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Make plpgsql support FOR over a query specified by a cursor declaration,
for improved compatibility with Oracle. Pavel Stehule, with some fixes by me.
1 parent 2604359 commit 347dd6a

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8 files changed

+934
-555
lines changed

8 files changed

+934
-555
lines changed

‎doc/src/sgml/plpgsql.sgml

Lines changed: 163 additions & 110 deletions
Large diffs are not rendered by default.

‎src/pl/plpgsql/src/gram.y

Lines changed: 144 additions & 89 deletions
Original file line numberDiff line numberDiff line change
@@ -9,7 +9,7 @@
99
*
1010
*
1111
* IDENTIFICATION
12-
* $PostgreSQL: pgsql/src/pl/plpgsql/src/gram.y,v 1.109 2008/04/01 03:51:09 tgl Exp $
12+
* $PostgreSQL: pgsql/src/pl/plpgsql/src/gram.y,v 1.110 2008/04/06 23:43:29 tgl Exp $
1313
*
1414
*-------------------------------------------------------------------------
1515
*/
@@ -50,6 +50,8 @@ static void plpgsql_sql_error_callback(void *arg);
5050
static char *check_label(const char *yytxt);
5151
static void check_labels(const char *start_label,
5252
const char *end_label);
53+
static PLpgSQL_expr *read_cursor_args(PLpgSQL_var *cursor,
54+
int until, const char *expected);
5355

5456
%}
5557

@@ -861,21 +863,15 @@ stmt_for : opt_block_label K_FOR for_control loop_body
861863
new->body = $4.stmts;
862864
$$ = (PLpgSQL_stmt *) new;
863865
}
864-
else if ($3->cmd_type == PLPGSQL_STMT_FORS)
865-
{
866-
PLpgSQL_stmt_fors *new;
867-
868-
new = (PLpgSQL_stmt_fors *) $3;
869-
new->label = $1;
870-
new->body = $4.stmts;
871-
$$ = (PLpgSQL_stmt *) new;
872-
}
873866
else
874867
{
875-
PLpgSQL_stmt_dynfors *new;
868+
PLpgSQL_stmt_forq *new;
876869

877-
Assert($3->cmd_type == PLPGSQL_STMT_DYNFORS);
878-
new = (PLpgSQL_stmt_dynfors *) $3;
870+
Assert($3->cmd_type == PLPGSQL_STMT_FORS ||
871+
$3->cmd_type == PLPGSQL_STMT_FORC ||
872+
$3->cmd_type == PLPGSQL_STMT_DYNFORS);
873+
/* forq is the common supertype of all three */
874+
new = (PLpgSQL_stmt_forq *) $3;
879875
new->label = $1;
880876
new->body = $4.stmts;
881877
$$ = (PLpgSQL_stmt *) new;
@@ -892,9 +888,9 @@ for_control :
892888
{
893889
int tok = yylex();
894890

895-
/* Simple case: EXECUTE is a dynamic FOR loop */
896891
if (tok == K_EXECUTE)
897892
{
893+
/* EXECUTE means it's a dynamic FOR loop */
898894
PLpgSQL_stmt_dynfors *new;
899895
PLpgSQL_expr *expr;
900896
int term;
@@ -942,6 +938,47 @@ for_control :
942938

943939
$$ = (PLpgSQL_stmt *) new;
944940
}
941+
else if (tok == T_SCALAR &&
942+
yylval.scalar->dtype == PLPGSQL_DTYPE_VAR &&
943+
((PLpgSQL_var *) yylval.scalar)->datatype->typoid == REFCURSOROID)
944+
{
945+
/* It's FOR var IN cursor */
946+
PLpgSQL_stmt_forc *new;
947+
PLpgSQL_var *cursor = (PLpgSQL_var *) yylval.scalar;
948+
char *varname;
949+
950+
new = (PLpgSQL_stmt_forc *) palloc0(sizeof(PLpgSQL_stmt_forc));
951+
new->cmd_type = PLPGSQL_STMT_FORC;
952+
new->lineno = $1;
953+
954+
new->curvar = cursor->varno;
955+
956+
/* Should have had a single variable name */
957+
plpgsql_error_lineno = $2.lineno;
958+
if ($2.scalar && $2.row)
959+
ereport(ERROR,
960+
(errcode(ERRCODE_SYNTAX_ERROR),
961+
errmsg("cursor FOR loop must have just one target variable")));
962+
963+
/* create loop's private RECORD variable */
964+
plpgsql_convert_ident($2.name, &varname, 1);
965+
new->rec = plpgsql_build_record(varname,
966+
$2.lineno,
967+
true);
968+
969+
/* can't use an unbound cursor this way */
970+
if (cursor->cursor_explicit_expr == NULL)
971+
ereport(ERROR,
972+
(errcode(ERRCODE_SYNTAX_ERROR),
973+
errmsg("cursor FOR loop must use a bound cursor variable")));
974+
975+
/* collect cursor's parameters if any */
976+
new->argquery = read_cursor_args(cursor,
977+
K_LOOP,
978+
"LOOP");
979+
980+
$$ = (PLpgSQL_stmt *) new;
981+
}
945982
else
946983
{
947984
PLpgSQL_expr *expr1;
@@ -1412,81 +1449,8 @@ stmt_open : K_OPEN lno cursor_variable
14121449
}
14131450
else
14141451
{
1415-
if ($3->cursor_explicit_argrow >= 0)
1416-
{
1417-
char *cp;
1418-
1419-
tok = yylex();
1420-
if (tok != '(')
1421-
{
1422-
plpgsql_error_lineno = plpgsql_scanner_lineno();
1423-
ereport(ERROR,
1424-
(errcode(ERRCODE_SYNTAX_ERROR),
1425-
errmsg("cursor \"%s\" has arguments",
1426-
$3->refname)));
1427-
}
1428-
1429-
/*
1430-
* Push back the '(', else read_sql_stmt
1431-
* will complain about unbalanced parens.
1432-
*/
1433-
plpgsql_push_back_token(tok);
1434-
1435-
new->argquery = read_sql_stmt("SELECT ");
1436-
1437-
/*
1438-
* Now remove the leading and trailing parens,
1439-
* because we want "select 1, 2", not
1440-
* "select (1, 2)".
1441-
*/
1442-
cp = new->argquery->query;
1443-
1444-
if (strncmp(cp, "SELECT", 6) != 0)
1445-
{
1446-
plpgsql_error_lineno = plpgsql_scanner_lineno();
1447-
/* internal error */
1448-
elog(ERROR, "expected \"SELECT (\", got \"%s\"",
1449-
new->argquery->query);
1450-
}
1451-
cp += 6;
1452-
while (*cp == ' ') /* could be more than 1 space here */
1453-
cp++;
1454-
if (*cp != '(')
1455-
{
1456-
plpgsql_error_lineno = plpgsql_scanner_lineno();
1457-
/* internal error */
1458-
elog(ERROR, "expected \"SELECT (\", got \"%s\"",
1459-
new->argquery->query);
1460-
}
1461-
*cp = ' ';
1462-
1463-
cp += strlen(cp) - 1;
1464-
1465-
if (*cp != ')')
1466-
yyerror("expected \")\"");
1467-
*cp = '\0';
1468-
}
1469-
else
1470-
{
1471-
tok = yylex();
1472-
if (tok == '(')
1473-
{
1474-
plpgsql_error_lineno = plpgsql_scanner_lineno();
1475-
ereport(ERROR,
1476-
(errcode(ERRCODE_SYNTAX_ERROR),
1477-
errmsg("cursor \"%s\" has no arguments",
1478-
$3->refname)));
1479-
}
1480-
1481-
if (tok != ';')
1482-
{
1483-
plpgsql_error_lineno = plpgsql_scanner_lineno();
1484-
ereport(ERROR,
1485-
(errcode(ERRCODE_SYNTAX_ERROR),
1486-
errmsg("syntax error at \"%s\"",
1487-
yytext)));
1488-
}
1489-
}
1452+
/* predefined cursor query, so read args */
1453+
new->argquery = read_cursor_args($3, ';', ";");
14901454
}
14911455

14921456
$$ = (PLpgSQL_stmt *)new;
@@ -2578,6 +2542,97 @@ check_labels(const char *start_label, const char *end_label)
25782542
}
25792543
}
25802544

2545+
/*
2546+
* Read the arguments (if any) for a cursor, followed by the until token
2547+
*
2548+
* If cursor has no args, just swallow the until token and return NULL.
2549+
* If it does have args, we expect to see "( expr [, expr ...] )" followed
2550+
* by the until token. Consume all that and return a SELECT query that
2551+
* evaluates the expression(s) (without the outer parens).
2552+
*/
2553+
static PLpgSQL_expr *
2554+
read_cursor_args(PLpgSQL_var *cursor, int until, const char *expected)
2555+
{
2556+
PLpgSQL_expr *expr;
2557+
int tok;
2558+
char *cp;
2559+
2560+
tok = yylex();
2561+
if (cursor->cursor_explicit_argrow < 0)
2562+
{
2563+
/* No arguments expected */
2564+
if (tok == '(')
2565+
{
2566+
plpgsql_error_lineno = plpgsql_scanner_lineno();
2567+
ereport(ERROR,
2568+
(errcode(ERRCODE_SYNTAX_ERROR),
2569+
errmsg("cursor \"%s\" has no arguments",
2570+
cursor->refname)));
2571+
}
2572+
2573+
if (tok != until)
2574+
{
2575+
plpgsql_error_lineno = plpgsql_scanner_lineno();
2576+
ereport(ERROR,
2577+
(errcode(ERRCODE_SYNTAX_ERROR),
2578+
errmsg("syntax error at \"%s\"",
2579+
yytext)));
2580+
}
2581+
2582+
return NULL;
2583+
}
2584+
2585+
/* Else better provide arguments */
2586+
if (tok != '(')
2587+
{
2588+
plpgsql_error_lineno = plpgsql_scanner_lineno();
2589+
ereport(ERROR,
2590+
(errcode(ERRCODE_SYNTAX_ERROR),
2591+
errmsg("cursor \"%s\" has arguments",
2592+
cursor->refname)));
2593+
}
2594+
2595+
/*
2596+
* Push back the '(', else plpgsql_read_expression
2597+
* will complain about unbalanced parens.
2598+
*/
2599+
plpgsql_push_back_token(tok);
2600+
2601+
expr = plpgsql_read_expression(until, expected);
2602+
2603+
/*
2604+
* Now remove the leading and trailing parens,
2605+
* because we want "SELECT 1, 2", not "SELECT (1, 2)".
2606+
*/
2607+
cp = expr->query;
2608+
2609+
if (strncmp(cp, "SELECT", 6) != 0)
2610+
{
2611+
plpgsql_error_lineno = plpgsql_scanner_lineno();
2612+
/* internal error */
2613+
elog(ERROR, "expected \"SELECT (\", got \"%s\"", expr->query);
2614+
}
2615+
cp += 6;
2616+
while (*cp == ' ') /* could be more than 1 space here */
2617+
cp++;
2618+
if (*cp != '(')
2619+
{
2620+
plpgsql_error_lineno = plpgsql_scanner_lineno();
2621+
/* internal error */
2622+
elog(ERROR, "expected \"SELECT (\", got \"%s\"", expr->query);
2623+
}
2624+
*cp = ' ';
2625+
2626+
cp += strlen(cp) - 1;
2627+
2628+
if (*cp != ')')
2629+
yyerror("expected \")\"");
2630+
*cp = '\0';
2631+
2632+
return expr;
2633+
}
2634+
2635+
25812636
/* Needed to avoid conflict between different prefix settings: */
25822637
#undef yylex
25832638

‎src/pl/plpgsql/src/pl_comp.c

Lines changed: 27 additions & 30 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_comp.c,v 1.123 2008/03/27 03:57:34 tgl Exp $
11+
* $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_comp.c,v 1.124 2008/04/06 23:43:29 tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -575,25 +575,11 @@ do_compile(FunctionCallInfo fcinfo,
575575
errhint("You probably want to use TG_NARGS and TG_ARGV instead.")));
576576

577577
/* Add the record for referencing NEW */
578-
rec = palloc0(sizeof(PLpgSQL_rec));
579-
rec->dtype = PLPGSQL_DTYPE_REC;
580-
rec->refname = pstrdup("new");
581-
rec->tup = NULL;
582-
rec->tupdesc = NULL;
583-
rec->freetup = false;
584-
plpgsql_adddatum((PLpgSQL_datum *) rec);
585-
plpgsql_ns_additem(PLPGSQL_NSTYPE_REC, rec->recno, rec->refname);
578+
rec = plpgsql_build_record("new", 0, true);
586579
function->new_varno = rec->recno;
587580

588581
/* Add the record for referencing OLD */
589-
rec = palloc0(sizeof(PLpgSQL_rec));
590-
rec->dtype = PLPGSQL_DTYPE_REC;
591-
rec->refname = pstrdup("old");
592-
rec->tup = NULL;
593-
rec->tupdesc = NULL;
594-
rec->freetup = false;
595-
plpgsql_adddatum((PLpgSQL_datum *) rec);
596-
plpgsql_ns_additem(PLPGSQL_NSTYPE_REC, rec->recno, rec->refname);
582+
rec = plpgsql_build_record("old", 0, true);
597583
function->old_varno = rec->recno;
598584

599585
/* Add the variable tg_name */
@@ -1481,21 +1467,10 @@ plpgsql_build_variable(const char *refname, int lineno, PLpgSQL_type *dtype,
14811467
}
14821468
case PLPGSQL_TTYPE_REC:
14831469
{
1484-
/*
1485-
* "record" type -- build a variable-contents record variable
1486-
*/
1470+
/* "record" type -- build a record variable */
14871471
PLpgSQL_rec *rec;
14881472

1489-
rec = palloc0(sizeof(PLpgSQL_rec));
1490-
rec->dtype = PLPGSQL_DTYPE_REC;
1491-
rec->refname = pstrdup(refname);
1492-
rec->lineno = lineno;
1493-
1494-
plpgsql_adddatum((PLpgSQL_datum *) rec);
1495-
if (add2namespace)
1496-
plpgsql_ns_additem(PLPGSQL_NSTYPE_REC,
1497-
rec->recno,
1498-
refname);
1473+
rec = plpgsql_build_record(refname, lineno, add2namespace);
14991474
result = (PLpgSQL_variable *) rec;
15001475
break;
15011476
}
@@ -1515,6 +1490,28 @@ plpgsql_build_variable(const char *refname, int lineno, PLpgSQL_type *dtype,
15151490
return result;
15161491
}
15171492

1493+
/*
1494+
* Build empty named record variable, and optionally add it to namespace
1495+
*/
1496+
PLpgSQL_rec *
1497+
plpgsql_build_record(const char *refname, int lineno, bool add2namespace)
1498+
{
1499+
PLpgSQL_rec *rec;
1500+
1501+
rec = palloc0(sizeof(PLpgSQL_rec));
1502+
rec->dtype = PLPGSQL_DTYPE_REC;
1503+
rec->refname = pstrdup(refname);
1504+
rec->lineno = lineno;
1505+
rec->tup = NULL;
1506+
rec->tupdesc = NULL;
1507+
rec->freetup = false;
1508+
plpgsql_adddatum((PLpgSQL_datum *) rec);
1509+
if (add2namespace)
1510+
plpgsql_ns_additem(PLPGSQL_NSTYPE_REC, rec->recno, rec->refname);
1511+
1512+
return rec;
1513+
}
1514+
15181515
/*
15191516
* Build a row-variable data structure given the pg_class OID.
15201517
*/

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