Lets take this: Company using Microsoft Server Database since 2008. Its company what heavily depends on working with data from databases. (Construction company ) Current database is outdated and not very structured because people what was working on it in 2008 developed it fast and not very intelligently.
I decided to suggest them rebuild of current database structure to make everything clearer, faster and more reliable.
My main question is if there are any main differences between MySQL (MariaDB), PostgreSQL, Oracle, Microsoft database systems. I know that using "paid" databases is "always better" but I dont see any differences in performance or reliability of these relational databases. Are there any? If yes, why they are better for usage in enterprise project instead of others (Do not answer to last question if u thing its option based)?