Pre- and Post-migration scripts for Flyway

问题:

I am looking for a way to execute a hook script before and after migration. I have a bunch of views and stored procedures and would like the process to be:

1. Drop all views and stored procedures.
2. Run the migration.
3. Rebuild views and stored procedures.

This insures that any change to the schema is reflected in related views and stored procedures. Steps (1) and (3) will be bash scripts.

Is this possible in Flyway?

回答1:

Update 2014-04-29: This is now Possible with Flyway 3.0 by implementing the FlywayCallback interface.

Previous answer

The short answer is: no, not at this point.

Here is the reason: I thought about this as well as I was laying down the initial design for Flyway. The more I thought about this aspect though, the more it became clear to me that these pre and post scripts are also an integral part of the migration, or at least something a migration can not do without if it wants to be successful. Therefore I would recommend to either:

• Merge 1, 2 & 3 in a single migration
• Have 3 separate migrations x.1 (drop views), x.2 (actual migration), x.3 (rebuild views)

You might even be able to have x.1 and x.3 call stored procedures that do the work for you to avoid code duplication between migrations if these steps are repeating.

Having Flyway take care of performing all changes to the database structure makes the whole thing more straightforward, avoiding a mix of different technologies.

回答2:

To expand on Axel's response: callbacks with sql scripts simply means putting beforeMigrate.sql (for instance, this is one keyword among others) in the directory containing the migrations, and Flyway will execute beforeMigrate.sql before the other migration scripts. Even before schema_version gets locked.

Other callback names (e.g. afterMigrate) are listed in the documentation for callbacks.