symmetric relations: replace bogus rql2sql translation by a hook
The hook ensures X r Y => Y r X iff r is symmetric.
The rql-no-hook data importer receives a small amendment but note
that:
* there exist no test for it
* its actual semantics are undefined
Hence we cannot prove this hunk breaks nothing, because we cannot
prove anything.
Closes #3259713.
for eschema in schema.entities():
if not (eschema.final or 'cw_source' in eschema.subjrels):
add_relation_definition(eschema.type, 'cw_source', 'CWSource', ask_confirm=False)
sql('INSERT INTO cw_source_relation(eid_from, eid_to) '
'SELECT e.eid,s.cw_eid FROM entities as e, cw_CWSource as s '
'WHERE s.cw_name=e.source AND NOT EXISTS(SELECT 1 FROM cw_source_relation WHERE eid_from=e.eid AND eid_to=s.cw_eid)')
commit()