I have deleted my database with:
In regard to your last part of the question, this is not as simple as you want it to be. You have to programmatically limit the amount of rows. Like something with the following pseudocode
if number_of_rows in <table> > limit do not insert OR remove oldest row and insert new else insert row
But why would you ever want to limit the amount of rows in a table?
You can infact remove your database programmatically. You have to use a reference to the context to remove it with deleteDatabase