How to properly roll out database migrations without failures? How to delete fields?

To run database migrations without failures, you need to follow several rules:

• Use a migration tool (Flyway, Liquibase, Flyway, or built-in ORM tools).
• Write migrations to be idempotent and reversible, if possible.
• Break migrations into small atomic steps.
• Test migrations on copies of the production database.
• Perform migrations within transactions, if the DBMS supports it.
• Plan migrations considering load and downtime.

How to delete fields:

• First, stop using the field in the code (remove references).
• Perform a migration that marks the field as deprecated (for example, stop writing to it).
• After some time, when you are sure the field is not used, perform a migration to delete the column.

This helps avoid failures due to missing data or code errors that still reference the field.