在做一个项目用到了pgsql,然后在实例化模型的时候报错了个错，报错信息:7:ERROR: function table_msg(unknown) does not exist LINE 1: ...fault as "default",fields_default as "extra" from table_msg(... ^ HINT: No function matches the given name and argument types. You might need to add explicit type casts. [ SQL语句 ] : select fields_name as "field",fields_type as "type",fields_not_null as "null",fields_key_name as "key",fields_default as "default",fields_default as "extra" from table_msg('admin');

，在网上查了一些资料后，看到一个帖子是这样写的：
CREATE OR REPLACE FUNCTION pgsql_type(a_type varchar) RETURNS varchar AS
$BODY$
DECLARE
v_type varchar;
BEGIN
IF a_type='int8' THEN
v_type:='bigint';
ELSIF a_type='int4' THEN
v_type:='integer';
ELSIF a_type='int2' THEN
v_type:='smallint';
ELSIF a_type='bpchar' THEN
v_type:='char';
ELSE
v_type:=a_type;
END IF;
RETURN v_type;
END;
$BODY$
LANGUAGE PLPGSQL;

CREATE TYPE "public"."tablestruct" AS (
"fields_key_name" varchar(100),
"fields_name" VARCHAR(200),
"fields_type" VARCHAR(20),
"fields_length" BIGINT,
"fields_not_null" VARCHAR(10),
"fields_default" VARCHAR(500),
"fields_comment" VARCHAR(1000)
);

CREATE OR REPLACE FUNCTION "public"."table_msg" (a_schema_name varchar, a_table_name varchar) RETURNS SETOF "public"."tablestruct" AS
$body$
DECLARE
v_ret tablestruct;
v_oid oid;
v_sql varchar;
v_rec RECORD;
v_key varchar;
BEGIN
SELECT
pg_class.oid INTO v_oid
FROM
pg_class
INNER JOIN pg_namespace ON (pg_class.relnamespace = pg_namespace.oid AND lower(pg_namespace.nspname) = a_schema_name)
WHERE
pg_class.relname=a_table_name;
IF NOT FOUND THEN
RETURN;
END IF;

v_sql='
SELECT
pg_attribute.attname AS fields_name,
pg_attribute.attnum AS fields_index,
pgsql_type(pg_type.typname::varchar) AS fields_type,
pg_attribute.atttypmod-4 as fields_length,
CASE WHEN pg_attribute.attnotnull THEN ''not null''
ELSE ''''
END AS fields_not_null,
pg_attrdef.adsrc AS fields_default,
pg_description.description AS fields_comment
FROM
pg_attribute
INNER JOIN pg_class ON pg_attribute.attrelid = pg_class.oid
INNER JOIN pg_type ON pg_attribute.atttypid = pg_type.oid
LEFT OUTER JOIN pg_attrdef ON pg_attrdef.adrelid = pg_class.oid AND pg_attrdef.adnum = pg_attribute.attnum
LEFT OUTER JOIN pg_description ON pg_description.objoid = pg_class.oid AND pg_description.objsubid = pg_attribute.attnum
WHERE
pg_attribute.attnum > 0
AND attisdropped <> ''t''
AND pg_class.oid = ' || v_oid || '
ORDER BY pg_attribute.attnum' ;

FOR v_rec IN EXECUTE v_sql LOOP
v_ret.fields_name=v_rec.fields_name;
v_ret.fields_type=v_rec.fields_type;
IF v_rec.fields_length > 0 THEN
v_ret.fields_length:=v_rec.fields_length;
ELSE
v_ret.fields_length:=NULL;
END IF;
v_ret.fields_not_null=v_rec.fields_not_null;
v_ret.fields_default=v_rec.fields_default;
v_ret.fields_comment=v_rec.fields_comment;
SELECT constraint_name INTO v_key FROM information_schema.key_column_usage WHERE table_schema=a_schema_name AND table_name=a_table_name AND column_name=v_rec.fields_name;
IF FOUND THEN
v_ret.fields_key_name=v_key;
ELSE
v_ret.fields_key_name='';
END IF;
RETURN NEXT v_ret;
END LOOP;
RETURN ;
END;
$body$
LANGUAGE 'plpgsql' VOLATILE CALLED ON NULL INPUT SECURITY INVOKER;

COMMENT ON FUNCTION "public"."table_msg"(a_schema_name varchar, a_table_name varchar)
IS '获得表信息';

---重载一个函数
CREATE OR REPLACE FUNCTION "public"."table_msg" (a_table_name varchar) RETURNS SETOF "public"."tablestruct" AS
$body$
DECLARE
v_ret tablestruct;
BEGIN
FOR v_ret IN SELECT * FROM table_msg('public',a_table_name) LOOP
RETURN NEXT v_ret;
END LOOP;
RETURN;
END;
$body$
LANGUAGE 'plpgsql' VOLATILE CALLED ON NULL INPUT SECURITY INVOKER;

COMMENT ON FUNCTION "public"."table_msg"(a_table_name varchar)
IS '获得表信息';

把那段代码执行以下就可以不报错了，很是不解放在哪里怎么执行？ 求大神指点。