A logic chain query, is joined to a query to contribute more information based on solution found so far. Query chaining is applied at the stage when a solution has been found and only more details are required. Here is an example where two logic chain queries add payment and freight charges to customer account details:
axiom customer()
{"Marathon Marble", "Sparta"}
{"Acropolis Construction", "Athens"}
{"Agora Imports", "Sparta"}
{"Spiros Theodolites", "Milos"};
axiom fee (name, fee)
{"Marathon Marble", 61}
{"Acropolis Construction", 47}
{"Agora Imports", 49}
{"Spiros Theodolites", 57};
axiom freight (city, freight)
{"Athens", 5 }
{"Sparta", 16 }
{"Milos", 22};
template customer(name, city);
template account(name ? customer.name == name, fee);
template delivery(city ? customer.city == city, freight);
query greek_business(customer:customer)
>> (fee:account) >> (freight:delivery);
{"Marathon Marble", "Sparta"}
{"Acropolis Construction", "Athens"}
{"Agora Imports", "Sparta"}
{"Spiros Theodolites", "Milos"};
axiom fee (name, fee)
{"Marathon Marble", 61}
{"Acropolis Construction", 47}
{"Agora Imports", 49}
{"Spiros Theodolites", 57};
axiom freight (city, freight)
{"Athens", 5 }
{"Sparta", 16 }
{"Milos", 22};
template customer(name, city);
template account(name ? customer.name == name, fee);
template delivery(city ? customer.city == city, freight);
query greek_business(customer:customer)
>> (fee:account) >> (freight:delivery);