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Add support for passing cursor parameters in named notation in PL/pgSQL.

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Yeb Havinga, reviewed by Kevin Grittner, with small changes by me.
This commit is contained in:
Heikki Linnakangas 2011-12-14 15:55:37 +02:00
parent 2dd9322ba6
commit 4adead1d22
6 changed files with 429 additions and 17 deletions
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23
doc/src/sgml/plpgsql.sgml
View File

@ -2823,11 +2823,11 @@ OPEN curs1 FOR EXECUTE 'SELECT * FROM ' || quote_ident(tabname)
</para>
</sect3>
<sect3>
<sect3 id="plpgsql-open-bound-cursor">
<title>Opening a Bound Cursor</title>
<synopsis>
OPEN <replaceable>bound_cursorvar</replaceable> <optional> ( <replaceable>argument_values</replaceable> ) </optional>;
OPEN <replaceable>bound_cursorvar</replaceable> <optional> ( <optional> <replaceable>argument_name</replaceable> := </optional> <replaceable>argument_value</replaceable> <optional>, ...</optional> ) </optional>;
</synopsis>
<para>
@ -2846,11 +2846,22 @@ OPEN <replaceable>bound_cursorvar</replaceable> <optional> ( <replaceable>argume
behavior was already determined.
</para>
<para>
Argument values can be passed using either <firstterm>positional</firstterm>
or <firstterm>named</firstterm> notation. In positional
notation, all arguments are specified in order. In named notation,
each argument's name is specified using <literal>:=</literal> to
separate it from the argument expression. Similar to calling
functions, described in <xref linkend="sql-syntax-calling-funcs">, it
is also allowed to mix positional and named notation.
</para>
<para>
Examples (these use the cursor declaration examples above):
<programlisting>
OPEN curs2;
OPEN curs3(42);
OPEN curs3(key := 42);
</programlisting>
</para>
@ -3169,7 +3180,7 @@ COMMIT;
<synopsis>
<optional> &lt;&lt;<replaceable>label</replaceable>&gt;&gt; </optional>
FOR <replaceable>recordvar</replaceable> IN <replaceable>bound_cursorvar</replaceable> <optional> ( <replaceable>argument_values</replaceable> ) </optional> LOOP
FOR <replaceable>recordvar</replaceable> IN <replaceable>bound_cursorvar</replaceable> <optional> ( <optional> <replaceable>argument_name</replaceable> := </optional> <replaceable>argument_value</replaceable> <optional>, ...</optional> ) </optional> LOOP
<replaceable>statements</replaceable>
END LOOP <optional> <replaceable>label</replaceable> </optional>;
</synopsis>
@ -3180,7 +3191,11 @@ END LOOP <optional> <replaceable>label</replaceable> </optional>;
the cursor again when the loop exits. A list of actual argument value
expressions must appear if and only if the cursor was declared to take
arguments. These values will be substituted in the query, in just
the same way as during an <command>OPEN</>.
the same way as during an <command>OPEN</> (see <xref
linkend="plpgsql-open-bound-cursor">).
</para>
<para>
The variable <replaceable>recordvar</replaceable> is automatically
defined as type <type>record</> and exists only inside the loop (any
existing definition of the variable name is ignored within the loop).

154
src/pl/plpgsql/src/gram.y
View File

@ -67,6 +67,7 @@ static PLpgSQL_expr *read_sql_construct(int until,
const char *sqlstart,
bool isexpression,
bool valid_sql,
bool trim,
int *startloc,
int *endtoken);
static PLpgSQL_expr *read_sql_expression(int until,
@ -1313,6 +1314,7 @@ for_control : for_variable K_IN
"SELECT ",
true,
false,
true,
&expr1loc,
&tok);
@ -1692,7 +1694,7 @@ stmt_raise : K_RAISE
expr = read_sql_construct(',', ';', K_USING,
", or ; or USING",
"SELECT ",
true, true,
true, true, true,
NULL, &tok);
new->params = lappend(new->params, expr);
}
@ -1790,7 +1792,7 @@ stmt_dynexecute : K_EXECUTE
expr = read_sql_construct(K_INTO, K_USING, ';',
"INTO or USING or ;",
"SELECT ",
true, true,
true, true, true,
NULL, &endtoken);
new = palloc(sizeof(PLpgSQL_stmt_dynexecute));
@ -1829,7 +1831,7 @@ stmt_dynexecute : K_EXECUTE
expr = read_sql_construct(',', ';', K_INTO,
", or ; or INTO",
"SELECT ",
true, true,
true, true, true,
NULL, &endtoken);
new->params = lappend(new->params, expr);
} while (endtoken == ',');
@ -2322,7 +2324,7 @@ static PLpgSQL_expr *
read_sql_expression(int until, const char *expected)
{
return read_sql_construct(until, 0, 0, expected,
"SELECT ", true, true, NULL, NULL);
"SELECT ", true, true, true, NULL, NULL);
}
/* Convenience routine to read an expression with two possible terminators */
@ -2331,7 +2333,7 @@ read_sql_expression2(int until, int until2, const char *expected,
int *endtoken)
{
return read_sql_construct(until, until2, 0, expected,
"SELECT ", true, true, NULL, endtoken);
"SELECT ", true, true, true, NULL, endtoken);
}
/* Convenience routine to read a SQL statement that must end with ';' */
@ -2339,7 +2341,7 @@ static PLpgSQL_expr *
read_sql_stmt(const char *sqlstart)
{
return read_sql_construct(';', 0, 0, ";",
sqlstart, false, true, NULL, NULL);
sqlstart, false, true, true, NULL, NULL);
}
/*
@ -2352,6 +2354,7 @@ read_sql_stmt(const char *sqlstart)
* sqlstart: text to prefix to the accumulated SQL text
* isexpression: whether to say we're reading an "expression" or a "statement"
* valid_sql: whether to check the syntax of the expr (prefixed with sqlstart)
* trim: trim trailing whitespace
* startloc: if not NULL, location of first token is stored at *startloc
* endtoken: if not NULL, ending token is stored at *endtoken
* (this is only interesting if until2 or until3 isn't zero)
@ -2364,6 +2367,7 @@ read_sql_construct(int until,
const char *sqlstart,
bool isexpression,
bool valid_sql,
bool trim,
int *startloc,
int *endtoken)
{
@ -2443,8 +2447,11 @@ read_sql_construct(int until,
plpgsql_append_source_text(&ds, startlocation, yylloc);
/* trim any trailing whitespace, for neatness */
while (ds.len > 0 && scanner_isspace(ds.data[ds.len - 1]))
ds.data[--ds.len] = '\0';
if (trim)
{
while (ds.len > 0 && scanner_isspace(ds.data[ds.len - 1]))
ds.data[--ds.len] = '\0';
}
expr = palloc0(sizeof(PLpgSQL_expr));
expr->dtype = PLPGSQL_DTYPE_EXPR;
@ -3375,15 +3382,23 @@ check_labels(const char *start_label, const char *end_label, int end_location)
* Read the arguments (if any) for a cursor, followed by the until token
*
* If cursor has no args, just swallow the until token and return NULL.
* If it does have args, we expect to see "( expr [, expr ...] )" followed
* by the until token. Consume all that and return a SELECT query that
* evaluates the expression(s) (without the outer parens).
* If it does have args, we expect to see "( arg [, arg ...] )" followed
* by the until token, where arg may be a plain expression, or a named
* parameter assignment of the form argname := expr. Consume all that and
* return a SELECT query that evaluates the expression(s) (without the outer
* parens).
*/
static PLpgSQL_expr *
read_cursor_args(PLpgSQL_var *cursor, int until, const char *expected)
{
PLpgSQL_expr *expr;
PLpgSQL_row *row;
int tok;
int argc = 0;
char **argv;
StringInfoData ds;
char *sqlstart = "SELECT ";
bool named = false;
tok = yylex();
if (cursor->cursor_explicit_argrow < 0)
@ -3402,6 +3417,9 @@ read_cursor_args(PLpgSQL_var *cursor, int until, const char *expected)
return NULL;
}
row = (PLpgSQL_row *) plpgsql_Datums[cursor->cursor_explicit_argrow];
argv = (char **) palloc0(row->nfields * sizeof(char *));
/* Else better provide arguments */
if (tok != '(')
ereport(ERROR,
@ -3411,9 +3429,119 @@ read_cursor_args(PLpgSQL_var *cursor, int until, const char *expected)
parser_errposition(yylloc)));
/*
* Read expressions until the matching ')'.
* Read the arguments, one by one.
*/
expr = read_sql_expression(')', ")");
for (argc = 0; argc < row->nfields; argc++)
{
PLpgSQL_expr *item;
int endtoken;
int argpos;
int tok1,
tok2;
int arglocation;
/* Check if it's a named parameter: "param := value" */
plpgsql_peek2(&tok1, &tok2, &arglocation, NULL);
if (tok1 == IDENT && tok2 == COLON_EQUALS)
{
char *argname;
/* Read the argument name, and find its position */
yylex();
argname = yylval.str;
for (argpos = 0; argpos < row->nfields; argpos++)
{
if (strcmp(row->fieldnames[argpos], argname) == 0)
break;
}
if (argpos == row->nfields)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("cursor \"%s\" has no argument named \"%s\"",
cursor->refname, argname),
parser_errposition(yylloc)));
/*
* Eat the ":=". We already peeked, so the error should never
* happen.
*/
tok2 = yylex();
if (tok2 != COLON_EQUALS)
yyerror("syntax error");
named = true;
}
else
argpos = argc;
/*
* Read the value expression. To provide the user with meaningful
* parse error positions, we check the syntax immediately, instead of
* checking the final expression that may have the arguments
* reordered. Trailing whitespace must not be trimmed, because
* otherwise input of the form (param -- comment\n, param) would be
* translated into a form where the second parameter is commented
* out.
*/
item = read_sql_construct(',', ')', 0,
",\" or \")",
sqlstart,
true, true,
false, /* do not trim */
NULL, &endtoken);
if (endtoken == ')' && !(argc == row->nfields - 1))
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("not enough arguments for cursor \"%s\"",
cursor->refname),
parser_errposition(yylloc)));
if (endtoken == ',' && (argc == row->nfields - 1))
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("too many arguments for cursor \"%s\"",
cursor->refname),
parser_errposition(yylloc)));
if (argv[argpos] != NULL)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("duplicate value for cursor \"%s\" parameter \"%s\"",
cursor->refname, row->fieldnames[argpos]),
parser_errposition(arglocation)));
argv[argpos] = item->query + strlen(sqlstart);
}
/* Make positional argument list */
initStringInfo(&ds);
appendStringInfoString(&ds, sqlstart);
for (argc = 0; argc < row->nfields; argc++)
{
Assert(argv[argc] != NULL);
/*
* Because named notation allows permutated argument lists, include
* the parameter name for meaningful runtime errors.
*/
appendStringInfoString(&ds, argv[argc]);
if (named)
appendStringInfo(&ds, " AS %s",
quote_identifier(row->fieldnames[argc]));
if (argc < row->nfields - 1)
appendStringInfoString(&ds, ", ");
}
appendStringInfoChar(&ds, ';');
expr = palloc0(sizeof(PLpgSQL_expr));
expr->dtype = PLPGSQL_DTYPE_EXPR;
expr->query = pstrdup(ds.data);
expr->plan = NULL;
expr->paramnos = NULL;
expr->ns = plpgsql_ns_top();
pfree(ds.data);
/* Next we'd better find the until token */
tok = yylex();

30
src/pl/plpgsql/src/pl_scanner.c
View File

@ -423,6 +423,36 @@ plpgsql_append_source_text(StringInfo buf,
endlocation - startlocation);
}
/*
* Peek two tokens ahead in the input stream. The first token and its
* location the query are returned in *tok1_p and *tok1_loc, second token
* and its location in *tok2_p and *tok2_loc.
*
* NB: no variable or unreserved keyword lookup is performed here, they will
* be returned as IDENT. Reserved keywords are resolved as usual.
*/
void
plpgsql_peek2(int *tok1_p, int *tok2_p, int *tok1_loc, int *tok2_loc)
{
int tok1,
tok2;
TokenAuxData aux1,
aux2;
tok1 = internal_yylex(&aux1);
tok2 = internal_yylex(&aux2);
*tok1_p = tok1;
if (tok1_loc)
*tok1_loc = aux1.lloc;
*tok2_p = tok2;
if (tok2_loc)
*tok2_loc = aux2.lloc;
push_back_token(tok2, &aux2);
push_back_token(tok1, &aux1);
}
/*
* plpgsql_scanner_errposition
* Report an error cursor position, if possible.

2
src/pl/plpgsql/src/plpgsql.h
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@ -962,6 +962,8 @@ extern int plpgsql_yylex(void);
extern void plpgsql_push_back_token(int token);
extern void plpgsql_append_source_text(StringInfo buf,
int startlocation, int endlocation);
extern void plpgsql_peek2(int *tok1_p, int *tok2_p, int *tok1_loc,
int *tok2_loc);
extern int plpgsql_scanner_errposition(int location);
extern void plpgsql_yyerror(const char *message);
extern int plpgsql_location_to_lineno(int location);

129
src/test/regress/expected/plpgsql.out
View File

@ -2291,6 +2291,135 @@ select refcursor_test2(20000, 20000) as "Should be false",
f | t
(1 row)
--
-- tests for cursors with named parameter arguments
--
create function namedparmcursor_test1(int, int) returns boolean as $$
declare
c1 cursor (param1 int, param12 int) for select * from rc_test where a > param1 and b > param12;
nonsense record;
begin
open c1(param12 := $2, param1 := $1);
fetch c1 into nonsense;
close c1;
if found then
return true;
else
return false;
end if;
end
$$ language plpgsql;
select namedparmcursor_test1(20000, 20000) as "Should be false",
namedparmcursor_test1(20, 20) as "Should be true";
Should be false | Should be true
-----------------+----------------
f | t
(1 row)
-- mixing named and positional argument notations
create function namedparmcursor_test2(int, int) returns boolean as $$
declare
c1 cursor (param1 int, param2 int) for select * from rc_test where a > param1 and b > param2;
nonsense record;
begin
open c1(param1 := $1, $2);
fetch c1 into nonsense;
close c1;
if found then
return true;
else
return false;
end if;
end
$$ language plpgsql;
select namedparmcursor_test2(20, 20);
namedparmcursor_test2
-----------------------
t
(1 row)
-- mixing named and positional: param2 is given twice, once in named notation
-- and second time in positional notation. Should throw an error at parse time
create function namedparmcursor_test3() returns void as $$
declare
c1 cursor (param1 int, param2 int) for select * from rc_test where a > param1 and b > param2;
begin
open c1(param2 := 20, 21);
end
$$ language plpgsql;
ERROR: duplicate value for cursor "c1" parameter "param2"
LINE 5: open c1(param2 := 20, 21);
^
-- mixing named and positional: same as previous test, but param1 is duplicated
create function namedparmcursor_test4() returns void as $$
declare
c1 cursor (param1 int, param2 int) for select * from rc_test where a > param1 and b > param2;
begin
open c1(20, param1 := 21);
end
$$ language plpgsql;
ERROR: duplicate value for cursor "c1" parameter "param1"
LINE 5: open c1(20, param1 := 21);
^
-- duplicate named parameter, should throw an error at parse time
create function namedparmcursor_test5() returns void as $$
declare
c1 cursor (p1 int, p2 int) for
select * from tenk1 where thousand = p1 and tenthous = p2;
begin
open c1 (p2 := 77, p2 := 42);
end
$$ language plpgsql;
ERROR: duplicate value for cursor "c1" parameter "p2"
LINE 6: open c1 (p2 := 77, p2 := 42);
^
-- not enough parameters, should throw an error at parse time
create function namedparmcursor_test6() returns void as $$
declare
c1 cursor (p1 int, p2 int) for
select * from tenk1 where thousand = p1 and tenthous = p2;
begin
open c1 (p2 := 77);
end
$$ language plpgsql;
ERROR: not enough arguments for cursor "c1"
LINE 6: open c1 (p2 := 77);
^
-- division by zero runtime error, the context given in the error message
-- should be sensible
create function namedparmcursor_test7() returns void as $$
declare
c1 cursor (p1 int, p2 int) for
select * from tenk1 where thousand = p1 and tenthous = p2;
begin
open c1 (p2 := 77, p1 := 42/0);
end $$ language plpgsql;
select namedparmcursor_test7();
ERROR: division by zero
CONTEXT: SQL statement "SELECT 42/0 AS p1, 77 AS p2;"
PL/pgSQL function "namedparmcursor_test7" line 6 at OPEN
-- check that line comments work correctly within the argument list (there
-- is some special handling of this case in the code: the newline after the
-- comment must be preserved when the argument-evaluating query is
-- constructed, otherwise the comment effectively comments out the next
-- argument, too)
create function namedparmcursor_test8() returns int4 as $$
declare
c1 cursor (p1 int, p2 int) for
select count(*) from tenk1 where thousand = p1 and tenthous = p2;
n int4;
begin
open c1 (77 -- test
, 42);
fetch c1 into n;
return n;
end $$ language plpgsql;
select namedparmcursor_test8();
namedparmcursor_test8
-----------------------
0
(1 row)
--
-- tests for "raise" processing
--

108
src/test/regress/sql/plpgsql.sql
View File

@ -1945,6 +1945,114 @@ $$ language plpgsql;
select refcursor_test2(20000, 20000) as "Should be false",
refcursor_test2(20, 20) as "Should be true";
--
-- tests for cursors with named parameter arguments
--
create function namedparmcursor_test1(int, int) returns boolean as $$
declare
c1 cursor (param1 int, param12 int) for select * from rc_test where a > param1 and b > param12;
nonsense record;
begin
open c1(param12 := $2, param1 := $1);
fetch c1 into nonsense;
close c1;
if found then
return true;
else
return false;
end if;
end
$$ language plpgsql;
select namedparmcursor_test1(20000, 20000) as "Should be false",
namedparmcursor_test1(20, 20) as "Should be true";
-- mixing named and positional argument notations
create function namedparmcursor_test2(int, int) returns boolean as $$
declare
c1 cursor (param1 int, param2 int) for select * from rc_test where a > param1 and b > param2;
nonsense record;
begin
open c1(param1 := $1, $2);
fetch c1 into nonsense;
close c1;
if found then
return true;
else
return false;
end if;
end
$$ language plpgsql;
select namedparmcursor_test2(20, 20);
-- mixing named and positional: param2 is given twice, once in named notation
-- and second time in positional notation. Should throw an error at parse time
create function namedparmcursor_test3() returns void as $$
declare
c1 cursor (param1 int, param2 int) for select * from rc_test where a > param1 and b > param2;
begin
open c1(param2 := 20, 21);
end
$$ language plpgsql;
-- mixing named and positional: same as previous test, but param1 is duplicated
create function namedparmcursor_test4() returns void as $$
declare
c1 cursor (param1 int, param2 int) for select * from rc_test where a > param1 and b > param2;
begin
open c1(20, param1 := 21);
end
$$ language plpgsql;
-- duplicate named parameter, should throw an error at parse time
create function namedparmcursor_test5() returns void as $$
declare
c1 cursor (p1 int, p2 int) for
select * from tenk1 where thousand = p1 and tenthous = p2;
begin
open c1 (p2 := 77, p2 := 42);
end
$$ language plpgsql;
-- not enough parameters, should throw an error at parse time
create function namedparmcursor_test6() returns void as $$
declare
c1 cursor (p1 int, p2 int) for
select * from tenk1 where thousand = p1 and tenthous = p2;
begin
open c1 (p2 := 77);
end
$$ language plpgsql;
-- division by zero runtime error, the context given in the error message
-- should be sensible
create function namedparmcursor_test7() returns void as $$
declare
c1 cursor (p1 int, p2 int) for
select * from tenk1 where thousand = p1 and tenthous = p2;
begin
open c1 (p2 := 77, p1 := 42/0);
end $$ language plpgsql;
select namedparmcursor_test7();
-- check that line comments work correctly within the argument list (there
-- is some special handling of this case in the code: the newline after the
-- comment must be preserved when the argument-evaluating query is
-- constructed, otherwise the comment effectively comments out the next
-- argument, too)
create function namedparmcursor_test8() returns int4 as $$
declare
c1 cursor (p1 int, p2 int) for
select count(*) from tenk1 where thousand = p1 and tenthous = p2;
n int4;
begin
open c1 (77 -- test
, 42);
fetch c1 into n;
return n;
end $$ language plpgsql;
select namedparmcursor_test8();
--
-- tests for "raise" processing
--