<para>
The general syntax of a variable declaration is:
<synopsis>
-<replaceable>name</replaceable> <optional> CONSTANT </optional> <replaceable>type</replaceable> <optional> NOT NULL </optional> <optional> { DEFAULT | := } <replaceable>expression</replaceable> </optional>;
+<replaceable>name</replaceable> <optional> CONSTANT </optional> <replaceable>type</replaceable> <optional> COLLATE <replaceable>collation_name</replaceable> </optional> <optional> NOT NULL </optional> <optional> { DEFAULT | := } <replaceable>expression</replaceable> </optional>;
</synopsis>
The <literal>DEFAULT</> clause, if given, specifies the initial value assigned
to the variable when the block is entered. If the <literal>DEFAULT</> clause
is not given then the variable is initialized to the
<acronym>SQL</acronym> null value.
The <literal>CONSTANT</> option prevents the variable from being
- assigned to, so that its value will remain constant for the duration of
- the block.
+ assigned to after initialization, so that its value will remain constant
+ for the duration of the block.
+ The <literal>COLLATE</> option specifies a collation to use for the
+ variable (see <xref linkend="plpgsql-declaration-collation">).
If <literal>NOT NULL</>
is specified, an assignment of a null value results in a run-time
error. All variables declared as <literal>NOT NULL</>
</para>
<para>
- Explicit <literal>COLLATE</> clauses can be written inside a function
- if it is desired to force a particular collation to be used regardless
- of what the function is called with. For example,
+ A local variable of a collatable data type can have a different collation
+ associated with it by including the <literal>COLLATE</> option in its
+ declaration, for example
+
+<programlisting>
+DECLARE
+ local_a text COLLATE "en_US";
+</programlisting>
+
+ This option overrides the collation that would otherwise be
+ given to the variable according to the rules above.
+ </para>
+
+ <para>
+ Also, of course explicit <literal>COLLATE</> clauses can be written inside
+ a function if it is desired to force a particular collation to be used in
+ a particular operation. For example,
<programlisting>
CREATE FUNCTION less_than_c(a text, b text) RETURNS boolean AS $$
END;
$$ LANGUAGE plpgsql;
</programlisting>
+
+ This overrides the collations associated with the table columns,
+ parameters, or local variables used in the expression, just as would
+ happen in a plain SQL command.
</para>
</sect2>
</sect1>
#include "parser/parse_type.h"
#include "parser/scanner.h"
#include "parser/scansup.h"
+#include "utils/builtins.h"
/* Location tracking support --- simpler than bison's default */
PLcword cword;
PLwdatum wdatum;
bool boolean;
+ Oid oid;
struct
{
char *name;
%type <boolean> decl_const decl_notnull exit_type
%type <expr> decl_defval decl_cursor_query
%type <dtype> decl_datatype
+%type <oid> decl_collate
%type <datum> decl_cursor_args
%type <list> decl_cursor_arglist
%type <nsitem> decl_aliasitem
%token <keyword> K_BY
%token <keyword> K_CASE
%token <keyword> K_CLOSE
+%token <keyword> K_COLLATE
%token <keyword> K_CONSTANT
%token <keyword> K_CONTINUE
%token <keyword> K_CURSOR
}
;
-decl_statement : decl_varname decl_const decl_datatype decl_notnull decl_defval
+decl_statement : decl_varname decl_const decl_datatype decl_collate decl_notnull decl_defval
{
PLpgSQL_variable *var;
+ /*
+ * If a collation is supplied, insert it into the
+ * datatype. We assume decl_datatype always returns
+ * a freshly built struct not shared with other
+ * variables.
+ */
+ if (OidIsValid($4))
+ {
+ if (!OidIsValid($3->collation))
+ ereport(ERROR,
+ (errcode(ERRCODE_DATATYPE_MISMATCH),
+ errmsg("collations are not supported by type %s",
+ format_type_be($3->typoid)),
+ parser_errposition(@4)));
+ $3->collation = $4;
+ }
+
var = plpgsql_build_variable($1.name, $1.lineno,
$3, true);
if ($2)
errmsg("row or record variable cannot be CONSTANT"),
parser_errposition(@2)));
}
- if ($4)
+ if ($5)
{
if (var->dtype == PLPGSQL_DTYPE_VAR)
- ((PLpgSQL_var *) var)->notnull = $4;
+ ((PLpgSQL_var *) var)->notnull = $5;
else
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
parser_errposition(@4)));
}
- if ($5 != NULL)
+ if ($6 != NULL)
{
if (var->dtype == PLPGSQL_DTYPE_VAR)
- ((PLpgSQL_var *) var)->default_val = $5;
+ ((PLpgSQL_var *) var)->default_val = $6;
else
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
}
;
+decl_collate :
+ { $$ = InvalidOid; }
+ | K_COLLATE T_WORD
+ {
+ $$ = get_collation_oid(list_make1(makeString($2.ident)),
+ false);
+ }
+ | K_COLLATE T_CWORD
+ {
+ $$ = get_collation_oid($2.idents, false);
+ }
+ ;
+
decl_notnull :
{ $$ = false; }
| K_NOT K_NULL
yyerror("incomplete data type declaration");
}
/* Possible followers for datatype in a declaration */
- if (tok == K_NOT || tok == '=' || tok == COLON_EQUALS || tok == K_DEFAULT)
+ if (tok == K_COLLATE || tok == K_NOT ||
+ tok == '=' || tok == COLON_EQUALS || tok == K_DEFAULT)
break;
/* Possible followers for datatype in a cursor_arg list */
if ((tok == ',' || tok == ')') && parenlevel == 0)
PG_KEYWORD("by", K_BY, RESERVED_KEYWORD)
PG_KEYWORD("case", K_CASE, RESERVED_KEYWORD)
PG_KEYWORD("close", K_CLOSE, RESERVED_KEYWORD)
+ PG_KEYWORD("collate", K_COLLATE, RESERVED_KEYWORD)
PG_KEYWORD("continue", K_CONTINUE, RESERVED_KEYWORD)
PG_KEYWORD("declare", K_DECLARE, RESERVED_KEYWORD)
PG_KEYWORD("default", K_DEFAULT, RESERVED_KEYWORD)
bbc | bbc | f | f | f | f
(16 rows)
+-- collation override in plpgsql
+CREATE FUNCTION mylt2 (x text, y text) RETURNS boolean LANGUAGE plpgsql AS $$
+declare
+ xx text := x;
+ yy text := y;
+begin
+ return xx < yy;
+end
+$$;
+SELECT mylt2('a', 'B' collate "en_US") as t, mylt2('a', 'B' collate "C") as f;
+ t | f
+---+---
+ t | f
+(1 row)
+
+CREATE OR REPLACE FUNCTION
+ mylt2 (x text, y text) RETURNS boolean LANGUAGE plpgsql AS $$
+declare
+ xx text COLLATE "POSIX" := x;
+ yy text := y;
+begin
+ return xx < yy;
+end
+$$;
+SELECT mylt2('a', 'B') as f;
+ f
+---
+ f
+(1 row)
+
+SELECT mylt2('a', 'B' collate "C") as fail; -- conflicting collations
+ERROR: could not determine which collation to use for string comparison
+HINT: Use the COLLATE clause to set the collation explicitly.
+CONTEXT: PL/pgSQL function "mylt2" line 6 at RETURN
+SELECT mylt2('a', 'B' collate "POSIX") as f;
+ f
+---
+ f
+(1 row)
+
-- polymorphism
SELECT * FROM unnest((SELECT array_agg(b ORDER BY b) FROM collate_test1)) ORDER BY 1;
unnest
ORDER BY a.b, b.b;
+-- collation override in plpgsql
+
+CREATE FUNCTION mylt2 (x text, y text) RETURNS boolean LANGUAGE plpgsql AS $$
+declare
+ xx text := x;
+ yy text := y;
+begin
+ return xx < yy;
+end
+$$;
+
+SELECT mylt2('a', 'B' collate "en_US") as t, mylt2('a', 'B' collate "C") as f;
+
+CREATE OR REPLACE FUNCTION
+ mylt2 (x text, y text) RETURNS boolean LANGUAGE plpgsql AS $$
+declare
+ xx text COLLATE "POSIX" := x;
+ yy text := y;
+begin
+ return xx < yy;
+end
+$$;
+
+SELECT mylt2('a', 'B') as f;
+SELECT mylt2('a', 'B' collate "C") as fail; -- conflicting collations
+SELECT mylt2('a', 'B' collate "POSIX") as f;
+
+
-- polymorphism
SELECT * FROM unnest((SELECT array_agg(b ORDER BY b) FROM collate_test1)) ORDER BY 1;
projects / postgresql / commitdiff