Chapter $5$ Homework Figure $5\mathrm{.}4$ Specialization Hierarchy with Overlapping Subtypes

Draw an extended entity$-$relationship diagram $($EERD$)$ based on the scenario below. If you discover while

drawing the diagram that the scenario is incomplete, make up reasonable explanations to complete the story

and supply your explanations along with the diagram.

Scenario

ABC company wants to develop a database to keep information on its computers. The company has only

two types of computers$-$ laptop and tablet. The company tag number and computer model number are kept

for each computer. The unique attribute for laptop is keyboard; for tablet is touch$\_$screen

Note: In addition to the attributes given in the scenario, add at least two $(2)$ more attributes of your choice

for computer entities.

Requirements:

Your EERD looks like the one shown in Figure $5\mathrm{.}4.$ Your EERD must show

Entity: The proper number of entities and their names

Attributes: In addition to the attributes given in the scenario, add at least two $(2)$ more

attributes of your choice for employee and computer entities.

Primary key and Foreign key

Relationship:

Max. and Min. cardinalities: If needed, you can put your justifications on

your answer document about why you use the cardinality

Description $($text$)$ of the relationship between entities $($e$.$g$.,$ takes, advises,

has, etc.$)$

Disjoint$/$overlapping constraints

Subtype discriminators

Partial$/$total completeness

Use Crow's foot model $($notation$)$

Included figure $5\mathrm{.}4$ as an example I really need help.