During peak periods, Temporary Employment Corporation (TEC) places temporary workers in companies. TECs manager gives you the following description of the business:

_ TEC has a file of candidates who are willing to work.

_ If the candidate has worked before, that candidate has a specific job history. (Naturally, no job history exists if the candidate has never worked.) Each time the candidate works, one additional job history record is created.

_ Each candidate has earned several qualifications. Each qualification may be earned by more than one candidate. (For example, it is possible for more than one candidate to have earned a Bachelor of Business Administration degree or a Microsoft Network Certification. And clearly, a candidate may have earned both a BBA and a Microsoft Network Certification.)

_ TEC offers courses to help candidates improve their qualifications.

_ Every course develops one specific qualification; however, TEC does not offer a course for every qualification. Some qualifications have multiple courses that develop that qualification.

_ Some courses cover advanced topics that require specific qualifications as prerequisites. Some courses cover basic topics that do not require any prerequisite qualifications. A course can have several prerequisites. A qualification can be a prerequisite for more than one course.

_ Courses are taught during training sessions. A training session is the presentation of a single course. Over time, TEC will offer many training sessions for each course; however, new courses may not have any training sessions scheduled right away.

_ Candidates can pay a fee to attend a training session. A training session can accommodate several candidates, although new training sessions will not have any candidates registered at first.

_ TEC also has a list of companies that request temporaries.

_ Each time a company requests a temporary employee, TEC makes an entry in the Openings folder. That folder contains an opening number, a company name, required qualifications, a starting date, an anticipated ending date, and hourly pay.

_ Each opening requires only one specific or main qualification.

_ When a candidate matches the qualification, the job is assigned, and an entry is made in the Placement Record folder. That folder contains an opening number, a candidate number, the total hours worked, etc. In addition, an entry is made in the job history for the candidate.

_ An opening can be filled by many candidates, and a candidate can fill many openings.

_ TEC uses special codes to describe a candidates qualifications for an opening. The list of codes is shown in table below.

TECs management wants to keep track of the following entities:

COMPANY, OPENING, QUALIFICATION, CANDIDATE, JOB_HISTORY, PLACEMENT, COURSE, and SESSION. Given that information, do the following:

a. Draw the Crows Foot ERDs for this enterprise.

b. Identify all necessary relationships.

c. Identify the connectivity for each relationship.

d. Identify the mandatory/optional dependencies for the relationships.

e. Resolve all M:N relationships.

CODE SEC-45 SEC-60 CLERK PRG-MB PRG-C-+ DBA-ORA DBA-DB2 DBA-SQLSERV SYS-1 SYS-2 NW-NOV WD-CF DESCRIPTION Secretarial work, at least 45 words per minute Secretarial work, at least 60 words per minute General clerking work Programmer, Visual Basic Programmer, C Database Administrator, Oracle Database Administrator, IBM DB2 Database Administrator MS SOL Server Systems Analyst, level 1 Systems Analyst, level 2 Network Administrator, Novell experience Web Developer, ColdFusion