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Allow MOVE FORWARD n, MOVE BACKWARD n, MOVE FORWARD ALL, MOVE BACKWARD ALL

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in plpgsql.  Clean up a couple of corner cases in the MOVE/FETCH syntax.

Pavel Stehule
REL8_5_ALPHA2_BRANCH
Tom Lane 16 years ago
parent 25549edb26
commit 960d7ff022
7 changed files with 178 additions and 23 deletions
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
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  1. 13
      doc/src/sgml/plpgsql.sgml
  2. 91
      src/pl/plpgsql/src/gram.y
  3. 4
      src/pl/plpgsql/src/pl_funcs.c
  4. 5
      src/pl/plpgsql/src/plpgsql.h
  5. 3
      src/pl/plpgsql/src/scan.l
  6. 46
      src/test/regress/expected/plpgsql.out
  7. 39
      src/test/regress/sql/plpgsql.sql

13
doc/src/sgml/plpgsql.sgml
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@ -1,4 +1,4 @@
<!-- $PostgreSQL: pgsql/doc/src/sgml/plpgsql.sgml,v 1.142 2009/06/18 10:22:08 petere Exp $ -->
<!-- $PostgreSQL: pgsql/doc/src/sgml/plpgsql.sgml,v 1.143 2009/09/29 20:05:29 tgl Exp $ -->
<chapter id="plpgsql">
<title><application>PL/pgSQL</application> - <acronym>SQL</acronym> Procedural Language</title>
@ -2655,16 +2655,18 @@ MOVE <optional> <replaceable>direction</replaceable> { FROM | IN } </optional> <
</para>
<para>
The options for the <replaceable>direction</replaceable> clause are
the same as for <command>FETCH</>, namely
The <replaceable>direction</replaceable> clause can be any of the
variants allowed in the SQL <xref linkend="sql-fetch"
endterm="sql-fetch-title"> command, namely
<literal>NEXT</>,
<literal>PRIOR</>,
<literal>FIRST</>,
<literal>LAST</>,
<literal>ABSOLUTE</> <replaceable>count</replaceable>,
<literal>RELATIVE</> <replaceable>count</replaceable>,
<literal>FORWARD</>, or
<literal>BACKWARD</>.
<literal>ALL</>,
<literal>FORWARD</> <optional> <replaceable>count</replaceable> | <literal>ALL</> </optional>, or
<literal>BACKWARD</> <optional> <replaceable>count</replaceable> | <literal>ALL</> </optional>.
Omitting <replaceable>direction</replaceable> is the same
as specifying <literal>NEXT</>.
<replaceable>direction</replaceable> values that require moving
@ -2678,6 +2680,7 @@ MOVE <optional> <replaceable>direction</replaceable> { FROM | IN } </optional> <
MOVE curs1;
MOVE LAST FROM curs3;
MOVE RELATIVE -2 FROM curs4;
MOVE FORWARD 2 FROM curs4;
</programlisting>
</para>
</sect3>

91
src/pl/plpgsql/src/gram.y
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@ -9,7 +9,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/pl/plpgsql/src/gram.y,v 1.127 2009/07/22 02:31:38 joe Exp $
* $PostgreSQL: pgsql/src/pl/plpgsql/src/gram.y,v 1.128 2009/09/29 20:05:29 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -48,6 +48,8 @@ static PLpgSQL_expr *read_sql_stmt(const char *sqlstart);
static PLpgSQL_type *read_datatype(int tok);
static PLpgSQL_stmt *make_execsql_stmt(const char *sqlstart, int lineno);
static PLpgSQL_stmt_fetch *read_fetch_direction(void);
static void complete_direction(PLpgSQL_stmt_fetch *fetch,
bool *check_FROM);
static PLpgSQL_stmt *make_return_stmt(int lineno);
static PLpgSQL_stmt *make_return_next_stmt(int lineno);
static PLpgSQL_stmt *make_return_query_stmt(int lineno);
@ -178,6 +180,7 @@ static List *read_raise_options(void);
* Keyword tokens
*/
%token K_ALIAS
%token K_ALL
%token K_ASSIGN
%token K_BEGIN
%token K_BY
@ -1622,6 +1625,15 @@ stmt_fetch : K_FETCH lno opt_fetch_direction cursor_variable K_INTO
if (yylex() != ';')
yyerror("syntax error");
/*
* We don't allow multiple rows in PL/pgSQL's FETCH
* statement, only in MOVE.
*/
if (fetch->returns_multiple_rows)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("FETCH statement cannot return multiple rows")));
fetch->lineno = $2;
fetch->rec = rec;
fetch->row = row;
@ -2252,6 +2264,9 @@ make_execsql_stmt(const char *sqlstart, int lineno)
}
/*
* Read FETCH or MOVE direction clause (everything through FROM/IN).
*/
static PLpgSQL_stmt_fetch *
read_fetch_direction(void)
{
@ -2269,6 +2284,7 @@ read_fetch_direction(void)
fetch->direction = FETCH_FORWARD;
fetch->how_many = 1;
fetch->expr = NULL;
fetch->returns_multiple_rows = false;
/*
* Most of the direction keywords are not plpgsql keywords, so we
@ -2311,26 +2327,46 @@ read_fetch_direction(void)
NULL);
check_FROM = false;
}
else if (pg_strcasecmp(yytext, "all") == 0)
{
fetch->how_many = FETCH_ALL;
fetch->returns_multiple_rows = true;
}
else if (pg_strcasecmp(yytext, "forward") == 0)
{
/* use defaults */
complete_direction(fetch, &check_FROM);
}
else if (pg_strcasecmp(yytext, "backward") == 0)
{
fetch->direction = FETCH_BACKWARD;
complete_direction(fetch, &check_FROM);
}
else if (tok != T_SCALAR)
else if (tok == K_FROM || tok == K_IN)
{
/* empty direction */
check_FROM = false;
}
else if (tok == T_SCALAR)
{
/* Assume there's no direction clause and tok is a cursor name */
plpgsql_push_back_token(tok);
fetch->expr = read_sql_expression2(K_FROM, K_IN,
"FROM or IN",
NULL);
check_FROM = false;
}
else
{
/* Assume there's no direction clause */
/*
* Assume it's a count expression with no preceding keyword.
* Note: we allow this syntax because core SQL does, but we don't
* document it because of the ambiguity with the omitted-direction
* case. For instance, "MOVE n IN c" will fail if n is a scalar.
* Perhaps this can be improved someday, but it's hardly worth a
* lot of work.
*/
plpgsql_push_back_token(tok);
fetch->expr = read_sql_expression2(K_FROM, K_IN,
"FROM or IN",
NULL);
fetch->returns_multiple_rows = true;
check_FROM = false;
}
@ -2345,6 +2381,43 @@ read_fetch_direction(void)
return fetch;
}
/*
* Process remainder of FETCH/MOVE direction after FORWARD or BACKWARD.
* Allows these cases:
* FORWARD expr, FORWARD ALL, FORWARD
* BACKWARD expr, BACKWARD ALL, BACKWARD
*/
static void
complete_direction(PLpgSQL_stmt_fetch *fetch, bool *check_FROM)
{
int tok;
tok = yylex();
if (tok == 0)
yyerror("unexpected end of function definition");
if (tok == K_FROM || tok == K_IN)
{
*check_FROM = false;
return;
}
if (tok == K_ALL)
{
fetch->how_many = FETCH_ALL;
fetch->returns_multiple_rows = true;
*check_FROM = true;
return;
}
plpgsql_push_back_token(tok);
fetch->expr = read_sql_expression2(K_FROM, K_IN,
"FROM or IN",
NULL);
fetch->returns_multiple_rows = true;
*check_FROM = false;
}
static PLpgSQL_stmt *
make_return_stmt(int lineno)
@ -3043,11 +3116,11 @@ make_case(int lineno, PLpgSQL_expr *t_expr,
/* copy expression query without SELECT keyword (expr->query + 7) */
Assert(strncmp(expr->query, "SELECT ", 7) == 0);
/* And do the string hacking */
initStringInfo(&ds);
appendStringInfo(&ds, "SELECT $%d IN(%s)",
appendStringInfo(&ds, "SELECT $%d IN(%s)",
nparams + 1,
expr->query + 7);

4
src/pl/plpgsql/src/pl_funcs.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_funcs.c,v 1.80 2009/07/22 02:31:38 joe Exp $
* $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_funcs.c,v 1.81 2009/09/29 20:05:29 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -854,7 +854,7 @@ dump_cursor_direction(PLpgSQL_stmt_fetch *stmt)
printf("\n");
}
else
printf("%d\n", stmt->how_many);
printf("%ld\n", stmt->how_many);
dump_indent -= 2;
}

5
src/pl/plpgsql/src/plpgsql.h
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/pl/plpgsql/src/plpgsql.h,v 1.116 2009/09/22 23:43:42 tgl Exp $
* $PostgreSQL: pgsql/src/pl/plpgsql/src/plpgsql.h,v 1.117 2009/09/29 20:05:29 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -517,9 +517,10 @@ typedef struct
PLpgSQL_row *row;
int curvar; /* cursor variable to fetch from */
FetchDirection direction; /* fetch direction */
int how_many; /* count, if constant (expr is NULL) */
long how_many; /* count, if constant (expr is NULL) */
PLpgSQL_expr *expr; /* count, if expression */
bool is_move; /* is this a fetch or move? */
bool returns_multiple_rows; /* can return more than one row? */
} PLpgSQL_stmt_fetch;

3
src/pl/plpgsql/src/scan.l
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@ -9,7 +9,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/pl/plpgsql/src/scan.l,v 1.71 2009/07/13 00:42:18 tgl Exp $
* $PostgreSQL: pgsql/src/pl/plpgsql/src/scan.l,v 1.72 2009/09/29 20:05:29 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -147,6 +147,7 @@ param \${digit}+
= { return K_ASSIGN; }
\.\. { return K_DOTDOT; }
alias { return K_ALIAS; }
all { return K_ALL; }
begin { return K_BEGIN; }
by { return K_BY; }
case { return K_CASE; }

46
src/test/regress/expected/plpgsql.out
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@ -3025,6 +3025,28 @@ select * from sc_test();
0
(3 rows)
create or replace function sc_test() returns setof integer as $$
declare
c refcursor;
x integer;
begin
open c scroll for execute 'select f1 from int4_tbl';
fetch last from c into x;
while found loop
return next x;
move backward 2 from c;
fetch relative -1 from c into x;
end loop;
close c;
end;
$$ language plpgsql;
select * from sc_test();
sc_test
-------------
-2147483647
123456
(2 rows)
create or replace function sc_test() returns setof integer as $$
declare
c cursor for select * from generate_series(1, 10);
@ -3052,6 +3074,26 @@ select * from sc_test();
9
(3 rows)
create or replace function sc_test() returns setof integer as $$
declare
c cursor for select * from generate_series(1, 10);
x integer;
begin
open c;
move forward all in c;
fetch backward from c into x;
if found then
return next x;
end if;
close c;
end;
$$ language plpgsql;
select * from sc_test();
sc_test
---------
10
(1 row)
drop function sc_test();
-- test qualified variable names
create function pl_qual_names (param1 int) returns void as $$
@ -3864,7 +3906,7 @@ drop function strtest();
-- Test anonymous code blocks.
DO $$
DECLARE r record;
BEGIN
BEGIN
FOR r IN SELECT rtrim(roomno) AS roomno, comment FROM Room ORDER BY roomno
LOOP
RAISE NOTICE '%, %', r.roomno, r.comment;
@ -3887,7 +3929,7 @@ LINE 1: DO LANGUAGE plpgsql $$begin return 1; end$$;
^
DO LANGUAGE plpgsql $$
DECLARE r record;
BEGIN
BEGIN
FOR r IN SELECT rtrim(roomno) AS roomno, foo FROM Room ORDER BY roomno
LOOP
RAISE NOTICE '%, %', r.roomno, r.comment;

39
src/test/regress/sql/plpgsql.sql
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@ -2511,6 +2511,24 @@ $$ language plpgsql;
select * from sc_test();
create or replace function sc_test() returns setof integer as $$
declare
c refcursor;
x integer;
begin
open c scroll for execute 'select f1 from int4_tbl';
fetch last from c into x;
while found loop
return next x;
move backward 2 from c;
fetch relative -1 from c into x;
end loop;
close c;
end;
$$ language plpgsql;
select * from sc_test();
create or replace function sc_test() returns setof integer as $$
declare
c cursor for select * from generate_series(1, 10);
@ -2533,6 +2551,23 @@ $$ language plpgsql;
select * from sc_test();
create or replace function sc_test() returns setof integer as $$
declare
c cursor for select * from generate_series(1, 10);
x integer;
begin
open c;
move forward all in c;
fetch backward from c into x;
if found then
return next x;
end if;
close c;
end;
$$ language plpgsql;
select * from sc_test();
drop function sc_test();
-- test qualified variable names
@ -3084,7 +3119,7 @@ drop function strtest();
DO $$
DECLARE r record;
BEGIN
BEGIN
FOR r IN SELECT rtrim(roomno) AS roomno, comment FROM Room ORDER BY roomno
LOOP
RAISE NOTICE '%, %', r.roomno, r.comment;
@ -3096,7 +3131,7 @@ DO LANGUAGE plpgsql $$begin return 1; end$$;
DO LANGUAGE plpgsql $$
DECLARE r record;
BEGIN
BEGIN
FOR r IN SELECT rtrim(roomno) AS roomno, foo FROM Room ORDER BY roomno
LOOP
RAISE NOTICE '%, %', r.roomno, r.comment;

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