From an engineering perspective you should not think you can solve whatever issue you have by writing your own database. Writing one is one of the harder tasks

From an engineering perspective you should not think you can solve whatever issue you have by writing your own database. Writing one is one of the harder tasks in computer science. You should write a database system if you want to, for learning, fun, to try out a lot of different approaches, and see how and why things are solved in other DBMS systems. You can even try using it on small fun projects. Dont ever think of putting into production on something important. It will come back and haunt you in the most undesirable ways.