This is a test to see how Flyway works with an existing DB.

If we already have a DB with a table, and then add Flyway to the project, how will it behave? How can we bring the DB up to date with the current migration.

Will need to use baseline to initialize the migration history table.

Baseline version should be the current migration script that the DB is at.

Flyway can create the schemas automatically, but it needs to be told which schemas in configuration.

Schema can then either be hard-coded as part of the application's config, or hidden in .env / environment variables.

It can create and manage multiple schemas, but it can only migrate one at a time.

It doesn't make sense for the production config to also create a test database, so we'd probably have just the one schema in each config, and then have a separate config for the test database.

Trouble is that flyway.url defaults to datasource.url which includes the schema that doesn't exist yet, so connection fails. We then have to override flyway.url to remove the schema. When we do that, Flyway then also changes the credentials, so we have to provide them also.

For a total of:

spring.datasource.url=${DB_URL}/flyway_existing_db_demo
spring.datasource.username=${DB_USERNAME}
spring.datasource.password=${DB_PASSWORD}
spring.flyway.url=${DB_URL}
spring.flyway.user=${DB_USERNAME}
spring.flyway.password=${DB_PASSWORD}
spring.flyway.schemas=flyway_existing_db_demo

It would be nice if datasource.url could be used as the default for flyway.url, but with the schema removed, or if datasource.url didn't need schema, and it could be provided separately. This doesn't seem possible. spring.jpa.properties.hibernate.default_schema didn't work.