Allow MOVE FORWARD n, MOVE BACKWARD n, MOVE FORWARD ALL, MOVE BACKWARD ALL
in plpgsql. Clean up a couple of corner cases in the MOVE/FETCH syntax. Pavel Stehule
This commit is contained in:
Tom Lane
parent
25549edb26
commit
960d7ff022
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@ -1,4 +1,4 @@
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<!-- $PostgreSQL: pgsql/doc/src/sgml/plpgsql.sgml,v 1.142 2009/06/18 10:22:08 petere Exp $ -->
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<!-- $PostgreSQL: pgsql/doc/src/sgml/plpgsql.sgml,v 1.143 2009/09/29 20:05:29 tgl Exp $ -->
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<chapter id="plpgsql">
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<title><application>PL/pgSQL</application> - <acronym>SQL</acronym> Procedural Language</title>
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@ -2655,16 +2655,18 @@ MOVE <optional> <replaceable>direction</replaceable> { FROM | IN } </optional> <
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</para>
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<para>
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The options for the <replaceable>direction</replaceable> clause are
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the same as for <command>FETCH</>, namely
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The <replaceable>direction</replaceable> clause can be any of the
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variants allowed in the SQL <xref linkend="sql-fetch"
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endterm="sql-fetch-title"> command, namely
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<literal>NEXT</>,
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<literal>PRIOR</>,
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<literal>FIRST</>,
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<literal>LAST</>,
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<literal>ABSOLUTE</> <replaceable>count</replaceable>,
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<literal>RELATIVE</> <replaceable>count</replaceable>,
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<literal>FORWARD</>, or
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<literal>BACKWARD</>.
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<literal>ALL</>,
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<literal>FORWARD</> <optional> <replaceable>count</replaceable> | <literal>ALL</> </optional>, or
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<literal>BACKWARD</> <optional> <replaceable>count</replaceable> | <literal>ALL</> </optional>.
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Omitting <replaceable>direction</replaceable> is the same
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as specifying <literal>NEXT</>.
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<replaceable>direction</replaceable> values that require moving
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@ -2678,6 +2680,7 @@ MOVE <optional> <replaceable>direction</replaceable> { FROM | IN } </optional> <
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MOVE curs1;
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MOVE LAST FROM curs3;
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MOVE RELATIVE -2 FROM curs4;
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MOVE FORWARD 2 FROM curs4;
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</programlisting>
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</para>
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</sect3>
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@ -9,7 +9,7 @@
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*
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/pl/plpgsql/src/gram.y,v 1.127 2009/07/22 02:31:38 joe Exp $
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* $PostgreSQL: pgsql/src/pl/plpgsql/src/gram.y,v 1.128 2009/09/29 20:05:29 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -48,6 +48,8 @@ static PLpgSQL_expr *read_sql_stmt(const char *sqlstart);
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static PLpgSQL_type *read_datatype(int tok);
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static PLpgSQL_stmt *make_execsql_stmt(const char *sqlstart, int lineno);
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static PLpgSQL_stmt_fetch *read_fetch_direction(void);
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static void complete_direction(PLpgSQL_stmt_fetch *fetch,
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bool *check_FROM);
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static PLpgSQL_stmt *make_return_stmt(int lineno);
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static PLpgSQL_stmt *make_return_next_stmt(int lineno);
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static PLpgSQL_stmt *make_return_query_stmt(int lineno);
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@ -178,6 +180,7 @@ static List *read_raise_options(void);
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* Keyword tokens
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*/
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%token K_ALIAS
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%token K_ALL
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%token K_ASSIGN
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%token K_BEGIN
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%token K_BY
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@ -1622,6 +1625,15 @@ stmt_fetch : K_FETCH lno opt_fetch_direction cursor_variable K_INTO
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if (yylex() != ';')
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yyerror("syntax error");
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/*
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* We don't allow multiple rows in PL/pgSQL's FETCH
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* statement, only in MOVE.
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*/
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if (fetch->returns_multiple_rows)
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ereport(ERROR,
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(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
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errmsg("FETCH statement cannot return multiple rows")));
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fetch->lineno = $2;
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fetch->rec = rec;
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fetch->row = row;
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@ -2252,6 +2264,9 @@ make_execsql_stmt(const char *sqlstart, int lineno)
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}
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/*
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* Read FETCH or MOVE direction clause (everything through FROM/IN).
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*/
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static PLpgSQL_stmt_fetch *
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read_fetch_direction(void)
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{
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@ -2269,6 +2284,7 @@ read_fetch_direction(void)
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fetch->direction = FETCH_FORWARD;
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fetch->how_many = 1;
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fetch->expr = NULL;
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fetch->returns_multiple_rows = false;
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/*
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* Most of the direction keywords are not plpgsql keywords, so we
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@ -2311,26 +2327,46 @@ read_fetch_direction(void)
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NULL);
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check_FROM = false;
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}
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else if (pg_strcasecmp(yytext, "all") == 0)
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{
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fetch->how_many = FETCH_ALL;
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fetch->returns_multiple_rows = true;
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}
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else if (pg_strcasecmp(yytext, "forward") == 0)
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{
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/* use defaults */
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complete_direction(fetch, &check_FROM);
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}
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else if (pg_strcasecmp(yytext, "backward") == 0)
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{
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fetch->direction = FETCH_BACKWARD;
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complete_direction(fetch, &check_FROM);
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}
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else if (tok != T_SCALAR)
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else if (tok == K_FROM || tok == K_IN)
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{
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/* empty direction */
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check_FROM = false;
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}
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else if (tok == T_SCALAR)
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{
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/* Assume there's no direction clause and tok is a cursor name */
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plpgsql_push_back_token(tok);
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fetch->expr = read_sql_expression2(K_FROM, K_IN,
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"FROM or IN",
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NULL);
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check_FROM = false;
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}
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else
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{
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/* Assume there's no direction clause */
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/*
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* Assume it's a count expression with no preceding keyword.
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* Note: we allow this syntax because core SQL does, but we don't
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* document it because of the ambiguity with the omitted-direction
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* case. For instance, "MOVE n IN c" will fail if n is a scalar.
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* Perhaps this can be improved someday, but it's hardly worth a
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* lot of work.
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*/
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plpgsql_push_back_token(tok);
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fetch->expr = read_sql_expression2(K_FROM, K_IN,
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"FROM or IN",
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NULL);
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fetch->returns_multiple_rows = true;
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check_FROM = false;
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}
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@ -2345,6 +2381,43 @@ read_fetch_direction(void)
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return fetch;
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}
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/*
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* Process remainder of FETCH/MOVE direction after FORWARD or BACKWARD.
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* Allows these cases:
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* FORWARD expr, FORWARD ALL, FORWARD
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* BACKWARD expr, BACKWARD ALL, BACKWARD
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*/
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static void
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complete_direction(PLpgSQL_stmt_fetch *fetch, bool *check_FROM)
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{
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int tok;
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tok = yylex();
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if (tok == 0)
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yyerror("unexpected end of function definition");
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if (tok == K_FROM || tok == K_IN)
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{
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*check_FROM = false;
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return;
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}
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if (tok == K_ALL)
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{
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fetch->how_many = FETCH_ALL;
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fetch->returns_multiple_rows = true;
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*check_FROM = true;
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return;
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}
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plpgsql_push_back_token(tok);
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fetch->expr = read_sql_expression2(K_FROM, K_IN,
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"FROM or IN",
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NULL);
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fetch->returns_multiple_rows = true;
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*check_FROM = false;
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}
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static PLpgSQL_stmt *
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make_return_stmt(int lineno)
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@ -3043,11 +3116,11 @@ make_case(int lineno, PLpgSQL_expr *t_expr,
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/* copy expression query without SELECT keyword (expr->query + 7) */
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Assert(strncmp(expr->query, "SELECT ", 7) == 0);
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/* And do the string hacking */
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initStringInfo(&ds);
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appendStringInfo(&ds, "SELECT $%d IN(%s)",
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appendStringInfo(&ds, "SELECT $%d IN(%s)",
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nparams + 1,
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expr->query + 7);
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@ -8,7 +8,7 @@
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*
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_funcs.c,v 1.80 2009/07/22 02:31:38 joe Exp $
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* $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_funcs.c,v 1.81 2009/09/29 20:05:29 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -854,7 +854,7 @@ dump_cursor_direction(PLpgSQL_stmt_fetch *stmt)
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printf("\n");
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}
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else
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printf("%d\n", stmt->how_many);
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printf("%ld\n", stmt->how_many);
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dump_indent -= 2;
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}
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@ -8,7 +8,7 @@
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*
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/pl/plpgsql/src/plpgsql.h,v 1.116 2009/09/22 23:43:42 tgl Exp $
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* $PostgreSQL: pgsql/src/pl/plpgsql/src/plpgsql.h,v 1.117 2009/09/29 20:05:29 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -517,9 +517,10 @@ typedef struct
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PLpgSQL_row *row;
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int curvar; /* cursor variable to fetch from */
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FetchDirection direction; /* fetch direction */
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int how_many; /* count, if constant (expr is NULL) */
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long how_many; /* count, if constant (expr is NULL) */
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PLpgSQL_expr *expr; /* count, if expression */
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bool is_move; /* is this a fetch or move? */
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bool returns_multiple_rows; /* can return more than one row? */
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} PLpgSQL_stmt_fetch;
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@ -9,7 +9,7 @@
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*
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/pl/plpgsql/src/scan.l,v 1.71 2009/07/13 00:42:18 tgl Exp $
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* $PostgreSQL: pgsql/src/pl/plpgsql/src/scan.l,v 1.72 2009/09/29 20:05:29 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -147,6 +147,7 @@ param \${digit}+
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= { return K_ASSIGN; }
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\.\. { return K_DOTDOT; }
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alias { return K_ALIAS; }
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all { return K_ALL; }
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begin { return K_BEGIN; }
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by { return K_BY; }
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case { return K_CASE; }
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@ -3025,6 +3025,28 @@ select * from sc_test();
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0
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(3 rows)
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create or replace function sc_test() returns setof integer as $$
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declare
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c refcursor;
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x integer;
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begin
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open c scroll for execute 'select f1 from int4_tbl';
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fetch last from c into x;
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while found loop
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return next x;
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move backward 2 from c;
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fetch relative -1 from c into x;
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end loop;
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close c;
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end;
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$$ language plpgsql;
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select * from sc_test();
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sc_test
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-------------
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-2147483647
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123456
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(2 rows)
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create or replace function sc_test() returns setof integer as $$
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declare
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c cursor for select * from generate_series(1, 10);
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@ -3052,6 +3074,26 @@ select * from sc_test();
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9
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(3 rows)
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create or replace function sc_test() returns setof integer as $$
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declare
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c cursor for select * from generate_series(1, 10);
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x integer;
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begin
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open c;
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move forward all in c;
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fetch backward from c into x;
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if found then
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return next x;
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end if;
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close c;
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end;
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$$ language plpgsql;
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select * from sc_test();
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sc_test
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---------
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10
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(1 row)
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drop function sc_test();
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-- test qualified variable names
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create function pl_qual_names (param1 int) returns void as $$
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@ -3864,7 +3906,7 @@ drop function strtest();
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-- Test anonymous code blocks.
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DO $$
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DECLARE r record;
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BEGIN
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BEGIN
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FOR r IN SELECT rtrim(roomno) AS roomno, comment FROM Room ORDER BY roomno
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LOOP
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RAISE NOTICE '%, %', r.roomno, r.comment;
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@ -3887,7 +3929,7 @@ LINE 1: DO LANGUAGE plpgsql $$begin return 1; end$$;
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^
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DO LANGUAGE plpgsql $$
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DECLARE r record;
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BEGIN
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BEGIN
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FOR r IN SELECT rtrim(roomno) AS roomno, foo FROM Room ORDER BY roomno
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LOOP
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RAISE NOTICE '%, %', r.roomno, r.comment;
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@ -2511,6 +2511,24 @@ $$ language plpgsql;
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select * from sc_test();
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create or replace function sc_test() returns setof integer as $$
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declare
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c refcursor;
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x integer;
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begin
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open c scroll for execute 'select f1 from int4_tbl';
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fetch last from c into x;
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while found loop
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return next x;
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move backward 2 from c;
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fetch relative -1 from c into x;
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end loop;
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close c;
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end;
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$$ language plpgsql;
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select * from sc_test();
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create or replace function sc_test() returns setof integer as $$
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declare
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c cursor for select * from generate_series(1, 10);
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@ -2533,6 +2551,23 @@ $$ language plpgsql;
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select * from sc_test();
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create or replace function sc_test() returns setof integer as $$
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declare
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c cursor for select * from generate_series(1, 10);
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x integer;
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begin
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open c;
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move forward all in c;
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fetch backward from c into x;
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if found then
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return next x;
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end if;
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close c;
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end;
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$$ language plpgsql;
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select * from sc_test();
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drop function sc_test();
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-- test qualified variable names
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@ -3084,7 +3119,7 @@ drop function strtest();
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DO $$
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DECLARE r record;
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BEGIN
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BEGIN
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FOR r IN SELECT rtrim(roomno) AS roomno, comment FROM Room ORDER BY roomno
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LOOP
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RAISE NOTICE '%, %', r.roomno, r.comment;
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@ -3096,7 +3131,7 @@ DO LANGUAGE plpgsql $$begin return 1; end$$;
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DO LANGUAGE plpgsql $$
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DECLARE r record;
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BEGIN
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BEGIN
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FOR r IN SELECT rtrim(roomno) AS roomno, foo FROM Room ORDER BY roomno
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LOOP
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RAISE NOTICE '%, %', r.roomno, r.comment;
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