Assignment $1$

Describe and Show an example of each of the following concepts $($The examples should NOT be the ones in textbook or discussed in class$)$

$1$a$.$ Describe the meaning subtype$-$supertype structure, and draw an example.

$1$b$.$ Describe the meaning of a weak relationship, and draw an example.

$1$c$.$ Describe the meaning of minimum cardinalities, and draw an example and state your justification.

$1$d$.$ Describe the meaning of an identifying relationship $($namely ID$-$dependent relationship$),$ draw an example.

$1$e$.$ Describe the meaning of a recursive relationship and draw an example.

Data Modeling Exercises

$2$a$.$ A consulting firm currently has several on$-$going projects. The manager of the firm needs to keep track of the information about each project such as project's ID $($or code$),$ client, project title, description, leader of the project, total number of employees working on this project, and project starting date and ending date, budget, etc. The manager also needs to keep track of the information of all employees in this firm, including employee's ID$,$ name, job title, salary, telephone, etc. The manager needs to know which employee participates in what projects. Assuming each project can have many employees working on it$,$ an employee can work on more than one project. The firm also needs to hire short$-$term contractors in some projects' development. The firm also needs to keep track of these contractors' contact information such as name, email, phone number, etc. Each project has some sponsor$($s$)$ who provide$($s$)$ funding or technical support for the project development. Once a project is successfully completed. It will benefit some of the clients of the consulting firm. The consulting firm needs to keep track the information about projects' sponsors and clients, such as contact name$/$nhone$/$address$.$ It also needs to keen track of the amount of funds and the

Iity: Good to go

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