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In plpgsql, allow %TYPE and %ROWTYPE to be followed by array decoration.

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This provides the useful ability to declare a variable that is an array
of the type of some other variable or some table column.

Quan Zongliang, Pavel Stehule

Discussion: https://postgr.es/m/ec4523e1-9e7e-f3ef-f9ce-bafd680ad6f6@yeah.net
This commit is contained in:
Tom Lane 2024-01-04 15:24:15 -05:00
parent 5d06e99a3c
commit 5e8674dc83
6 changed files with 261 additions and 32 deletions
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29
doc/src/sgml/plpgsql.sgml
View File

@ -675,12 +675,14 @@ DECLARE
<title>Copying Types</title>
<synopsis>
<replaceable>variable</replaceable>%TYPE
<replaceable>name</replaceable> <replaceable>table</replaceable>.<replaceable>column</replaceable>%TYPE
<replaceable>name</replaceable> <replaceable>variable</replaceable>%TYPE
</synopsis>
<para>
<literal>%TYPE</literal> provides the data type of a variable or
table column. You can use this to declare variables that will hold
<literal>%TYPE</literal> provides the data type of a table column
or a previously-declared <application>PL/pgSQL</application>
variable. You can use this to declare variables that will hold
database values. For example, let's say you have a column named
<literal>user_id</literal> in your <literal>users</literal>
table. To declare a variable with the same data type as
@ -690,6 +692,21 @@ user_id users.user_id%TYPE;
</programlisting>
</para>
<para>
It is also possible to write array decoration
after <literal>%TYPE</literal>, thereby creating a variable that holds
an array of the referenced type:
<programlisting>
user_ids users.user_id%TYPE[];
user_ids users.user_id%TYPE ARRAY[4]; -- equivalent to the above
</programlisting>
Just as when declaring table columns that are arrays, it doesn't
matter whether you write multiple bracket pairs or specific array
dimensions: <productname>PostgreSQL</productname> treats all arrays of
a given element type as the same type, regardless of dimensionality.
(See <xref linkend="arrays-declaration"/>.)
</para>
<para>
By using <literal>%TYPE</literal> you don't need to know the data
type of the structure you are referencing, and most importantly,
@ -739,6 +756,12 @@ user_id users.user_id%TYPE;
<literal>%ROWTYPE</literal> is more portable.)
</para>
<para>
As with <literal>%TYPE</literal>, <literal>%ROWTYPE</literal> can be
followed by array decoration to declare a variable that holds an array
of the referenced composite type.
</para>
<para>
Parameters to a function can be
composite types (complete table rows). In that case, the

79
src/pl/plpgsql/src/expected/plpgsql_array.out
View File

@ -93,3 +93,82 @@ LINE 1: a.r[1] := 2
^
QUERY: a.r[1] := 2
CONTEXT: PL/pgSQL function inline_code_block line 2 at assignment
--
-- test of %type[] and %rowtype[] syntax
--
-- check supported syntax
do $$
declare
v int;
v1 v%type;
v2 v%type[];
v3 v%type[1];
v4 v%type[][];
v5 v%type[1][3];
v6 v%type array;
v7 v%type array[];
v8 v%type array[1];
v9 v%type array[1][1];
v10 pg_catalog.pg_class%rowtype[];
begin
raise notice '%', pg_typeof(v1);
raise notice '%', pg_typeof(v2);
raise notice '%', pg_typeof(v3);
raise notice '%', pg_typeof(v4);
raise notice '%', pg_typeof(v5);
raise notice '%', pg_typeof(v6);
raise notice '%', pg_typeof(v7);
raise notice '%', pg_typeof(v8);
raise notice '%', pg_typeof(v9);
raise notice '%', pg_typeof(v10);
end;
$$;
NOTICE: integer
NOTICE: integer[]
NOTICE: integer[]
NOTICE: integer[]
NOTICE: integer[]
NOTICE: integer[]
NOTICE: integer[]
NOTICE: integer[]
NOTICE: integer[]
NOTICE: pg_class[]
-- some types don't support arrays
do $$
declare
v pg_node_tree;
v1 v%type[];
begin
end;
$$;
ERROR: could not find array type for data type pg_node_tree
CONTEXT: compilation of PL/pgSQL function "inline_code_block" near line 4
-- check functionality
do $$
declare
v1 int;
v2 varchar;
a1 v1%type[];
a2 v2%type[];
begin
v1 := 10;
v2 := 'Hi';
a1 := array[v1,v1];
a2 := array[v2,v2];
raise notice '% %', a1, a2;
end;
$$;
NOTICE: {10,10} {Hi,Hi}
create table array_test_table(a int, b varchar);
insert into array_test_table values(1, 'first'), (2, 'second');
do $$
declare tg array_test_table%rowtype[];
begin
tg := array(select array_test_table from array_test_table);
raise notice '%', tg;
tg := array(select row(a,b) from array_test_table);
raise notice '%', tg;
end;
$$;
NOTICE: {"(1,first)","(2,second)"}
NOTICE: {"(1,first)","(2,second)"}

27
src/pl/plpgsql/src/pl_comp.c
View File

@ -2208,6 +2208,33 @@ build_datatype(HeapTuple typeTup, int32 typmod,
return typ;
}
/*
* Build an array type for the element type specified as argument.
*/
PLpgSQL_type *
plpgsql_build_datatype_arrayof(PLpgSQL_type *dtype)
{
Oid array_typeid;
/*
* If it's already an array type, use it as-is: Postgres doesn't do nested
* arrays.
*/
if (dtype->typisarray)
return dtype;
array_typeid = get_array_type(dtype->typoid);
if (!OidIsValid(array_typeid))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("could not find array type for data type %s",
format_type_be(dtype->typoid))));
/* Note we inherit typmod and collation, if any, from the element type */
return plpgsql_build_datatype(array_typeid, dtype->atttypmod,
dtype->collation, NULL);
}
/*
* plpgsql_recognize_err_condition
* Check condition name and translate it to SQLSTATE.

86
src/pl/plpgsql/src/pl_gram.y
View File

@ -757,8 +757,9 @@ decl_const :
decl_datatype :
{
/*
* If there's a lookahead token, read_datatype
* should consume it.
* If there's a lookahead token, read_datatype() will
* consume it, and then we must tell bison to forget
* it.
*/
$$ = read_datatype(yychar);
yyclearin;
@ -2783,13 +2784,17 @@ read_sql_construct(int until,
return expr;
}
/*
* Read a datatype declaration, consuming the current lookahead token if any.
* Returns a PLpgSQL_type struct.
*/
static PLpgSQL_type *
read_datatype(int tok)
{
StringInfoData ds;
char *type_name;
int startlocation;
PLpgSQL_type *result;
PLpgSQL_type *result = NULL;
int parenlevel = 0;
/* Should only be called while parsing DECLARE sections */
@ -2799,11 +2804,15 @@ read_datatype(int tok)
if (tok == YYEMPTY)
tok = yylex();
/* The current token is the start of what we'll pass to parse_datatype */
startlocation = yylloc;
/*
* If we have a simple or composite identifier, check for %TYPE
* and %ROWTYPE constructs.
* If we have a simple or composite identifier, check for %TYPE and
* %ROWTYPE constructs. (Note that if plpgsql_parse_wordtype et al fail
* to recognize the identifier, we'll fall through and pass the whole
* string to parse_datatype, which will assuredly give an unhelpful
* "syntax error". Should we try to give a more specific error?)
*/
if (tok == T_WORD)
{
@ -2815,18 +2824,10 @@ read_datatype(int tok)
tok = yylex();
if (tok_is_keyword(tok, &yylval,
K_TYPE, "type"))
{
result = plpgsql_parse_wordtype(dtname);
if (result)
return result;
}
else if (tok_is_keyword(tok, &yylval,
K_ROWTYPE, "rowtype"))
{
result = plpgsql_parse_wordrowtype(dtname);
if (result)
return result;
}
}
}
else if (plpgsql_token_is_unreserved_keyword(tok))
@ -2839,18 +2840,10 @@ read_datatype(int tok)
tok = yylex();
if (tok_is_keyword(tok, &yylval,
K_TYPE, "type"))
{
result = plpgsql_parse_wordtype(dtname);
if (result)
return result;
}
else if (tok_is_keyword(tok, &yylval,
K_ROWTYPE, "rowtype"))
{
result = plpgsql_parse_wordrowtype(dtname);
if (result)
return result;
}
}
}
else if (tok == T_CWORD)
@ -2863,21 +2856,56 @@ read_datatype(int tok)
tok = yylex();
if (tok_is_keyword(tok, &yylval,
K_TYPE, "type"))
{
result = plpgsql_parse_cwordtype(dtnames);
if (result)
return result;
}
else if (tok_is_keyword(tok, &yylval,
K_ROWTYPE, "rowtype"))
{
result = plpgsql_parse_cwordrowtype(dtnames);
if (result)
return result;
}
}
}
/*
* If we recognized a %TYPE or %ROWTYPE construct, see if it is followed
* by array decoration: [ ARRAY ] [ '[' [ iconst ] ']' [ ... ] ]
*
* Like the core parser, we ignore the specific numbers and sizes of
* dimensions; arrays of different dimensionality are still the same type
* in Postgres.
*/
if (result)
{
bool is_array = false;
tok = yylex();
if (tok_is_keyword(tok, &yylval,
K_ARRAY, "array"))
{
is_array = true;
tok = yylex();
}
while (tok == '[')
{
is_array = true;
tok = yylex();
if (tok == ICONST)
tok = yylex();
if (tok != ']')
yyerror("syntax error, expected \"]\"");
tok = yylex();
}
plpgsql_push_back_token(tok);
if (is_array)
result = plpgsql_build_datatype_arrayof(result);
return result;
}
/*
* Not %TYPE or %ROWTYPE, so scan to the end of the datatype declaration,
* which could include typmod or array decoration. We are not very picky
* here, instead relying on parse_datatype to complain about garbage. But
* we must count parens to handle typmods within cursor_arg correctly.
*/
while (tok != ';')
{
if (tok == 0)

1
src/pl/plpgsql/src/plpgsql.h
View File

@ -1249,6 +1249,7 @@ extern PLpgSQL_type *plpgsql_parse_cwordrowtype(List *idents);
extern PGDLLEXPORT PLpgSQL_type *plpgsql_build_datatype(Oid typeOid, int32 typmod,
Oid collation,
TypeName *origtypname);
extern PLpgSQL_type *plpgsql_build_datatype_arrayof(PLpgSQL_type *dtype);
extern PLpgSQL_variable *plpgsql_build_variable(const char *refname, int lineno,
PLpgSQL_type *dtype,
bool add2namespace);

71
src/pl/plpgsql/src/sql/plpgsql_array.sql
View File

@ -77,3 +77,74 @@ begin a[1] := 2; raise notice 'a = %', a; end$$;
do $$ declare a complex;
begin a.r[1] := 2; raise notice 'a = %', a; end$$;
--
-- test of %type[] and %rowtype[] syntax
--
-- check supported syntax
do $$
declare
v int;
v1 v%type;
v2 v%type[];
v3 v%type[1];
v4 v%type[][];
v5 v%type[1][3];
v6 v%type array;
v7 v%type array[];
v8 v%type array[1];
v9 v%type array[1][1];
v10 pg_catalog.pg_class%rowtype[];
begin
raise notice '%', pg_typeof(v1);
raise notice '%', pg_typeof(v2);
raise notice '%', pg_typeof(v3);
raise notice '%', pg_typeof(v4);
raise notice '%', pg_typeof(v5);
raise notice '%', pg_typeof(v6);
raise notice '%', pg_typeof(v7);
raise notice '%', pg_typeof(v8);
raise notice '%', pg_typeof(v9);
raise notice '%', pg_typeof(v10);
end;
$$;
-- some types don't support arrays
do $$
declare
v pg_node_tree;
v1 v%type[];
begin
end;
$$;
-- check functionality
do $$
declare
v1 int;
v2 varchar;
a1 v1%type[];
a2 v2%type[];
begin
v1 := 10;
v2 := 'Hi';
a1 := array[v1,v1];
a2 := array[v2,v2];
raise notice '% %', a1, a2;
end;
$$;
create table array_test_table(a int, b varchar);
insert into array_test_table values(1, 'first'), (2, 'second');
do $$
declare tg array_test_table%rowtype[];
begin
tg := array(select array_test_table from array_test_table);
raise notice '%', tg;
tg := array(select row(a,b) from array_test_table);
raise notice '%', tg;
end;
$$;