1. Make a schema migration that will work both with old and new code
2. Make a code change
3. Clean up schema migration
Example: deleting a field:
1. Schema migration to make the column optional
2. Remove the field in the code
3. Schema migration to remove the column
Yes, it's more complex than creating one schema migration, but that's the price you pay for zero-downtime. If you can relax that to "1s downtime midnight on sunday", you can keep things simpler. And if you do so many schema migrations you need such things often ... I would submit you're holding it wrong :)
1. Make a schema migration that will work both with old and new code
2. Make a code change
3. Clean up schema migration
Example: deleting a field:
1. Schema migration to make the column optional
2. Remove the field in the code
3. Schema migration to remove the column
Yes, it's more complex than creating one schema migration, but that's the price you pay for zero-downtime. If you can relax that to "1s downtime midnight on sunday", you can keep things simpler. And if you do so many schema migrations you need such things often ... I would submit you're holding it wrong :)