# Migrations & Modernization > Selected Engineer ApS work demonstrating Migrations & Modernization — the achievements that prove it. - [Improved geographical map application performance by 10x through strategic database transition from MSSQL to PostgreSQL, optimizing processing and data security.](https://data.engineer.company/portfolio/improved-geographical-map-application-performance-by-10x-through-6/) - [Implemented a catalogue‑driven deep‑merge for stored JSON preferences, preventing missing‑key crashes as the schema evolves.](https://data.engineer.company/portfolio/implemented-a-catalogue-driven-deep-merge-for-stored-65/) - [Kept the schema honest across 1,022 migrations with a CI gate that builds the database both ways — a fresh install, and an install plus every migration — and fails when the two disagree.](https://data.engineer.company/portfolio/kept-the-schema-honest-across-1022-migrations-99/) - [Moved every user‑facing string out of Python into a content tree of 874 files across three languages, after finding dead translations nobody could see were dead and a check silently grading a third of the achievements.](https://data.engineer.company/portfolio/moved-every-user-facing-string-into-a-content-tree-152/)