I am a big fan of a relational model. SQL itself is OK but far from great. So, I wish you a lot of success!

I was part of a similar attempt - building a better "SQL" and relational DB. This was roughly 8 years a go. You can have a look at our GitHub Projects or look at some further links and may be you get inspired :)

* http://bandilab.github.io/ - introduction to the bandicoot project

* https://www.infoq.com/presentations/Bandicoot/ - presentation of the Bandicoot language on

* https://github.com/ostap/comp - another interesting attempt, a query language based on a list comprehension