As statox explained, Vim is a text editor, not a database tool, not a coffee machine. But if you want to augment Vim's potential with external tools, you can, and you should!
On your specific question, you really should learn to use your database CLI. It'll give you the best knowledge of what's inside your DB. And because it will be a CLI, you can call it/read from Vim.
As an example, look at https://github.com/mattn/vdbi-vim/blob/master/autoload/vdbi.vim. It's another DB plugin visualisation.
It's wrapping the SELECT ... in functions so you can use them against different DBS. In a nutshell it's reading from the cli and putting it in the buffer.
It's cool and all, but it's not using Vim to anything related to the DB. You're using Vim to diplay the result of your query, and manipulate it and :g/re/p it if you want.
Vim is a text editor.