customer-charge.taq

$ java -jar taq.jar customer-charge

Running query customer_delivery in global scope 
customer_freight(name=Acropolis Construction, city=Athens, charge=23.99)
customer_freight(name=Marathon Marble, city=Sparta, charge=13.99)
customer_freight(name=Agora Imports, city=Sparta, charge=13.99)
customer_freight(name=Spiros Theodolites, city=Milos, charge=17.99)

Description

customer-charge.taq demonstrates a cascading query used to aggregate data from 2 different tables organized as axiom lists. The first, named “shipping”, contains freight charged for delivery to a particular city and the second, named “customer”, contains customer details. The “customer_delivery” query returns for each customer, name, city, and freight charge. The query statement expresses how to create a “customer_delivery” axiom list as shown above

query<axiom> customer_delivery(shipping:freight, customer:customer_freight)

The “freight” template simply collects the shipping data and passes it on to the next template. The “customer_freight” template picks up the freight data by using 2-part names where the first part is “freight”. The selection logic of the second template matches the freight city to the customer city:

city ? freight.city

template freight(charge, city)

template customer_freight
(

name,
city ? freight.city,
charge = freight.charge

)

query<axiom> customer_delivery(shipping:freight, customer:customer_freight)

axiom list shipping (city, charge)
{"Athens", 23.99 }
{"Sparta", 13.99 }
{"Milos", 17.99 }

axiom list customer (name, city)
{"Marathon Marble", "Sparta"}
{"Acropolis Construction", "Athens"}
{"Agora Imports", "Sparta"}
{"Spiros Theodolites", "Milos"}