Details (Instructions) Read the following narrative below and create an entity-relationship diagram (ERD). Specify all entities (including any weak entities), attributes (specify identifiers), and relationships between entities. Do not convert any many-to-many relationships to associative entities. LIST ALL ASSUMPTIONS that you make when completing this assignment on a page following the diagram. You should have several assumptions listed that correspond to design decisions youve made. Include every assumption (which could be as simple as why youve made a particular decision about a cardinality, or as complex as why you chose to include a quaternary relationship [hint: dont include a quaternary relationship]. Narrative NorthField Inc. is a manufacturing company with several plants in northeastern United States. These plants are responsible for leading different projects that the company might undertake, depending on a plants function. A certain plant might even be associated with several projects, but the project is always under the control of just one plant. Some plants do not undertake any projects at all. If the plant is closed down, projects undertaken by that plant cannot be canceled. The project assignments from a close plant must be temporarily removed in order to allow the project to be transferred to another plant. Employees work in these plants, and each employee works in only one plant. A plant may employ many employees but must have at least 100 employees in order to exist. A plant with employees cannot be closed down. Every plant is managed by an employee who works in the same plant; but every employee is not a plant manager, nor can an employee manage more than one plant. Company policy dictates that every plant must have a manager. If a plant is closed down, the employee no longer manages the plant but becomes an employee of another plant. Some employees are assigned to work on projects and in some cases might even be assigned to work on several projects simultaneously. For a project to exist, it must have at least one employee assigned to it. A project might need several employees, depending on its size and scope. As long as an employee is assigned to a project, his or her record cannot be removed from the database. However, once a project ends, the employee records are removed from the database and all assignments of employees to that project must be removed. Some employees also supervise other employees, but all employees need not be supervised; employees that are supervised are supervised by just one employee. An employee may be the supervisor of several employees but of no more than 20. The human resources department uses a designated default employee number to replace a supervisor who leaves the company. It is not possible for employee to be his or her own supervisor. Some employees may have several dependents. NorthField Inc. does not allow both husband and wife to be an employee of the company. Also, a dependent can onl.

1. Details (Instructions)
Read the following narrative below and create an entity-relationship diagram (ERD). Specify all
entities (including any weak entities), attributes (specify identifiers), and relationships between
entities. Do not convert any many-to-many relationships to associative entities.
LIST ALL ASSUMPTIONS that you make when completing this assignment on a page
following the diagram. You should have several assumptions listed that correspond to design
decisions youve made. Include every assumption (which could be as simple as why youve made
a particular decision about a cardinality, or as complex as why you chose to include a quaternary
relationship [hint: dont include a quaternary relationship].
Narrative
NorthField Inc. is a manufacturing company with several plants in northeastern United States.
These plants are responsible for leading different projects that the company might undertake,
depending on a plants function. A certain plant might even be associated with several projects,
but the project is always under the control of just one plant. Some
plants do not undertake any projects at all. If the plant is closed down, projects undertaken by
that plant cannot be canceled. The project assignments from a close plant must be temporarily
removed in order to allow the project to be transferred to another plant.
Employees work in these plants, and each employee works in only one plant. A plant may
employ many employees but must have at least 100 employees in order to exist. A plant with
employees cannot be closed down. Every plant is managed by an employee who works in the
same plant; but every employee is not a plant manager, nor can an employee manage more than
one plant. Company policy dictates that every plant must have a manager. If a plant is closed
down, the employee no longer manages the plant but becomes an employee of another plant.
Some employees are assigned to work on projects and in some cases might even be assigned to
work on several projects simultaneously. For a project to exist, it must have at least one
employee assigned to it. A project might need several employees, depending on its size and
scope. As long as an employee is assigned to a project, his or her record cannot be removed from
the database. However, once a project ends, the employee records are removed from the database
and all assignments of employees to that project must be removed.
Some employees also supervise other employees, but all employees need not be supervised;
employees that are supervised are supervised by just one employee. An employee may be the
supervisor of several employees but of no more than 20. The human resources department uses a
designated default employee number to replace a supervisor who leaves the company. It is not

2. possible for employee to be his or her own supervisor.
Some employees may have several dependents. NorthField Inc. does not allow both husband and
wife to be an employee of the company. Also, a dependent can only be a dependent of one
employee at a time.
NorthField Inc. offers healthcare benefits such as medical insurance to its employees and to their
dependents. An employee is not required to sign-up for the healthcare benefits. However, most
employees and some of their dependents receive healthcare coverage from NorthField Inc. The
company keeps record of which employee or dependent has an insurance plan through them.
Every insurance plan must belong to at least one employee or dependent. An employees
dependent can be a spouse and children under 26 years of age to qualify for enrollment in the
insurance plan.
To nurture the hobbies of employees dependents, NorthField Inc. sponsors recreational
opportunities. Dependents need not have a hobby, but some dependents may have several
hobbies. Because some hobbies are not as popular as others, every hobby need not have
participants. If a dependent is no longer in the database, no records of that dependents
participation at hobby should exist in the database. Finally, as long as at least one dependent
participates in a hobby, that hobby should continue to exist.
All plants of NorthField Inc. have a plant name, number, budget, and building. A plant has three
or more buildings. Each plant can be identified by either its name or number. NorthField Inc.
operates in seven plants, and the plant numbers can be anything in the range of 10 through 20.
However, either the plant number or the plant name must always be recorded.
The name of an employee of NorthField Inc. consists of the first name, middle initial, last name,
and a nametag. Employee numbers are used to identify employees in the company. However,
names can also be used as identifiers. Both employee number and employee name must be
recorded. Where two or more employees have the same name and one-position numeric nametag
is used so that up to 10, otherwise duplicate, names can be distinguished from one another.
Sometimes, an employees middle initial may not be available.
Although the address, gender (male or female), and hiring date of each employee must be
recorded, salary information is optional. Salaries of NorthField Inc. range from $35,000 to
$90,000. Also, the salary of an employee cannot exceed the salary of an employees supervisor.
The date on which an employee starts working as a manager of a plant should be gathered. In
addition, the number of employees working in each plant should be gathered; this can be
computed. Information about the dependents related to each employee, such as the dependents
name, relationship to the employee, birth date, and gender, should also be captured. The
dependents name as well as how the dependent is related to the employee is mandatory. A
mother or daughter must be a female, a father or son must be a male, and a spouse can be either

3. male or female. Since a dependent cannot exist independently of an employee, the dependents
name and relationship to the employee, in conjunction with either the employee name or the
employee number, is used to identify the dependents of an employee. The number of dependents
of each employee must also be captured, but this, like the number of employees working in each
plant, can be computed.
Projects have unique names and numbers, and their locations must be specified. Every project
must have a project number but sometimes may not have a project name; Project numbers range
from 1 to 40. NorthField Inc.'s projects arelocated in the cities of Stafford, Bellaire, Sugarland,
Blue Ash, and Mason. The amount of time an employee has been assigned to a particular project
should be recorded for accounting purposes.
A health insurance plan is identified by a unique plan ID. Each plan also has a name, description,
a start date, an end date, member premium amount and employees premium amount . An
employee or a dependent cannot have more than one plan.
Hobbies are identified by a unique hobby name and include a code that indicates whether the
hobby is an indoor or outdoor activity and another code that indicates if the hobby is a group or
individual activity. The time spent by a dependent per week on each hobby and the associated
annual cost are also captured.