Using the Relationship-Entity-Attribute modeling technique, create an entity relationship diagram that details this business scenario OR what would an entity-relationship (ER) diagram look like if the standard diagram included cardinalities?
Green, Inc has asked you to create a database to keep track of all details of the services (lawn care) performed as well as the payments. Green, Inc has requested that the database not be designed to track purchases or company disbursements. During the course of business, Green gets requests through the website and when Tom, Abu, or Jean are contacted. When the request is received a work order then begins. The work order lists the services the client is requesting (which can be one or many).
All field workers (#1-#5) perform the services and are able to do so. A particular service may be done for many work orders and a work order may require many serivces.
Green, Inc. also wants the database to keep track of the time employees spend on any type of service or task (such as weeding, mowing, etc). Thus, customer charges for services are based on a standard method of service multiplied by time. Hourly rates are fixed, and it may take many employees to do any one service or task.
Customers are charged based on estimates from sales representatives, these estimates are calculated from hourly rates and standard or average times for completion. Customers are only billed for actual time employees consume on any services provided.
Green, Inc. allows customers to pay in installments if they want to. Most customers pay in installments at regular periodic intervals for the many work orders they have recently had. Partial payments on any one or many work orders are allowed.