The XDb2 script below models a single and a daily sale of products at
WalMarts in different cities. Each product has multiple classifications
and properties such as manufacturer, flavor, cost, etc. The individual
sale records date/time, price, quantity, customer, etc. A complex query
to find the individual sale is shown near end of script. See
www.xdb2.com/Example/Ex115.asp for details.


// Create classes to categorize things
CREATE *store.item ~in = dir;
CREATE *city.item ~in = dir;
CREATE *state.item ~in = dir;

CREATE *product.item ~in = dir;
CREATE *produce.item ~in = dir;
CREATE *medicine.item ~in = dir;
CREATE *headache remedy.item ~in = dir;
CREATE *cold medicine.item ~in = dir;

CREATE *mfg.item ~in = dir;
CREATE *flavor.item ~in = dir;
CREATE *cost.item ~in = dir;
CREATE *price.item ~in = dir;

CREATE *sale.item ~in = dir;
CREATE *daily sale.item ~in = dir;
CREATE *individual sale.item ~in = dir;
CREATE *date.item ~in = dir;
CREATE *time.item ~in = dir;
CREATE *qty.item ~in = dir;
CREATE *memo.item ~in = dir;

// Create Asprin
CREATE *asprin.cls = product;
CREATE asprin.cls = medicine;
CREATE asprin.cls = headache remedy;
CREATE asprin.mfg = +bayer;
CREATE asprin.cost = +1.00;

// Create Tylenol
CREATE *tylenol.cls = product;
CREATE tylenol.cls = medicine;
CREATE tylenol.cls = cold medicine;
CREATE tylenol.cost = +2.00;

// Create Nyquil
CREATE *nyquil.cls = product;
CREATE nyquil.cls = medicine;
CREATE nyquil.cls = headache remedy;
CREATE nyquil.cls = cold medicine;
CREATE nyquil.mfg = +pfizer;
CREATE nyquil.flavor = +cherry;
CREATE nyquil.cost = +3.00;

// Create Garlic
CREATE *garlic.cls = product;
CREATE garlic.cls = produce;
CREATE garlic.cls = headache remedy;
CREATE garlic.cls = cold medicine;
CREATE garlic.cost = +4.00;

// Create Ginger
CREATE *ginger.cls = product;
CREATE ginger.cls = produce;
CREATE ginger.cls = cold medicine;
CREATE ginger.cost = +5.00;

// Create classes for persons and properties
CREATE *person.item ~in = dir;
CREATE *mgr.item ~in = dir;
CREATE *customer.item ~in = dir;
CREATE *gender.item ~in = dir;
CREATE *age.item ~in = dir;
CREATE *ss#.item ~in = dir;

// Create John
CREATE *john.cls = person;
CREATE john.cls = mgr;

// Create Mary
CREATE *mary.cls = person;
CREATE mary.cls = mgr;

// Create John likes Mary
CREATE *like.cls = verb;
CREATE john.like = mary;

// Create Bob
CREATE *bob.cls = person;
CREATE bob.cls = customer;
CREATE bob.gender = +male;
CREATE bob.age = +35;
CREATE bob."ss#" = +111-22-3333;


// Create Cooperstown
CREATE *cooperstown.cls = city;
CREATE cooperstown.state = +new york;

// Create Chicago
CREATE *chicago.cls = city;
CREATE chicago.state = +illinois;

// Create Walmart #1 managed by John
CREATE *walmart.cls = store;
CREATE *walmart #1.cls = walmart;
CREATE walmart #1.city = cooperstown;
CREATE walmart #1.mgr = john;

// Create Walmart #2 managed by Mary
CREATE *walmart #2.cls = walmart;
CREATE walmart #2.city = chicago;
CREATE walmart #2.mgr = mary;


// Record a daily sale of 179 units of Nyquil
// on Dec 3rd at Walmart #1
CREATE *;
CREATE it.cls = sale;
CREATE it.cls = daily sale;
CREATE it.store = walmart #1;
CREATE it.date = +12/3/04;
CREATE it.product = nyquil;
CREATE it.qty = +179;

// Record an individual sales of Nyquil
// on 12/3/04 12:34:45 at Walmart #2 to Bob.
CREATE *;
CREATE it.cls = sale;
CREATE it.cls = individual sale;
CREATE it.store = walmart #2;
CREATE it.date = +12/3/04;
CREATE it.time = +12:34:45;
CREATE it.product = nyquil;
CREATE it.price = +3.19;
CREATE it.qty = +1;
CREATE it.customer = (%.cls=person & %.cls=customer & %.name=bob &
%.age=35 & %."ss#"=111-22-3333);
CREATE it.memo = +an alien fell thru ceiling;

// Find a sale at a store in illinois
// where the store manager is liked by another manager named john
// and the cold medicine product sold was mfgd by pfizer
// and sold to a person who is male.
// Finds sale of Nyquil to Bob at Walmart #2.
SELECT %.cls=sale & %.store=(%.city=(%.state=illinois) &
%.mgr=((%.cls=mgr & %.name=john).like=%)) & %.product=(%.cls=cold
medicine & %.mfg=pfizer) & %.customer=(%.gender=male);