Transitive closure

tc.sql

CREATE TABLE tc(a INTEGER, b INTEGER, PRIMARY KEY (a,b)); 

INSERT OR IGNORE INTO tc(a,b)
VALUES (1,2),(2,3),(3,4); 

-- repeat this query many times for naive iteration
-- path(x,z) :- path(x,y), path(y,z).
INSERT OR IGNORE INTO tc SELECT DISTINCT tc0.a, tc1.b   -- the head of the rule gives the insert and select fields  
FROM tc as tc0, tc as tc1
WHERE tc0.b = tc1.a; -- The body of the rule gives FROM and WHERE