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bmomjianbmomjian
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Cause FETCH 1 to return the current cursor row, or zero if at
beginning/end of cursor. Have MOVE return 0/1 depending on cursor position. Matches SQL spec. Pass cursor counter from parser as a long rather than int. Doc updates.
1 parent a0fa011 commit 33f0108

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7 files changed

+56
-57
lines changed

7 files changed

+56
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lines changed

‎doc/src/sgml/ref/fetch.sgml

Lines changed: 2 additions & 26 deletions
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,5 @@
11
<!--
2-
$Header: /cvsroot/pgsql/doc/src/sgml/ref/fetch.sgml,v 1.21 2002/04/21 19:02:39 thomas Exp $
2+
$Header: /cvsroot/pgsql/doc/src/sgml/ref/fetch.sgml,v 1.22 2002/12/30 15:31:47 momjian Exp $
33
PostgreSQL documentation
44
-->
55

@@ -89,7 +89,7 @@ FETCH [ FORWARD | BACKWARD | RELATIVE ] [ <replaceable class="PARAMETER">#</repl
8989
<para>
9090
A signed integer that specifies how many rows to fetch.
9191
Note that a negative integer is equivalent to changing the sense of
92-
FORWARD and BACKWARD.
92+
FORWARD and BACKWARD. Zero re-fetches the current row.
9393
</para>
9494
</listitem>
9595
</varlistentry>
@@ -180,30 +180,6 @@ WARNING: FETCH/ABSOLUTE not supported, using RELATIVE
180180
</listitem>
181181
</varlistentry>
182182

183-
<varlistentry>
184-
<term><computeroutput>
185-
ERROR: FETCH/RELATIVE at current position is not supported
186-
</computeroutput></term>
187-
<listitem>
188-
<para>
189-
<acronym>SQL92</acronym> allows one to repetitively retrieve the cursor
190-
at its <quote>current position</quote> using the syntax
191-
<synopsis>
192-
FETCH RELATIVE 0 FROM <replaceable class="PARAMETER">cursor</replaceable>.
193-
</synopsis>
194-
</para>
195-
196-
<para>
197-
<productname>PostgreSQL</productname> does not currently support
198-
this notion; in fact the value zero is reserved to indicate that
199-
all rows should be retrieved and is equivalent to specifying the ALL keyword.
200-
If the RELATIVE keyword has been used, <productname>PostgreSQL</productname>
201-
assumes that the user intended <acronym>SQL92</acronym> behavior
202-
and returns this error message.
203-
</para>
204-
</listitem>
205-
</varlistentry>
206-
207183
</variablelist>
208184
</para>
209185
</refsect2>

‎doc/src/sgml/ref/move.sgml

Lines changed: 3 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,5 @@
11
<!--
2-
$Header: /cvsroot/pgsql/doc/src/sgml/ref/move.sgml,v 1.14 2002/11/13 00:44:08 momjian Exp $
2+
$Header: /cvsroot/pgsql/doc/src/sgml/ref/move.sgml,v 1.15 2002/12/30 15:31:47 momjian Exp $
33
PostgreSQL documentation
44
-->
55

@@ -35,8 +35,8 @@ MOVE [ <replaceable class="PARAMETER">direction</replaceable> ]
3535
Description
3636
</title>
3737
<para>
38-
<command>MOVE</command> allows a user to move cursor position a specified
39-
number of rows.
38+
<command>MOVE</command> allows a user to move the cursor position a
39+
specified number of rows.
4040
<command>MOVE</command> works like the <command>FETCH</command> command,
4141
but only positions the cursor and does not return rows.
4242
<replaceable class="PARAMETER">LAST</replaceable> moves to the end

‎src/backend/commands/portalcmds.c

Lines changed: 40 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $Header: /cvsroot/pgsql/src/backend/commands/portalcmds.c,v 1.6 2002/12/15 16:17:42 tgl Exp $
11+
* $Header: /cvsroot/pgsql/src/backend/commands/portalcmds.c,v 1.7 2002/12/30 15:31:47 momjian Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -65,7 +65,7 @@ PortalCleanup(Portal portal)
6565
void
6666
PerformPortalFetch(char *name,
6767
bool forward,
68-
int count,
68+
long count,
6969
CommandDest dest,
7070
char *completionTag)
7171
{
@@ -100,14 +100,48 @@ PerformPortalFetch(char *name,
100100
return;
101101
}
102102

103-
/* If zero count, we are done */
103+
/* If zero count, handle specially */
104104
if (count == 0)
105-
return;
105+
{
106+
bool on_row = false;
107+
108+
/* Are we sitting on a row? */
109+
oldcontext = MemoryContextSwitchTo(PortalGetHeapMemory(portal));
110+
queryDesc = PortalGetQueryDesc(portal);
111+
estate = queryDesc->estate;
112+
if (portal->atStart == false && portal->atEnd == false)
113+
on_row = true;
114+
MemoryContextSwitchTo(oldcontext);
115+
116+
if (dest == None)
117+
{
118+
/* MOVE 0 returns 0/1 based on if FETCH 0 would return a row */
119+
if (completionTag && on_row)
120+
strcpy(completionTag, "MOVE 1");
121+
return;
122+
}
123+
else
124+
{
125+
/* If we are not on a row, FETCH 0 returns nothing */
126+
if (!on_row)
127+
return;
128+
129+
/* Since we are sitting on a row, return the row */
130+
/* Back up so we can reread the row */
131+
PerformPortalFetch(name, false /* backward */, 1,
132+
None, /* throw away output */
133+
NULL /* do not modify the command tag */);
134+
135+
/* Set up to fetch one row */
136+
count = 1;
137+
forward = true;
138+
}
139+
}
106140

107141
/* Internally, zero count processes all portal rows */
108-
if (count == INT_MAX)
142+
if (count == LONG_MAX)
109143
count = 0;
110-
144+
111145
/*
112146
* switch into the portal context
113147
*/

‎src/backend/parser/gram.y

Lines changed: 5 additions & 16 deletions
Original file line numberDiff line numberDiff line change
@@ -11,7 +11,7 @@
1111
*
1212
*
1313
* IDENTIFICATION
14-
* $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.388 2002/12/12 20:35:13 tgl Exp $
14+
* $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.389 2002/12/30 15:31:47 momjian Exp $
1515
*
1616
* HISTORY
1717
* AUTHOR DATE MAJOR EVENT
@@ -2591,13 +2591,6 @@ comment_text:
25912591
FetchStmt: FETCH direction fetch_how_many from_in name
25922592
{
25932593
FetchStmt *n = makeNode(FetchStmt);
2594-
if ($2 == RELATIVE)
2595-
{
2596-
if ($3 == 0)
2597-
elog(ERROR,
2598-
"FETCH / RELATIVE at current position is not supported");
2599-
$2 = FORWARD;
2600-
}
26012594
if ($3 < 0)
26022595
{
26032596
$3 = -$3;
@@ -2629,10 +2622,6 @@ FetchStmt: FETCH direction fetch_how_many from_in name
26292622
| FETCH direction from_in name
26302623
{
26312624
FetchStmt *n = makeNode(FetchStmt);
2632-
if ($2 == RELATIVE)
2633-
{
2634-
$2 = FORWARD;
2635-
}
26362625
n->direction = $2;
26372626
n->howMany = 1;
26382627
n->portalname = $4;
@@ -2719,20 +2708,20 @@ FetchStmt: FETCH direction fetch_how_many from_in name
27192708

27202709
direction: FORWARD { $$ = FORWARD; }
27212710
| BACKWARD { $$ = BACKWARD; }
2722-
| RELATIVE { $$ = RELATIVE; }
2711+
| RELATIVE { $$ = FORWARD; }
27232712
| ABSOLUTE
27242713
{
27252714
elog(NOTICE,
27262715
"FETCH / ABSOLUTE not supported, using RELATIVE");
2727-
$$ = RELATIVE;
2716+
$$ = FORWARD;
27282717
}
27292718
;
27302719

27312720
fetch_how_many:
27322721
Iconst { $$ = $1; }
27332722
| '-' Iconst { $$ = - $2; }
2734-
| ALL { $$ = INT_MAX; }
2735-
| LAST { $$ = INT_MAX; }
2723+
| ALL { $$ = LONG_MAX; }
2724+
| LAST { $$ = LONG_MAX; }
27362725
| NEXT { $$ = 1; }
27372726
| PRIOR { $$ = -1; }
27382727
;

‎src/backend/tcop/utility.c

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -10,7 +10,7 @@
1010
*
1111
*
1212
* IDENTIFICATION
13-
* $Header: /cvsroot/pgsql/src/backend/tcop/utility.c,v 1.185 2002/12/06 05:00:31 momjian Exp $
13+
* $Header: /cvsroot/pgsql/src/backend/tcop/utility.c,v 1.186 2002/12/30 15:31:48 momjian Exp $
1414
*
1515
*-------------------------------------------------------------------------
1616
*/
@@ -257,7 +257,7 @@ ProcessUtility(Node *parsetree,
257257
FetchStmt *stmt = (FetchStmt *) parsetree;
258258
char *portalName = stmt->portalname;
259259
bool forward;
260-
int count;
260+
long count;
261261

262262
forward = (bool) (stmt->direction == FORWARD);
263263

‎src/include/commands/portalcmds.h

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@
77
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
88
* Portions Copyright (c) 1994, Regents of the University of California
99
*
10-
* $Id: portalcmds.h,v 1.3 2002/11/13 00:44:09 momjian Exp $
10+
* $Id: portalcmds.h,v 1.4 2002/12/30 15:31:50 momjian Exp $
1111
*
1212
*-------------------------------------------------------------------------
1313
*/
@@ -25,7 +25,7 @@
2525
* BadArg if forward invalid.
2626
* "ERROR" if portal not found.
2727
*/
28-
extern void PerformPortalFetch(char *name, bool forward, int count,
28+
extern void PerformPortalFetch(char *name, bool forward, long count,
2929
CommandDest dest, char *completionTag);
3030

3131
/*

‎src/include/nodes/parsenodes.h

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@
77
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
88
* Portions Copyright (c) 1994, Regents of the University of California
99
*
10-
* $Id: parsenodes.h,v 1.223 2002/12/12 20:35:16 tgl Exp $
10+
* $Id: parsenodes.h,v 1.224 2002/12/30 15:31:51 momjian Exp $
1111
*
1212
*-------------------------------------------------------------------------
1313
*/
@@ -1198,7 +1198,7 @@ typedef struct FetchStmt
11981198
{
11991199
NodeTag type;
12001200
int direction; /* FORWARD or BACKWARD */
1201-
int howMany; /* amount to fetch */
1201+
long howMany; /* amount to fetch */
12021202
char *portalname; /* name of portal (cursor) */
12031203
bool ismove; /* TRUE if MOVE */
12041204
} FetchStmt;

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