1.264 Midterm Exam Solutions Fall, Name:

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1 1.264 Midterm Exam Solutions Fall, 2006 Name: Exam guidelines: minutes are allowed to complete the exam. 2. Open notes, open book. 3. No laptop computers or calculators are allowed. 4. No cell phones or messaging devices are allowed. Please turn off any that you have brought.

2 1. Software process (32 points) You have been hired as a supply chain/manufacturing consultant to create a good manufacturing schedule and to implement a factory management module for a very light jet (VLJ) aircraft manufacturing firm. This software module will put your analysis results in an operational framework to allow the VLJ company to run its plant; your analytical expertise is needed to model the situation and to decide what to optimize, and how. You have chosen the Production Scheduler module from i2, which can: Create manufacturing schedules for your plant Model the constraints (capacity, process and materials) of your plant Send scheduling data to your manufacturing subsystems in the plant (but not receive any data from them) (i2 is a standard vendor of production scheduling software, used by many companies.) The module heuristically minimizes manufacturing (setup, production, labor, and inventory) costs. It thus requires cost inputs from the finance department such as inventory carrying costs, labor budgets and shipping costs. It is driven by a demand forecast generated from the marketing department and executive management, which is used to create a master production schedule for finished assemblies, and component production plans for all the sub assemblies. VLJ technology is very new; designs for many detailed elements are still evolving; costs are quite variable; and demand is highly uncertain. The executive management of the VLJ company have told you that the plant will be running in 6 months. Period. And that the production scheduling system must be operational for the plant to open. a. What lifecycle model would you choose for the analysis and software implementation of the manufacturing schedule? List at least 5 reasons. (8 points) Spiral model, with two 3 month spirals. First spiral needed to: Determine requirements: understand inputs (from other systems and groups, not Web pages), understand outputs (what manufacturing subsystems need), understand data model (is needed data available, in what form) Do analysis: model and perform optimization analyses, evaluate what works Do first configuration of i2 scheduling module: allow learning curve, determine data model, business rules, find mismatches between i2 module and your rules Manage risk: Bring system to usable state in three months, even if primitive, to lessen risk of having nothing in 6 months Establish and test initial interfaces with master schedule; initial integration, even if limited and simple Second spiral needed to:

3 Refine requirements based on first spiral Refine modeling and analysis based on first spiral Configure i2 scheduling module for initial release based on first spiral Implement better integration, even if some manual work still required or limitations still present Bring system to more usable state at 6 month point by eliminating as many problems as possible from first spiral version b. List at least three lifecycle models you would not choose, and the reasons why. (8 points) 1. Waterfall, which would give no time to adjust analysis or software based on actual experience. 2. Modified waterfall, which would give too limited feedback from implementation to requirements, or QA to design. Risks are very high, and modified waterfall does not manage them as effectively as spiral model and its variations. 3. Code and fix, the most likely to be chosen in real life, would give little control, visibility or ability to manage risks, refine requirements or design. 4. Evolutionary prototyping is not a good choice. Prototypes often focus on user interface, which is not the major issue here. Refine until acceptable is not the paradigm here; there is a hard deadline. 5. Staged delivery is possible but probably not the best choice. There is only one stage, at the 6 month point, that matters. While there will almost certainly be future stages, they don t matter at this point. 6. Design to schedule is a viable model that could be used, but probably not the best choice. In this setting, it s unlikely you ll have items at high, medium and low priority. The challenge is to get the high priority items, all needed for the plant to work, done by month Evolutionary delivery: not suited for hard deadlines. c. Describe how you would prepare a requirements document and estimate the resources required to do the analysis and configure the i2 Production Scheduler module. (8 points) 1. Write narrative 2. Count function points/methods by estimating inputs (from other systems, not Web pages, so use external files ), outputs (to other systems, so use external files ), and database tables (understand and modify the design of the i2 software tables early) 3. Choose the development environment (database, programming language), though it s mostly determined by i2

4 4. Determine the lines of code to be generated to configure and implement the system 5. Determine type of software (systems) and type of team (probably fastest possible schedule) 6. Find estimates from tables and convergence graph, but make sure your upper limit is 6 months. 7. Determine team size; use similar methods to steps 1 6 to determine analysis effort on project d. List the four most important risks, and how you would manage them. (8 points) 1. People. Your team, its qualifications, its readiness on day 1, its familiarity with tools. Ensure the criteria for fastest possible schedule are met to manage this risk. Need to motivate and support staff highly in a difficult environment. 2. Process. Managing spiral process with uncertainty and time pressure requires discipline in cutting off initial requirements, initial design, initial configuration/implementation and QA on time, to allow a second spiral. Miniature milestones, discipline to implement spiral method are needed. 3. Requirements changes, as you discover features/problems of the i2 module, problems in the master plan, data problems, changes in technology or manufacturing process, external changes forced by the market, etc. Change management process is needed, and changes must be very limited in second spiral. 4. QA. Allowing sufficient resources and time to review requirements, design, configuration, implementation, analysis. Have sufficient QA resources and ensure they do QA, not analysis or development.

5 2. Data model (35 points) Transportation Products Corp. (TPC) manufactures a wide range of products that are sold to distributors in the US and Canada. Each product is identified by a unique product ID. TPC also maintains information about the product name, size, price and weight. Each product is subject to several additional charges when sold to a customer, for example, shipping or sales tax. All of these charges are computed as a percentage of the price of the product. Each charge has a brief description. Not all charges apply to all products. Some products may have no applicable extra charges (e.g., tax free, and shipping is included). Some charges may apply to none of TPC's current products. TPC takes orders from customers for its products. Each order has a unique order number, an order date, a salesperson and a customer name. The TPC order form also displays the total cost, including extra charges, of the order, once it has been completed. Every order consists of at least one order line and can have many order lines. Each order line on the order form displays the ID of the product being ordered, the order quantity, the product price and the total sales amount for the line. Each TPC product can appear at most once on an order: there cannot be two order lines with the same product in an order. Assume that product prices do not change in this problem (unlike homework 4). You must draw a fully normalized data model that corresponds to this set of business rules. Follow these steps. You only need to turn in one drawing that includes all the elements listed in steps a e. a. Draw a box for each entity: give each an appropriate name. If there are any many to many relationships in your model, show the intermediate/associative entity explicitly in your diagram (7 points) b. List the attributes in the box for each entity (7 points) c. Indicate the primary key for each entity by placing a + or the phrase PK next to its name. (7 points) d. Draw all relationships between the entities in the model. Indicate foreign keys by placing a # or the phrase FK next to attributes that are foreign keys. (7 points) e. Indicate the cardinality of the relationship: many many, many one or oneone. Use crows foot notation; if you use another notation, define it. (7 points) To repeat: You only need to turn in one drawing that includes all the elements listed in steps a e above.

6 Draw your data model on this page.

7 3. SQL (33 points) For actual database tables and relationships created from the entities and relationships you designed in question 2 above, write SQL statements to implement the following queries. You may use either SQL 92 or implicit syntax. a. Select all products and their names that have at least one extra charge associated with them. Display only a single instance of each product. (11 points) SELECT DISTINCT ProductCharge.ProductID, ProductName FROM Product INNER JOIN ProductCharge ON Product.ProductID = ProductCharge.ProductID; b. Display the order number, product name and total price (quantity times unit price) for each of the line items in a single order. Do not display or compute extra charges. Display the line items in product name order. Use order number = 845 in your answer. (11 points) SELECT OrderNbr, ProductName, OrderQty*ProductPrice FROM Product INNER JOIN OrderDetail ON Product.ProductID = OrderDetail.ProductID WHERE OrderNbr=845 ORDER BY ProductName; c. Display all products (ID and name) that are present in more than one order. Display them only once. (11 points) SELECT Product.ProductID, ProductName FROM Product INNER JOIN OrderDetail ON Product.ProductID = OrderDetail.ProductID GROUP BY Product.ProductID, ProductName HAVING Count(Product.ProductID) > 1;