$4.(5$ points$)$ Why aren$$t many$-$to$-$many relationships implemented in a relational database management system? Do some research and explain using an example with tables and attributes and provide at least one external reference in proper APA format.

$5.(2$ points$)$ Create a database named mystore on the local MySQL server.

$6.(2$ points$)$ Remove the UPDATE privilege on the table toys from the MySQL user mila.

$7.(2$ points$)$ Use SQL code to insert the values NULL, P$001,$ and $$6\mathrm{.}99$ into the PARTS table.