postgesql 数据库如何获取存储过程列列表信息还有参数定义

前言

要写这个。。恩。确实有用的。
下面是参考资料：
postgresql_meta_info
文章中提到：

SELECT proname
  FROM pg_proc pr,
       pg_type tp
 WHERE tp.oid = pr.prorettype
   AND pr.proisagg = FALSE
   AND tp.typname <> 'trigger'
   AND pr.pronamespace IN (
       SELECT oid
         FROM pg_namespace
        WHERE nspname NOT LIKE 'pg_%'
          AND nspname != 'information_schema'
);
 
-- with INFORMATION_SCHEMA:
 
SELECT routine_name
  FROM information_schema.routines
 WHERE specific_schema NOT IN
       ('pg_catalog', 'information_schema')
   AND type_udt_name != 'trigger';

CREATE OR REPLACE FUNCTION public.function_args(
  IN funcname character varying,
  IN schema character varying,
  OUT pos integer,
  OUT direction character,
  OUT argname character varying,
  OUT datatype character varying)
RETURNS SETOF RECORD AS $$DECLARE
  rettype character varying;
  argtypes oidvector;
  allargtypes oid[];
  argmodes "char"[];
  argnames text[];
  mini integer;
  maxi integer;
BEGIN
  /* get object ID of function */
  SELECT INTO rettype, argtypes, allargtypes, argmodes, argnames
         CASE
         WHEN pg_proc.proretset
         THEN 'setof ' || pg_catalog.format_type(pg_proc.prorettype, NULL)
         ELSE pg_catalog.format_type(pg_proc.prorettype, NULL) END,
         pg_proc.proargtypes,
         pg_proc.proallargtypes,
         pg_proc.proargmodes,
         pg_proc.proargnames
    FROM pg_catalog.pg_proc
         JOIN pg_catalog.pg_namespace
         ON (pg_proc.pronamespace = pg_namespace.oid)
   WHERE pg_proc.prorettype <> 'pg_catalog.cstring'::pg_catalog.regtype
     AND (pg_proc.proargtypes[0] IS NULL
      OR pg_proc.proargtypes[0] <> 'pg_catalog.cstring'::pg_catalog.regtype)
     AND NOT pg_proc.proisagg
     AND pg_proc.proname = funcname
     AND pg_namespace.nspname = schema
     AND pg_catalog.pg_function_is_visible(pg_proc.oid);
 
  /* bail out if not found */
  IF NOT FOUND THEN
    RETURN;
  END IF;
 
  /* return a row for the return value */
  pos = 0;
  direction = 'o'::char;
  argname = 'RETURN VALUE';
  datatype = rettype;
  RETURN NEXT;
 
  /* unfortunately allargtypes is NULL if there are no OUT parameters */
  IF allargtypes IS NULL THEN
    mini = array_lower(argtypes, 1); maxi = array_upper(argtypes, 1);
  ELSE
    mini = array_lower(allargtypes, 1); maxi = array_upper(allargtypes, 1);
  END IF;
  IF maxi < mini THEN RETURN; END IF;
 
  /* loop all the arguments */
  FOR i IN mini .. maxi LOOP
    pos = i - mini + 1;
    IF argnames IS NULL THEN
      argname = NULL;
    ELSE
      argname = argnames[pos];
    END IF;
    IF allargtypes IS NULL THEN
      direction = 'i'::char;
      datatype = pg_catalog.format_type(argtypes[i], NULL);
    ELSE
      direction = argmodes[i];
      datatype = pg_catalog.format_type(allargtypes[i], NULL);
    END IF;
    RETURN NEXT;
  END LOOP;
 
  RETURN;
END;$$ LANGUAGE plpgsql STABLE STRICT SECURITY INVOKER;
COMMENT ON FUNCTION public.function_args(character varying, character
varying)
IS $$For a function name and schema, this procedure selects for each
argument the following data:
- position in the argument list (0 for the return value)
- direction 'i', 'o', or 'b'
- name (NULL if not defined)
- data type$$;