Migrate Your Mendix Database

Introduction

This document explains how to migrate the data in an existing Mendix database to another Mendix database. This can be useful if you want to migrate from one type of database to another, for example MS SQL Server to PostgreSQL.

After completing this how-to you will know how to do the following:

• Migrate a non-PostgreSQL database to a PostgreSQL database
• Export a PostgreSQL database
• Upload an exported PostgreSQL database to Mendix Cloud
• Export a Mendix Cloud database
• Import into an on-premise PostgreSQL database
• Migrate a PostgreSQL database to a non-PostgreSQL database, including migrating a PostgreSQL database to SAP HANA

Overview

You can copy all the data from any Mendix-supported database management system to any other Mendix-supported database management system. For example you can copy demo, test, and production databases from built-in to PostgreSQL, and from PostgreSQL to built-in. You can also migrate production data from SQL Server or Oracle (on-premises) to PostgreSQL in our cloud.

To do this, start your app on the database you would like to copy the data to. This database should already exist and should be totally empty. To let Mendix know from which database all data should be copied, you have to set some custom configuration settings. These custom settings identify the source database and give Mendix the authentication required to access it.

The most commonly used custom settings for database migration are:

• SourceDatabaseType (HSQLDB, MYSQL, ORACLE, POSTGRESQL, SQLSERVER)
• SourceDatabaseHost
• SourceDatabaseName
• SourceDatabaseUserName
• SourceDatabasePassword

For more information on the full list of available settings, see Runtime Customization.

These settings can be configured as follows:

• Studio Pro – in Project Explorer, expand Project, double-click Settings, edit a configuration, and go to the Custom tab:

  

• Service Console – click an app in the left pane, click Configuration, click Advanced, then see Custom Mendix settings:

  

• m2ee-tools – add the custom settings to the mxruntime section (for more information, see Full Documented m2ee)

You can migrate databases using Studio Pro, the Service Console, or m2ee-tools. The Service Console gives you the advantage of seeing a progress bar during the copy process, which is handy if you copy a lot of data which takes a long time to execute.

Using your PostgreSQL Database in Studio Pro

You can configure Studio Pro to use a PostgreSQL database instead of the inbuilt (HSQLDB) database.

To do this, perform the following steps:

1. Open your Project ‘…’ > Settings.

2. Click New to add a new configuration from the Configurations tab.

3. Give your configuration a new Name.

4. On the Database tab, set the following values:

   • Type – PostgreSQL
   • Database name – default
   • URL – the URL for your local PostgreSQL server
   • User name – the user name of a database administrator in your local PostgreSQL
   • Password – the password for the user specified above

   

   Your new configuration will be set as the active configuration.

5. Ensure that PostgreSQL is running locally on the correct port.

6. Run your app locally. Provided your PostgreSQL database is empty, your app will configure the database to support the domain model of your app.

Migrating a Non-PostgreSQL Database to a PostgreSQL Database

Mendix Cloud environment only uses PostgreSQL as a database server. The recommended way is to migrate your existing on-premises non-PostgreSQL source database to a new on-premises PostgreSQL target database.

The source database is the database with the data that you would like to migrate to the cloud. The target PostgreSQL database should be completely empty, as in, it should not contain any tables. In the Mendix project the active configuration in Settings should point to the target database, and you should add the Custom configuration settings for the source database as explained above in the overview.

Having configured the Mendix project, just run the application locally and it will automatically migrate the database schema and all the data from the source database to the target database. Before exporting the target database, you should always validate it first by viewing the application in a browser.

Exporting a PostgreSQL Database

To export a PostgreSQL database, refer to either the pg_dump command line tool or the PG Admin visual tool documentation to understand how to create a backup of your new PostgreSQL database.

Uploading an Exported PostgreSQL Database to Mendix Cloud Database

Use Mendix Portal to upload the migrated, exported database backup to Mendix Cloud. This can be accessed using the Nodes page in Apps: select your app and environment, click Details, click the Backup tab and use the Upload Data button to upload your Database using the file chooser to select the exported database file from your local file system. This will stop and clear your existing environment.

Exporting a Mendix Cloud Database

The same procedure can be used to export an existing Mendix Cloud database, import it into an on-premises PostgreSQL source database and migrate that to an on-premises non-PostgreSQL target database.

Export the Mendix Cloud database via the Mendix Portal. This can be accessed using the Nodes page in the Mendix Portal:

1. Select your app and environment.
2. Click Backups.
3. Optionally, create a fresh backup with recent data by clicking Create Backup.
4. On the backup you want to download, click More Options > Download. This downloads the database to your local file system using the database URL shown in the dialog box.

Importing into an On-premises PostgreSQL Database

To import a PostgreSQL database using the downloaded database file, refer to either the pg_dump command line tool or the pgAdmin visual tool documentation to understand how to restore your downloaded database file.

Migrating a PostgreSQL Database To a Non-PostgreSQL Database

Below is general guidance on how to migrate a PostgreSQL database to a different database. There is a special section for the case of migrating a PostgreSQL database being used by a Mendix application running on SAP Business Technology Platform (SAP BTP).

General Guidance

The source database is a PostgreSQL database with the downloaded database from Mendix Cloud. The target non-PostgreSQL database should be completely empty, as in, it should not contain any tables. In the Mendix project the active configuration in Settings should point to the target database, and you should add the Custom configuration settings for the source PostgreSQL database as explained above in the overview.

Having configured the Mendix project, just run the application locally and it will automatically migrate the database schema and all the data from the source database to the target database. You should always validate it first by viewing the application in a browser.

Migrating to SAP HANA on SAP BTP

If you have a Mendix application running on SAP BTP with PostgreSQL as the database service and want to migrate the database to SAP HANA, you will need to take some extra steps to migrate the existing data.

To do this, perform the following steps:

1. Sign in to the SAP BTP, Cloud Foundry environment (containing the PostgreSQL service) using the Cloud Foundry command line.

2. Get the PostgreSQL service instance details from the environment variables of the application using the following command:

   cf env {application-name}

3. Inspect the VCAP_SERVICES list, and note down the values of the following properties in the postgresql service:

   • dbname – {dbname}
   • hostname – {hostname}
   • password – {password}
   • port – {port}
   • username – {username}

   as shown in the highlighted image below:

   

4. Create an environment using the SAP HANA database service using Mendix Portal.

5. Deploy the mda, but do not start the application.

6. Sign in to the SAP BTP, Cloud Foundry environment (containing the SAP HANA service) using the Cloud Foundry command line.

7. Set the following runtime properties in the SAP HANA environment using the command line. Use the values from the PostgreSQL instance values you noted above.

   cf set-env {application-name} MXRUNTIME_SourceDatabaseType POSTGRESQL
   cf set-env {application-name}  MXRUNTIME_SourceDatabaseHost {hostname}:{port}
   cf set-env {application-name} MXRUNTIME_SourceDatabaseName {dbname}
   cf set-env {application-name}  MXRUNTIME_SourceDatabaseUserName {username}
   cf set-env {application-name}  MXRUNTIME_SourceDatabasePassword {password}
   

8. Start the application either from the Mendix Portal or the command line.

9. Once the application is started, verify the data in the application.