$1\mathrm{.}3$ Given that, a course generates many classes, but each class is linked to a course.. A student may register in many classes, and a class may have many enrolled students.

$1\mathrm{.}3\mathrm{.}1$ Design an equivalent network model for the above$-$mentioned specification.

$1\mathrm{.}3\mathrm{.}2$ Convert the above model into an entity relationship equivalent that is represented in Crew's Foot notation. Show all the keys.

$1\mathrm{.}3\mathrm{.}3$ Construct the semantic model for above$-$mentioned specification. Each object should have at least three attributes.