As a software engineer, allow me to explain why Software Engineers assume people know what "Oracle Migration" means, using a very brief simplified history.
In the early days of computers, Oracle was the the Enterprise (top of the line) Database. You were either using Oracle as your database, or you didn't have a database. (Also, computers were expensive, and programmers were cheap labor.)
Over time, computers got cheaper, programmers became more valuable, and competition for Oracle started to appear. Oracle was getting old, massive, and ludicrously expensive. So a sort of mass migration from Oracle to any other database started to happen, as competing databases could offer more business value for cheaper.
Because everyone was trying to migrate away from Oracle before it died completely, it become "common knowledge" that Oracle migration meant migrating away from Oracle. You were either required to use Oracle by contract, or you migrated to something better.
However, to everyone's surprise, the Oracle database survived! And they are still updating! And it isn't completely trash any more. It's still (arguably) ludicrously expensive, but it is at least viable for the foreseeable future (it's currently the #1 Relational Database by stock value, thanks to ludicrously expensive support contracts!). So now that there is no longer a mass exodus from Oracle databases, the "common knowledge" is no longer common, and it is now ambiguous. The old guard will still stand by that Oracle should be ditched in a heartbeat, but the new bloods are used to just working with whatever is handed to them.
Also, context makes all the difference in the world. If you aren't using Oracle, it probably means migrating to; if you are upgrading servers, it means migrating versions, if you do use Oracle, it probably means migrating from.
If it's a blog title, it probably means "from Oracle" because if you are migrating databases, Oracle is still the most common legacy (used since COBOL software days) database in use.