Create an ER model for this business situation. Your model should include only entities and relationships, no attributes. You may use either Crow's Foot notation or UML notation. Whichever notation you use, be sure to label your relationships in both directions.

Note that you must include intersection entities that implement M:N relationships in your model.

A Data Dictionary showing the attributes for the entities of the ER model

Create a data dictionary for your ER model. All attributes including keys and foreign keys must be identified. Use these naming conventions for tables and attributes in your data dictionary. Entity names should match problem the domain and be understandable to users of the system. Attributes uses as keys or foreign keys being with c_, other attributes begin with letters that indicate their data type including, t_ for text d_ for date, n_ for numbers with decimal places, i_ for integers, b_ for boolean, etc. Attributes should also have a two charcter suffix derived from the table name, e.g., _cu for a customer table. The primary key of the customer table would be something like c_customer_cu, the date of first order by the customer might by d_firstOrder_cu, and the current balance would be n_currentBalance_cu.

Global Computer Solutions (GCS) is an information technology consulting company with many offices throughout the United States. The companys success is based on its ability to maximize its resourcesthat is, its ability to match highly skilled employees with projects according to region. To better manage its projects, GCS has contacted you to design a database so GCS managers can keep track of their customers, employees, projects, project schedules, assignments, and invoices.

The GCS database must support all of GCSs operations and information requirements. A basic description of the main entities follows:

• The employees of GCS must have an employee ID, a last name, a middle initial, a first name, a region, and a date of hire recorded in the system.

• Valid regions are as follows: Northwest (NW), Southwest (SW), Midwest North (MN), Midwest South (MS), Northeast (NE), and Southeast (SE).

• Each employee has many skills, and many employees have the same skill.

• Each skill has a skill ID, description, and rate of pay. Valid skills are as follows: Data Entry I, Data Entry II, Systems Analyst I, Systems Analyst II, Database Designer I, Database Designer II, Cobol I, Cobol II, C++ I, C++ II, VB I, VB II, ColdFusion I, ColdFusion II, ASP I, ASP II, Oracle DBA, MS SQL Server DBA, Network Engineer I, Network Engineer II, Web Administrator, Technical Writer, and Project Manager. Table P5.11a shows an example of the Skills Inventory.

• GCS has many customers. Each customer has a customer ID, name, phone number, and region.

• GCS works by projects. A project is based on a contract between the customer and GCS to design, develop, and implement a computerized solution. Each project has specific characteristics such as the project ID, the customer to which the project belongs, a brief description, a project date (the date the contract was signed), an estimated project start date and end date, an estimated project budget, an actual start date, an actual end date, an actual cost, and one employee assigned as the manager of the project.

• The actual cost of the project is updated each Friday by adding that weeks cost to the actual cost. The weeks cost is computed by multiplying the hours each employee worked by the rate of pay for that skill.

• The employee who is the manager of the project must complete a project schedule, which effectively is a design and development plan. In the project schedule (or plan), the manager must determine the tasks that will be performed to take the project from beginning to end. Each task has a task ID, a brief task description, starting and ending dates, the types of skills needed, and the number of employees (with the required skills) needed to complete the task. General tasks are the initial interview, database and system design, implementation, coding, testing, and final evaluation and sign-off.

• GCS pools all of its employees by region; from this pool, employees are assigned to a specific task scheduled by the project manager. For example, in the first projects schedule, you know that a Systems Analyst II, Database Designer I, and Project Manager are needed for the period from 3/1/16 to 3/6/16. The project manager is assigned when the project is created and remains for the duration of the project. Using that information, GCS searches the employees who are located in the same region as the customer, matches the skills required, and assigns the employees to the project task.

• Each project schedule task can have many employees assigned to it, and a given employee can work on multiple project tasks. However, an employee can work on only one project task at a time. For example, if an employee is already assigned to work on a project task from 2/20/16 to 3/3/16, the employee cannot work on another task until the current assignment is closed (ends). The date that an assignment is closed does not necessarily match the ending date of the project schedule task because a task can be completed ahead of or behind schedule.

• Given all of the preceding information, you can see that the assignment associates an employee with a project task, using the project schedule. Therefore, to keep track of the assignment, you require at least the following information: assignment ID, employee, project schedule task, assignment start date, and assignment end date. The end date could be any date, as some projects run ahead of or behind schedule.

• Employee work hours are kept in a work log, which contains a record of the actual hours worked by employees on a given assignment. The work log is a form that the employee fills out at the end of each week (Friday) or at the end of each month. The form contains the date, which is either the current Friday of the month or the last workday of the month if it does not fall on a Friday. The form also contains the assignment ID, the total hours worked either that week or up to the end of the month, and the bill number to which the work-log entry is charged. Obviously, each work-log entry can be related to only one bill.

• Finally, every 15 days, a bill is written and sent to the customer for the total hours worked on the project during that period. When GCS generates a bill, it uses the bill number to update the work-log entries that are part of the bill. In summary, a bill can refer to many work-log entries, and each work-log entry can be related to only one bill. GCS sent one bill on 3/15/16 for the first project (SEE ROCKS), totaling the hours worked between 3/1/16 and 3/15/16. Therefore, you can safely assume that there is only one bill in this table and that the bill covers the work-log entries shown in the preceding form.