I have a table with a unary (recursive) relationship that represents a
hierarchy. With the gracious help of Mike Rylander I was able to port a
TSQL function that would traverse "up" the hierarchy to PL/SQL. Now I
need help porting the "down" the hierarchy function.
As implemented in TSQL I utilized a simple breadth first tree traversal.
I'm not sure how to replicate this in PL/SQL as I haven't figured out
how to implement the queue required for the breadth first algorithm. My
queue is declared "queue SETOF INTEGER" and I'm able to "SELECT INTO"
this variable. However when I try to delete the "current" value, I get
a syntax error. If I comment the delete out, I also get an error when I
try to fetch the "next" value from the front of the queue.
Below is the function, followed by the psql output:
CREATE OR REPLACE FUNCTION svp_getchildproviderids (INTEGER) RETURNS SETOF INTEGER AS '
DECLAREparent_provider ALIAS FOR $1;cid INTEGER;queue SETOF INTEGER;
BEGIN SELECT INTO cid count(*) FROM providers WHERE uid =parent_provider; IF cid = 0 THEN RAISE EXCEPTION
''InexistentID --> %'', parent_provider; RETURN; END IF; cid := parent_provider; LOOP EXIT WHEN cid IS
NULL; RETURN NEXT cid; SELECT INTO queue uid FROM providers WHERE parent_id = cid; DELETE FROM queue
WHEREqueue.queue = cid; SELECT INTO cid * FROM queue LIMIT 1; END LOOP; RETURN;
END;' LANGUAGE 'plpgsql';
sp_demo_505=# select * from svp_getchildproviderids(1);
ERROR: syntax error at or near "$1" at character 14
CONTEXT: PL/pgSQL function "svp_getchildproviderids" line 16 at SQL
statement
--