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Neil Conway
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Support for MOVE in PL/PgSQL. Initial patch from Magnus, some improvements
by Pavel Stehule, and reviewed by Neil Conway.
1 parent f2321a3 commit 8690ebc

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-47
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8 files changed

+226
-47
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‎doc/src/sgml/plpgsql.sgml

Lines changed: 55 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1,4 +1,4 @@
1-
<!-- $PostgreSQL: pgsql/doc/src/sgml/plpgsql.sgml,v 1.108 2007/04/28 23:54:58 neilc Exp $ -->
1+
<!-- $PostgreSQL: pgsql/doc/src/sgml/plpgsql.sgml,v 1.109 2007/04/29 01:21:08 neilc Exp $ -->
22

33
<chapter id="plpgsql">
44
<title><application>PL/pgSQL</application> - <acronym>SQL</acronym> Procedural Language</title>
@@ -1522,6 +1522,13 @@ GET DIAGNOSTICS integer_var = ROW_COUNT;
15221522
true if it returns a row, false if no row is returned.
15231523
</para>
15241524
</listitem>
1525+
<listitem>
1526+
<para>
1527+
A <command>MOVE</> statement sets <literal>FOUND</literal>
1528+
true if it successfully repositions the cursor, false otherwise.
1529+
</para>
1530+
</listitem>
1531+
15251532
<listitem>
15261533
<para>
15271534
A <command>FOR</> statement sets <literal>FOUND</literal> true
@@ -2562,6 +2569,53 @@ FETCH curs1 INTO rowvar;
25622569
FETCH curs2 INTO foo, bar, baz;
25632570
FETCH LAST FROM curs3 INTO x, y;
25642571
FETCH RELATIVE -2 FROM curs4 INTO x;
2572+
</programlisting>
2573+
</para>
2574+
</sect3>
2575+
2576+
<sect3>
2577+
<title><literal>MOVE</></title>
2578+
2579+
<synopsis>
2580+
MOVE <optional> <replaceable>direction</replaceable> { FROM | IN } </optional> <replaceable>cursor</replaceable>;
2581+
</synopsis>
2582+
2583+
<para>
2584+
<command>MOVE</command> repositions a cursor without retrieving
2585+
any data. <command>MOVE</command> works exactly like the
2586+
<command>FETCH</command> command, except it only positions the
2587+
cursor and does not return rows. As with <command>SELECT
2588+
INTO</command>, the special variable <literal>FOUND</literal> can
2589+
be checked to see whether the cursor was successfully
2590+
repositioned or not.
2591+
</para>
2592+
2593+
<para>
2594+
The <replaceable>direction</replaceable> clause can be any of the
2595+
variants allowed in the SQL <xref linkend="sql-move"
2596+
endterm="sql-move-title"> command except the ones that can move by
2597+
more than one row; namely, it can be
2598+
<literal>NEXT</>,
2599+
<literal>PRIOR</>,
2600+
<literal>FIRST</>,
2601+
<literal>LAST</>,
2602+
<literal>ABSOLUTE</> <replaceable>count</replaceable>,
2603+
<literal>RELATIVE</> <replaceable>count</replaceable>,
2604+
<literal>FORWARD</>, or
2605+
<literal>BACKWARD</>.
2606+
Omitting <replaceable>direction</replaceable> is the same
2607+
as specifying <literal>NEXT</>.
2608+
<replaceable>direction</replaceable> values that require moving
2609+
backward are likely to fail unless the cursor was declared or opened
2610+
with the <literal>SCROLL</> option.
2611+
</para>
2612+
2613+
<para>
2614+
Examples:
2615+
<programlisting>
2616+
MOVE curs1;
2617+
MOVE LAST FROM curs3;
2618+
MOVE RELATIVE -2 FROM curs4;
25652619
</programlisting>
25662620
</para>
25672621
</sect3>

‎src/pl/plpgsql/src/gram.y

Lines changed: 18 additions & 2 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 1.101 2007/04/28 23:54:59 neilc Exp $
12+
* $PostgreSQL: pgsql/src/pl/plpgsql/src/gram.y,v 1.102 2007/04/29 01:21:09 neilc Exp $
1313
*
1414
*-------------------------------------------------------------------------
1515
*/
@@ -125,7 +125,7 @@ static void check_labels(const char *start_label,
125125
%type <stmt> stmt_assign stmt_if stmt_loop stmt_while stmt_exit
126126
%type <stmt> stmt_return stmt_raise stmt_execsql stmt_execsql_insert
127127
%type <stmt> stmt_dynexecute stmt_for stmt_perform stmt_getdiag
128-
%type <stmt> stmt_open stmt_fetch stmt_close stmt_null
128+
%type <stmt> stmt_open stmt_fetch stmt_move stmt_close stmt_null
129129

130130
%type <list> proc_exceptions
131131
%type <exception_block> exception_sect
@@ -179,6 +179,7 @@ static void check_labels(const char *start_label,
179179
%token K_IS
180180
%token K_LOG
181181
%token K_LOOP
182+
%token K_MOVE
182183
%token K_NEXT
183184
%token K_NOSCROLL
184185
%token K_NOT
@@ -635,6 +636,8 @@ proc_stmt : pl_block ';'
635636
{ $$ = $1; }
636637
| stmt_fetch
637638
{ $$ = $1; }
639+
| stmt_move
640+
{ $$ = $1; }
638641
| stmt_close
639642
{ $$ = $1; }
640643
| stmt_null
@@ -1478,6 +1481,19 @@ stmt_fetch : K_FETCH lno opt_fetch_direction cursor_variable K_INTO
14781481
fetch->rec = rec;
14791482
fetch->row = row;
14801483
fetch->curvar = $4->varno;
1484+
fetch->is_move = false;
1485+
1486+
$$ = (PLpgSQL_stmt *)fetch;
1487+
}
1488+
;
1489+
1490+
stmt_move : K_MOVE lno opt_fetch_direction cursor_variable ';'
1491+
{
1492+
PLpgSQL_stmt_fetch *fetch = $3;
1493+
1494+
fetch->lineno = $2;
1495+
fetch->curvar = $4->varno;
1496+
fetch->is_move = true;
14811497

14821498
$$ = (PLpgSQL_stmt *)fetch;
14831499
}

‎src/pl/plpgsql/src/pl_exec.c

Lines changed: 44 additions & 32 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_exec.c,v 1.195 2007/04/19 16:33:24 tgl Exp $
11+
* $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_exec.c,v 1.196 2007/04/29 01:21:09 neilc Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -3114,7 +3114,8 @@ exec_stmt_open(PLpgSQL_execstate *estate, PLpgSQL_stmt_open *stmt)
31143114

31153115

31163116
/* ----------
3117-
* exec_stmt_fetch Fetch from a cursor into a target
3117+
* exec_stmt_fetch Fetch from a cursor into a target, or just
3118+
* move the current position of the cursor
31183119
* ----------
31193120
*/
31203121
static int
@@ -3163,46 +3164,57 @@ exec_stmt_fetch(PLpgSQL_execstate *estate, PLpgSQL_stmt_fetch *stmt)
31633164
exec_eval_cleanup(estate);
31643165
}
31653166

3166-
/* ----------
3167-
* Determine if we fetch into a record or a row
3168-
* ----------
3169-
*/
3170-
if (stmt->rec != NULL)
3171-
rec = (PLpgSQL_rec *) (estate->datums[stmt->rec->recno]);
3172-
else if (stmt->row != NULL)
3173-
row = (PLpgSQL_row *) (estate->datums[stmt->row->rowno]);
3174-
else
3175-
elog(ERROR, "unsupported target");
3167+
if (!stmt->is_move)
3168+
{
3169+
/* ----------
3170+
* Determine if we fetch into a record or a row
3171+
* ----------
3172+
*/
3173+
if (stmt->rec != NULL)
3174+
rec = (PLpgSQL_rec *) (estate->datums[stmt->rec->recno]);
3175+
else if (stmt->row != NULL)
3176+
row = (PLpgSQL_row *) (estate->datums[stmt->row->rowno]);
3177+
else
3178+
elog(ERROR, "unsupported target");
31763179

3177-
/* ----------
3178-
* Fetch 1 tuple from the cursor
3179-
* ----------
3180-
*/
3181-
SPI_scroll_cursor_fetch(portal, stmt->direction, how_many);
3182-
tuptab = SPI_tuptable;
3183-
n = SPI_processed;
3180+
/* ----------
3181+
* Fetch 1 tuple from the cursor
3182+
* ----------
3183+
*/
3184+
SPI_scroll_cursor_fetch(portal, stmt->direction, how_many);
3185+
tuptab = SPI_tuptable;
3186+
n = SPI_processed;
31843187

3185-
/* ----------
3186-
* Set the target and the global FOUND variable appropriately.
3187-
* ----------
3188-
*/
3189-
if (n == 0)
3190-
{
3191-
exec_move_row(estate, rec, row, NULL, tuptab->tupdesc);
3192-
exec_set_found(estate, false);
3188+
/* ----------
3189+
* Set the target and the global FOUND variable appropriately.
3190+
* ----------
3191+
*/
3192+
if (n == 0)
3193+
{
3194+
exec_move_row(estate, rec, row, NULL, tuptab->tupdesc);
3195+
exec_set_found(estate, false);
3196+
}
3197+
else
3198+
{
3199+
exec_move_row(estate, rec, row, tuptab->vals[0], tuptab->tupdesc);
3200+
exec_set_found(estate, true);
3201+
}
3202+
3203+
SPI_freetuptable(tuptab);
31933204
}
31943205
else
31953206
{
3196-
exec_move_row(estate, rec, row, tuptab->vals[0], tuptab->tupdesc);
3197-
exec_set_found(estate, true);
3198-
}
3207+
/* Move the cursor */
3208+
SPI_scroll_cursor_move(portal, stmt->direction, how_many);
3209+
n = SPI_processed;
31993210

3200-
SPI_freetuptable(tuptab);
3211+
/* Set the global FOUND variable appropriately. */
3212+
exec_set_found(estate, n != 0);
3213+
}
32013214

32023215
return PLPGSQL_RC_OK;
32033216
}
32043217

3205-
32063218
/* ----------
32073219
* exec_stmt_close Close a cursor
32083220
* ----------

‎src/pl/plpgsql/src/pl_funcs.c

Lines changed: 54 additions & 9 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_funcs.c,v 1.58 2007/03/18 05:36:49 neilc Exp $
11+
* $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_funcs.c,v 1.59 2007/04/29 01:21:09 neilc Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -493,6 +493,7 @@ static void dump_dynfors(PLpgSQL_stmt_dynfors *stmt);
493493
static void dump_getdiag(PLpgSQL_stmt_getdiag *stmt);
494494
static void dump_open(PLpgSQL_stmt_open *stmt);
495495
static void dump_fetch(PLpgSQL_stmt_fetch *stmt);
496+
static void dump_cursor_direction(PLpgSQL_stmt_fetch *stmt);
496497
static void dump_close(PLpgSQL_stmt_close *stmt);
497498
static void dump_perform(PLpgSQL_stmt_perform *stmt);
498499
static void dump_expr(PLpgSQL_expr *expr);
@@ -761,21 +762,64 @@ static void
761762
dump_fetch(PLpgSQL_stmt_fetch *stmt)
762763
{
763764
dump_ind();
764-
printf("FETCH curvar=%d\n", stmt->curvar);
765+
766+
if (!stmt->is_move)
767+
{
768+
printf("FETCH curvar=%d\n", stmt->curvar);
769+
dump_cursor_direction(stmt);
765770

771+
dump_indent += 2;
772+
if (stmt->rec != NULL)
773+
{
774+
dump_ind();
775+
printf(" target = %d %s\n", stmt->rec->recno, stmt->rec->refname);
776+
}
777+
if (stmt->row != NULL)
778+
{
779+
dump_ind();
780+
printf(" target = %d %s\n", stmt->row->rowno, stmt->row->refname);
781+
}
782+
dump_indent -= 2;
783+
}
784+
else
785+
{
786+
printf("MOVE curvar=%d\n", stmt->curvar);
787+
dump_cursor_direction(stmt);
788+
}
789+
}
790+
791+
static void
792+
dump_cursor_direction(PLpgSQL_stmt_fetch *stmt)
793+
{
766794
dump_indent += 2;
767-
if (stmt->rec != NULL)
795+
dump_ind();
796+
switch (stmt->direction)
768797
{
769-
dump_ind();
770-
printf(" target = %d %s\n", stmt->rec->recno, stmt->rec->refname);
798+
case FETCH_FORWARD:
799+
printf(" FORWARD ");
800+
break;
801+
case FETCH_BACKWARD:
802+
printf(" BACKWARD ");
803+
break;
804+
case FETCH_ABSOLUTE:
805+
printf(" ABSOLUTE ");
806+
break;
807+
case FETCH_RELATIVE:
808+
printf(" RELATIVE ");
809+
break;
810+
default:
811+
printf("??? unknown cursor direction %d", stmt->direction);
771812
}
772-
if (stmt->row != NULL)
813+
814+
if (stmt->expr)
773815
{
774-
dump_ind();
775-
printf(" target = %d %s\n", stmt->row->rowno, stmt->row->refname);
816+
dump_expr(stmt->expr);
817+
printf("\n");
776818
}
819+
else
820+
printf("%d\n", stmt->how_many);
821+
777822
dump_indent -= 2;
778-
779823
}
780824

781825
static void
@@ -1067,3 +1111,4 @@ plpgsql_dumptree(PLpgSQL_function *func)
10671111
printf("\nEnd of execution tree of function %s\n\n", func->fn_name);
10681112
fflush(stdout);
10691113
}
1114+

‎src/pl/plpgsql/src/plpgsql.h

Lines changed: 3 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $PostgreSQL: pgsql/src/pl/plpgsql/src/plpgsql.h,v 1.87 2007/04/16 17:21:23 tgl Exp $
11+
* $PostgreSQL: pgsql/src/pl/plpgsql/src/plpgsql.h,v 1.88 2007/04/29 01:21:09 neilc Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -446,7 +446,7 @@ typedef struct
446446

447447

448448
typedef struct
449-
{ /* FETCH statement */
449+
{ /* FETCH or MOVE statement */
450450
int cmd_type;
451451
int lineno;
452452
PLpgSQL_rec *rec; /* target, as record or row */
@@ -455,6 +455,7 @@ typedef struct
455455
FetchDirection direction; /* fetch direction */
456456
int how_many; /* count, if constant (expr is NULL) */
457457
PLpgSQL_expr *expr; /* count, if expression */
458+
bool is_move; /* is this a fetch or move? */
458459
} PLpgSQL_stmt_fetch;
459460

460461

‎src/pl/plpgsql/src/scan.l

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -9,7 +9,7 @@
99
*
1010
*
1111
* IDENTIFICATION
12-
* $PostgreSQL: pgsql/src/pl/plpgsql/src/scan.l,v 1.56 2007/04/16 17:21:23 tgl Exp $
12+
* $PostgreSQL: pgsql/src/pl/plpgsql/src/scan.l,v 1.57 2007/04/29 01:21:09 neilc Exp $
1313
*
1414
*-------------------------------------------------------------------------
1515
*/
@@ -142,6 +142,7 @@ into { return K_INTO; }
142142
is { return K_IS; }
143143
log { return K_LOG; }
144144
loop { return K_LOOP; }
145+
move { return K_MOVE; }
145146
next { return K_NEXT; }
146147
no{space}+scroll { return K_NOSCROLL; }
147148
not { return K_NOT; }

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