Descriptive schema assignment

Mission: Create a structure to describe a certain category of objects for a defined audience and purpose.

This structure will consist of attributes (properties or characteristics) and associated values.

Out of the infinite universe of potential attributes, you will define a set of 10-15 that interpret the class of objects you’ve chosen in a way that facilitates the purpose you’ve identified.

Descriptive schema example

Object: Recipes, by which I mean a set of written instructions for preparing a specific dish. The preparation must be non-obvious (e.g., putting cereal into a bowl is not a recipe).

Audience and purpose: To help fledgling cooks make dishes appropriate for their level of skill

Attributes and values #1

• Knife skills required basic chopping, dicing, fine chopping, slicing, advanced cuts, butchering

• Number of ingredients• Number of pots• Prep time• Labor-intensive activities garlic crushing, ginger grating,

herb chopping• Cooking time• Level of attention required• Instruction style Sketchy, basic, detailed• Leftover potential (in number of meals)

Descriptive schema example

Object: Recipes

Audience and purpose: To help experienced cooks create a menu for entertaining

Attributes and values # 2• Meal potluck, picnic, dinner party, cookout, cocktails,

tea, brunch• Event birthday, holiday, romance, • Guests Colleagues, kids, family, chums, powers that be• Sophistication trashy, rustic, comfort, flashy, nuanced,

quaint, difficult• Cuisine Italian, Mediterranean, Chinese, Thai, Indian,

Mexican, just food• Beverage red, white, pink, beer, soft• Expense• Kitchen management Oven, one burner, two burners, three

burners, four burners, none

Rules of thumb

Avoid binary attributes (with values of Yes or No). See if these can be represented as a range of values. For a hiking trail, instead of an attribute of Paved, with values of Yes and No, use a value of Surface, with values of Dirt, Paved, Gravel, and so on.

Don’t make this harder than it is. Yes, because you need to explain how your schema is used, you need some precision in defining the scope of your set of entities, attributes, values, and so on. But don’t get hung up on a quest for comprehensiveness, or have too much fun with convoluted structures. Don’t miss the forest for the trees!

Rules of thumb

Documentation is key.Explaining your schema so that others can use it is at least as important as developing your set of attributes and values.

Really use your test cases to explore the strengths and weaknesses of your schema. If you don’t learn anything by applying your schema to a range of test cases, then you might need to try another test case!

Rules of thumb

In your design reflection, don’t just summarize what you did or tell me why your schema is good. I’d most like to hear about how the process of doing the assignment made you think.

Make sure you understand the deliverables and grading criteria. I will expect your assignment to contain the deliverables listed, and I will assign equal points to each of the listed criteria.