Re: [HACKERS] psql - add special variable to reflect the last query status - Mailing list pgsql-hackers

Hello Pavel,

+ if (success)
+ {
+ char   *ntuples = PQcmdTuples(results);
+ SetVariable(pset.vars, "ROW_COUNT", *ntuples ? ntuples : "0");
+ SetVariable(pset.vars, "ERROR", "FALSE");
+ }
+ else
+ {
+ SetVariable(pset.vars, "ROW_COUNT", "0");
+ SetVariable(pset.vars, "ERROR", "TRUE");
+ }
+}

It can be simplified

SetVariable(pset.vars, "ROW_COUNT", success ? PQcmdTuples(results) : 0);

According to the documentation, PQcmdTuples returns "" in some cases and ISTM we want "0" instead for consistency, so that it is always a number. I rejected calling PQcmdTuples twice:

  ..., success && *PQcmdTuples(results) ? PQcmdTuples(results) : "0")

Thus it makes the "if (success)" necessary for ROW_COUNT, and then it looked simpler to handle ERROR the same way.

Now if the semantics is changed to put as row count whatever comes out of the function, even if not a count, then the code could indeed be simplified as you suggest.

--
Fabien.