Q$1.$ Consider the following set of simplified requirements for a LOL database that is used to keep track of the interactions between heroes, skills and equipments.

$($i$)$ Each hero has a unique hero ID$,$ hero name, gender, and e$-$mail. Each hero must own several skills. A hero may buy several equipments.

$($ii$)$ Each skill has a unique skill ID and a skill name. A skill may be owned by only one hero. A skill may be supported by an equipment.

$($iii$)$ Each equipment has a unique equipment number, subject and content. An equipment may be bought by several heroes. An equipment can be used to support several skills.

$($a$)(8\%)$ Draw an ER $($Entity$-$Relationship$)$ diagram for this application. You need to clearly indicate the cardinality ratio $(1$:$1,1$:N$,$ or M:N$)$ and participation constraints $($total or partial$)$ of each relationship. $($State clearly any additional assumptions you make$)$

$($b$)(5\%)$ Map the ER schema into the corresponding relational database schema diagram. Specify all the primary keys and foreign keys.

$($iv$)$ Suppose that Heroes can be distinguished as god$-$Heroes and black$-$Heroes. The database records the number of "like" for God heroes and the number of "unlike" for black$-$Herores, respectively. Please draw the EER model.

$($c$)(3\%)$ Modify the ER schema in $($a$)$ according to the above requirements, using ER and Enhanced ER concepts of specialization and generalization. You need to clearly indicate the disjointness and completeness constraints. $($State clearly any additional assumptions you make$)$