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Apologies, I should've been more clear. The absolute length of SQL wasn't what I was alluding to: it was the ratio of Datalog to SQL I was curious about based o

Apologies, I should've been more clear. The absolute length of SQL wasn't what I was alluding to: it was the ratio of Datalog to SQL I was curious about based on this statement in the website: > Among database theoreticians Datalog and SQL are known to be equivalent. And indeed the conversion from Datalog to SQL and back is often straightforward. I was skeptical, and indeed the sample I linked to shows 8 lines of Datalog turning into 265 lines of SQL. In defense of SQL, I note WITH RECURSIVE wasn't used.

greenavocado 3y ago
CREATE TABLE edges ( source INT, target INT ); INSERT INTO edges (source, target) SELECT generate_series as source, generate_series + 1 as target FROM generate_series(0, 999); WITH RECURSIVE path_lengths AS ( -- Base case: Direct paths from edges SELECT source, target, 1 AS distance FROM edges UNION ALL -- Recursive step: Double the path length by joining on intermediate nodes SELECT p.source, e.target, p.distance + 1 AS distance FROM path_lengths AS p JOIN edges AS e ON p.target = e.source WHERE p.distance < 256 -- Control the recursion depth (2^8=256 for C8 equivalent) ) -- Final query to select paths from source 0, similar to the logic program's final goal , final_paths AS ( SELECT source, target, MIN(distance) AS distance FROM path_lengths WHERE source = 0 GROUP BY source, target ) SELECT * FROM final_paths ORDER BY source, target; You can confirm the output matches by pasting it and clicking run here: https://extendsclass.com/postgresql-online.html https://extendsclass.com/postgresql-online.html
- ryanjshaw 3y ago
  That's really not bad. I'm looking at CozoDB for a hobby project of mine, but if Logica could produce output like this consistently I'd probably prefer it because I'm much more familiar with maintaining RDBMSs.
  - greenavocado 3y ago
    Logica didn't output that. I posted SQL equivalent to the original Logica.

greenavocado 3y ago

CREATE TABLE edges ( source INT, target INT ); INSERT INTO edges (source, target) SELECT generate_series as source, generate_series + 1 as target FROM generate_series(0, 999); WITH RECURSIVE path_lengths AS ( -- Base case: Direct paths from edges SELECT source, target, 1 AS distance FROM edges UNION ALL -- Recursive step: Double the path length by joining on intermediate nodes SELECT p.source, e.target, p.distance + 1 AS distance FROM path_lengths AS p JOIN edges AS e ON p.target = e.source WHERE p.distance < 256 -- Control the recursion depth (2^8=256 for C8 equivalent) ) -- Final query to select paths from source 0, similar to the logic program's final goal , final_paths AS ( SELECT source, target, MIN(distance) AS distance FROM path_lengths WHERE source = 0 GROUP BY source, target ) SELECT * FROM final_paths ORDER BY source, target; You can confirm the output matches by pasting it and clicking run here: https://extendsclass.com/postgresql-online.html https://extendsclass.com/postgresql-online.html

ryanjshaw 3y ago
That's really not bad. I'm looking at CozoDB for a hobby project of mine, but if Logica could produce output like this consistently I'd probably prefer it because I'm much more familiar with maintaining RDBMSs.
- greenavocado 3y ago
  Logica didn't output that. I posted SQL equivalent to the original Logica.