2. Create a complete ERD in Crow’s Foot notation that can be implemented in the relational model using the following description of operations. Hot Water (HW) is a small start-up company that sells spas. HW does not carry any stock. A few spas are set up in a simple warehouse so customers can see some of the models available, but any products sold must be ordered at the time of the sale.
· HW can get spas from several different manufacturers.
· Each manufacturer produces one or more different brands of spas.
· Each and every brand is produced by only one manufacturer.
· Every brand has one or more models.
· Every model is produced as part of a brand. For example, Iguana Bay Spas is a manufacturer that produces Big Blue Iguana spas, a premium-level brand, and Lazy Lizard spas, an entry-level brand. The Big Blue Iguana brand offers several models, including the BBI-6, an 81-jet spa with two 6-hp motors, and the BBI-10, a 102-jet spa with three 6-hp motors.
· Every manufacturer is identified by a manufacturer code. The company name, address, area code, phone number, and account number are kept in the system for every manufacturer.
· For each brand, the brand name and brand level (premium, mid-level, or entry-level) are kept in the system.
· For each model, the model number, number of jets, number of motors, number of horsepower per motor, suggested retail price, HW retail price, dry weight, water capacity, and seating capacity must be kept in the system.
4. Create an ERD based on the Crow’s Foot notation, using the following requirements:
· An INVOICE is written by a SALESREP. Each sales representative can write many invoices, but each invoice is written by a single sales representative.
· The INVOICE is written for a single CUSTOMER. However, each customer can have many invoices.
· An INVOICE can include many detail lines (LINE), each of which describes one product bought by the customer.
· The product information is stored in a PRODUCT entity.
· The product’s vendor information is found in a VENDOR entity.
3. Using the INVOICE table structure shown in Table P6.3, do the following:
8. Use the dependency diagram shown in Figure P6.8 to work the following problems.
1. Break up the dependency diagram shown in Figure P6.8 to create two new dependency diagrams: one in 3NF and one in 2NF.
2. Modify the dependency diagrams you created in Problem 8a to produce a set of dependency diagrams that are in 3NF. (Hint: One of your dependency diagrams will be in 3NF but not in BCNF.)
3. Modify the dependency diagrams you created in Problem 8b to produce a collection of dependency diagrams that are in 3NF and BCNF.