will use the certificates stored in the PSE. Please note, that only one PSE can be set as remote source purpose.

    ```SQL
SET PSE SSL PURPOSE REMOTE SOURCE;

To now create a remote source, copy and paste the following statement into your console and replace the <placeholders> with your specific information (see instructions below the code).

CREATE REMOTE SOURCE <remote_source_name> ADAPTER hanaodbc
CONFIGURATION 'Driver=libodbcHDB.so;ServerNode=<endpoint>;
encrypt=TRUE;'
WITH CREDENTIAL TYPE 'PASSWORD' USING 'user=<user_name>;password=<password>';

• Enter a name for your remote source to replace <remote_source_name>, e.g. “HC”.
• Paste the endpoint information you copied in step 1 as <endpoint>.
• Include the credentials of the user that has permission to access the SAP HANA Cloud, SAP HANA database instance. You could use the DBADMIN user for the purpose of testing, but for ‘real-world’ use cases this is not recommended. Read more on user creation in SAP HANA Cloud, SAP HANA database here.

Once all this information is included, run the statement. Then refresh and you will now see on the left in your catalog that the remote source has been successfully created.

CAUTION:

If you are using an SAP HANA on-premise version lower than rev45, the steps describing the PSE do not apply for you. Instead, you need to include the certificate string directly in the CREATE REMOTE SOURCE statement following the endpoint information:

CREATE REMOTE SOURCE [remote_source_name] ADAPTER hanaodbc
CONFIGURATION 'Driver=libodbcHDB.so;ServerNode=<endpoint>;
sslTrustStore="-----BEGIN CERTIFICATE-----<certificate_string_as_a_single_line>-----END CERTIFICATE-----";encrypt=TRUE;'
WITH CREDENTIAL TYPE 'PASSWORD' USING 'user=<user_name>;password=<password>';

You can read more about how to create remote sources in the technical documentation here.

Now that the SDA connection between the SAP HANA on-premise database and the SAP HANA Cloud, SAP HANA database has been created, you can virtualise the data from the cloud to on-premise following these steps:

1. You can check whether the remote connection is correctly configured by opening the SAP HANA Database Explorer and clicking on Remote sources. Then click on the newly created remote source (“HC” in this example). Another tab will open, where you can check whether the objects from your remote source can be retrieved. If you are using SAP HANA Studio for your local instance, expand the catalog items HC, then Null, then SYS to see all the system view tables.

   

2. Next, use the SQL Code below to create the virtual table. Make sure to enter the exact name of your SAP HANA Cloud, SAP HANA database instance (at the top of the tile) that you used in the previous step and to include the name of the remote source that you created in step 4. of the previous section (“HC” in our example):

   SQL Copy

CREATE VIRTUAL TABLE WORKSHOP.VT_TABLES AT “HC”."<instance_name>".“SYS”.“TABLES”;

    > If you have chosen a different name for the remote source in the step 4, you need to change the name in this statement accordingly or go back to that step and change the name. We recommend prefixing the name to ´HC´ to avoid confusion later.

3.	Run the statement.




### Check the content of the new virtual table



1.	To check if your virtual table has been created in your on-premise database, open your schema in the catalog of your SAP HANA on-premise.

2. Then, click on **Tables** and you can see the virtual table you have just created. Note, that if you are using the SAP HANA Database Explorer, you must first select TABLES and then filter by the name of your schema.

    ![HANA Studio Virtual Table](https://raw.githubusercontent.com/sap-tutorials/Tutorials/master/tutorials/hana-cloud-mission-extend-05/ss-05-HANAstudio-virtual-table.png)

2.	To check the content of your virtual table, you can run a `SELECT*FROM` statement.

3.	A table view will open. There you can see that the data is being pulled from the remote source to your local SAP HANA on-premise database.

    ![HANA Studio Virtual Table 2](https://raw.githubusercontent.com/sap-tutorials/Tutorials/master/tutorials/hana-cloud-mission-extend-05/ss-06-HANAstudio-virtual-table2.png)

> **Well done!**
>
> You have completed the second tutorial of this group! Now, you know how to use Smart Data Access, or SDA, to virtualise data from an SAP HANA Cloud, SAP HANA database instance to an SAP HANA on-premise database.  
>
> Learn in the next tutorial how to access data the other way around: Setting up a connection between SAP HANA on-premise and SAP HANA Cloud, SAP HANA database with SDI and the DP Agent.





### Test yourself






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