I made this mini database managment system as a project for a class at Eastern. The Github page has a detail of the commands in depth.
My Mini DBMS uses very SQL-like commands - the specification of my professor. And, while it doesn't have near the level of query optimization a commerical database might implement, it does work to separate a query's conditions to reduce redudant checks through selection cascading and condition splitting. Selection cascading is the process of reducing the number of comparisions done on any tuple by removing a tuple as early as possible from the condition checking process - e.g. given x and y, if x is false, then y is irrelevant. And, condition splitting is the process of splitting up the given condition when possible logically so that, when selecting from multiple tables, each table can be filtered before creating a cartesian product. This allows for index searches and other shortcuts to reduce work. Unfortunately, the static server this page is hosted on does not allow me to create a working demo. I can really only point to where the code is hosted.
Check out the Github page!Date Created.