我想在postgresql数据库中编写关于函数的精美详细的报告。 我构建了以下查询：
SELECT routine_name, data_type, proargnames
FROM information_schema.routines
join pg_catalog.pg_proc on pg_catalog.pg_proc.proname = information_schema.routines.routine_name
WHERE specific_schema = 'public'
ORDER BY routine_name;
它应该工作（基本上返回我想要的东西：函数名，输出数据类型和输入数据类型），除了一件事：
我有相对复杂的函数，其中许多函数返回record。
问题是，data_type也为这些函数返回record，而我想要详细的函数输出类型列表。
例如，我在我的一个函数中有类似的东西：
RETURNS TABLE("Res" integer, "Output" character varying) AS
如何在上面进行查询（或者，如果它可以解决问题，可能是新查询）返回类似的内容
这些功能integer, character varying代替record？
我正在使用postgresql 9.2
提前谢谢！
答案 0 :(得分：1)
在运行时评估RECORD返回的值，无法以这种方式检索信息。
但是，如果使用RETURNS TABLE("Res" integer, "Output" character varying) AS，则有一个解决方案。
我使用的测试功能：
-- first function, uses RETURNS TABLE
CREATE FUNCTION test_ret(a TEXT, b TEXT)
RETURNS TABLE("Res" integer, "Output" character varying) AS $$
DECLARE
ret RECORD;
BEGIN
-- test
END;$$ LANGUAGE plpgsql;
-- second function, test some edge cases
-- same name as above, returns simple integer
CREATE FUNCTION test_ret(a TEXT)
RETURNS INTEGER AS $$
DECLARE
ret RECORD;
BEGIN
-- test
END;$$ LANGUAGE plpgsql;
如何检索此函数返回数据类型很容易，因为它存储在pg_catalog.pg_proc.proallargtypes中，问题是这是一个OID数组。我们必须删除此内容并将其加入pg_catalog.pg_types.oid。
-- edit: add support for function not returning tables, thx Tommaso Di Bucchianico
WITH pg_proc_with_unnested_proallargtypes AS (
SELECT
pg_catalog.pg_proc.oid,
pg_catalog.pg_proc.proname,
CASE WHEN proallargtypes IS NOT NULL THEN unnest(proallargtypes) ELSE null END AS proallargtype
FROM pg_catalog.pg_proc
JOIN pg_catalog.pg_namespace ON pg_catalog.pg_proc.pronamespace = pg_catalog.pg_namespace.oid
WHERE pg_catalog.pg_namespace.nspname = 'public'
),
pg_proc_with_proallargtypes_names AS (
SELECT
pg_proc_with_unnested_proallargtypes.oid,
pg_proc_with_unnested_proallargtypes.proname,
array_agg(pg_catalog.pg_type.typname) AS proallargtypes
FROM pg_proc_with_unnested_proallargtypes
LEFT JOIN pg_catalog.pg_type ON pg_catalog.pg_type.oid = proallargtype
GROUP BY
pg_proc_with_unnested_proallargtypes.oid,
pg_proc_with_unnested_proallargtypes.proname
)
SELECT
information_schema.routines.specific_name,
information_schema.routines.routine_name,
information_schema.routines.routine_schema,
information_schema.routines.data_type,
pg_proc_with_proallargtypes_names.proallargtypes
FROM information_schema.routines
-- we can declare many function with the same name and schema as long as arg types are different
-- This is the only right way to join pg_catalog.pg_proc and information_schema.routines, sadly
JOIN pg_proc_with_proallargtypes_names
ON pg_proc_with_proallargtypes_names.proname || '_' || pg_proc_with_proallargtypes_names.oid = information_schema.routines.specific_name
;
欢迎任何重构：）
结果如下：
specific_name | routine_name | routine_schema | data_type | proallargtypes
----------------+--------------+----------------+-----------+--------------------------
test_ret_16633 | test_ret | public | record | {text,text,int4,varchar}
test_ret_16635 | test_ret | public | integer | {NULL}
(2 rows)
修改 输入和输出参数的识别并不简单，这是我对pg 9.2的解决方案
-- https://gist.github.com/subssn21/e9e121f6fd5ff50f688d
-- Allow us to use array_remove in pg < 9.3
CREATE OR REPLACE FUNCTION array_remove(a ANYARRAY, e ANYELEMENT)
RETURNS ANYARRAY AS $$
BEGIN
RETURN array(SELECT x FROM unnest(a) x WHERE x <> e);
END;
$$ LANGUAGE plpgsql;
-- edit: add support for function not returning tables, thx Tommaso Di Bucchianico
WITH pg_proc_with_unnested_proallargtypes AS (
SELECT
pg_catalog.pg_proc.oid,
pg_catalog.pg_proc.proname,
pg_catalog.pg_proc.proargmodes,
CASE WHEN proallargtypes IS NOT NULL THEN unnest(proallargtypes) ELSE null END AS proallargtype
FROM pg_catalog.pg_proc
JOIN pg_catalog.pg_namespace ON pg_catalog.pg_proc.pronamespace = pg_catalog.pg_namespace.oid
WHERE pg_catalog.pg_namespace.nspname = 'public'
),
pg_proc_with_unnested_proallargtypes_names_and_mode AS (
SELECT
pg_proc_with_unnested_proallargtypes.oid,
pg_proc_with_unnested_proallargtypes.proname,
pg_catalog.pg_type.typname,
-- we can't unnest multiple array of same length the way we expect in pg 9.2
-- just retrieve each mode manually using type row_number
pg_proc_with_unnested_proallargtypes.proargmodes[row_number() OVER w] AS proargmode
FROM pg_proc_with_unnested_proallargtypes
LEFT JOIN pg_catalog.pg_type ON pg_catalog.pg_type.oid = proallargtype
WINDOW w AS (PARTITION BY pg_proc_with_unnested_proallargtypes.proname)
),
pg_proc_with_input_and_output_type_names AS (
SELECT
pg_proc_with_unnested_proallargtypes_names_and_mode.oid,
pg_proc_with_unnested_proallargtypes_names_and_mode.proname,
array_agg(pg_proc_with_unnested_proallargtypes_names_and_mode.typname) AS proallargtypes,
-- we should use FILTER, but that's not available in pg 9.2 :(
array_remove(array_agg(
-- see documentation for proargmodes here: http://www.postgresql.org/docs/9.2/static/catalog-pg-proc.html
CASE WHEN pg_proc_with_unnested_proallargtypes_names_and_mode.proargmode = ANY(ARRAY['i', 'b', 'v'])
THEN pg_proc_with_unnested_proallargtypes_names_and_mode.typname
ELSE NULL END
), NULL) AS proinputargtypes,
array_remove(array_agg(
-- see documentation for proargmodes here: http://www.postgresql.org/docs/9.2/static/catalog-pg-proc.html
CASE WHEN pg_proc_with_unnested_proallargtypes_names_and_mode.proargmode = ANY(ARRAY['o', 'b', 't'])
THEN pg_proc_with_unnested_proallargtypes_names_and_mode.typname
ELSE NULL END
), NULL) AS prooutputargtypes
FROM pg_proc_with_unnested_proallargtypes_names_and_mode
GROUP BY
pg_proc_with_unnested_proallargtypes_names_and_mode.oid,
pg_proc_with_unnested_proallargtypes_names_and_mode.proname
)
SELECT
*
FROM pg_proc_with_input_and_output_type_names
;
这是我的示例输出：
oid | proname | proallargtypes | proinputargtypes | prooutputargtypes
-------+--------------+--------------------------+------------------+-------------------
16633 | test_ret | {text,text,int4,varchar} | {text,text} | {int4,varchar}
16634 | array_remove | {NULL} | {} | {}
16635 | test_ret | {NULL} | {} | {}
(3 rows)
希望有所帮助：）