add hint about flyway usage (#4086)

* add hint about flyway usage

* added a second comment about removing the property after init

* style(formatting): technical review

* moved to troubleshooting

* removed accidently copied section

* style(formatting): uppercase Flyway

---------

Co-authored-by: Christina Ausley <[email protected]>

docs/self-managed/modeler/web-modeler/troubleshooting/troubleshoot-database-connection.md

@@ -6,6 +6,16 @@ sidebar_label: "Database connection"
 
 You try to start Web Modeler, and encounter issues with the database connection.
 
+## Using a non-empty schema
+
+As Web Modeler uses [Flyway](https://www.red-gate.com/products/flyway/community/) to manage schema updates, the schema should not be shared.
+
+Before the first initialization, ensure no tables or functions are present in your schema.
+
+If your database setup requires mandatory tables or functions, Flyway may throw an exception like `Found non-empty schema(s) "<schema name>" without schema history table!`
+
+To overcome this issue, add the property `spring.flyway.baselineOnMigrate: true` to your Web Modeler configuration and remove it after the schema has been initialized.
+
 ## Secure connection to standard PostgreSQL
 
 Refer to the [database configuration guide](../configuration/database.md#configuring-ssl-for-the-database-connection)

versioned_docs/version-8.2/self-managed/modeler/web-modeler/troubleshooting/troubleshoot-database-connection.md

@@ -10,6 +10,16 @@ Web Modeler Self-Managed is available to [enterprise customers](../../../../refe
 
 You try to start Web Modeler, and encounter issues with the database connection.
 
+## Using a non-empty schema
+
+As Web Modeler uses [Flyway](https://www.red-gate.com/products/flyway/community/) to manage schema updates, the schema should not be shared.
+
+Before the first initialization, ensure no tables or functions are present in your schema.
+
+If your database setup requires mandatory tables or functions, Flyway may throw an exception like `Found non-empty schema(s) "<schema name>" without schema history table!`
+
+To overcome this issue, add the property `spring.flyway.baselineOnMigrate: true` to your Web Modeler configuration and remove it after the schema has been initialized.
+
 ## Secure connection to standard PostgreSQL
 
 Refer to the [database configuration guide](../configuration/database.md#configuring-ssl-for-the-database-connection)

versioned_docs/version-8.3/self-managed/modeler/web-modeler/troubleshooting/troubleshoot-database-connection.md

@@ -10,6 +10,16 @@ Web Modeler Self-Managed is available to [enterprise customers](../../../../refe
 
 You try to start Web Modeler, and encounter issues with the database connection.
 
+## Using a non-empty schema
+
+As Web Modeler uses [Flyway](https://www.red-gate.com/products/flyway/community/) to manage schema updates, the schema should not be shared.
+
+Before the first initialization, ensure no tables or functions are present in your schema.
+
+If your database setup requires mandatory tables or functions, Flyway may throw an exception like `Found non-empty schema(s) "<schema name>" without schema history table!`
+
+To overcome this issue, add the property `spring.flyway.baselineOnMigrate: true` to your Web Modeler configuration and remove it after the schema has been initialized.
+
 ## Secure connection to standard PostgreSQL
 
 Refer to the [database configuration guide](../configuration/database.md#configuring-ssl-for-the-database-connection)

versioned_docs/version-8.4/self-managed/modeler/web-modeler/troubleshooting/troubleshoot-database-connection.md

@@ -10,6 +10,16 @@ Web Modeler Self-Managed is available to [enterprise customers](../../../../refe
 
 You try to start Web Modeler, and encounter issues with the database connection.
 
+## Using a non-empty schema
+
+As Web Modeler uses [Flyway](https://www.red-gate.com/products/flyway/community/) to manage schema updates, the schema should not be shared.
+
+Before the first initialization, ensure no tables or functions are present in your schema.
+
+If your database setup requires mandatory tables or functions, Flyway may throw an exception like `Found non-empty schema(s) "<schema name>" without schema history table!`
+
+To overcome this issue, add the property `spring.flyway.baselineOnMigrate: true` to your Web Modeler configuration and remove it after the schema has been initialized.
+
 ## Secure connection to standard PostgreSQL
 
 Refer to the [database configuration guide](../configuration/database.md#configuring-ssl-for-the-database-connection)

versioned_docs/version-8.5/self-managed/modeler/web-modeler/troubleshooting/troubleshoot-database-connection.md

@@ -10,6 +10,16 @@ Web Modeler Self-Managed is available to [enterprise customers](/reference/licen
 
 You try to start Web Modeler, and encounter issues with the database connection.
 
+## Using a non-empty schema
+
+As Web Modeler uses [Flyway](https://www.red-gate.com/products/flyway/community/) to manage schema updates, the schema should not be shared.
+
+Before the first initialization, ensure no tables or functions are present in your schema.
+
+If your database setup requires mandatory tables or functions, Flyway may throw an exception like `Found non-empty schema(s) "<schema name>" without schema history table!`
+
+To overcome this issue, add the property `spring.flyway.baselineOnMigrate: true` to your Web Modeler configuration and remove it after the schema has been initialized.
+
 ## Secure connection to standard PostgreSQL
 
 Refer to the [database configuration guide](../configuration/database.md#configuring-ssl-for-the-database-connection)