Pokud se někdy ocitnete v situaci, kdy se chystáte provést uloženou proceduru, ale najednou se přistihnete. Říkáte si:„Kolik sloupců tato věc vrací? Které stoly? Dotazuje se na vzdálený server?“
Dobrou zprávou je, že existuje několik způsobů, jak tyto informace získat před spuštěním dotazu. Pojďme se na ně podívat.
Soubor sys.dm_exec_describe_first_result_set_for_object Funkce
První zastávkou je sys.dm_exec_describe_first_result_set_for_object funkce dynamického řízení systému.
Tato funkce má @object_id jako parametr a popisuje první metadata výsledku pro modul s tímto ID.
Lze jej použít na uložené procedury a spouštěče.
Zde je příklad k demonstraci. V tomto případě používám OBJECT_ID() funkce vrátit ID uložené procedury (což mě ušetří od nutnosti znát skutečné ID).
SELECT *
FROM sys.dm_exec_describe_first_result_set_for_object(
OBJECT_ID('spAlbumsFromArtist'),
0
); Výsledek:
+-------------+------------------+-------------+---------------+------------------+--------------------+--------------+-------------+---------+------------------------------+----------------+----------------------+--------------------+------------------+--------------------------------+---------------------+---------------------------+-------------------------+-----------------------+-------------------+---------------------+----------------------------+-----------------+-------------------+-----------------+----------------+-----------------+----------------------+-------------------------+-----------------+----------------------+------------------------+----------------------------+--------------------------+------------------------+----------------+------------------+---------------+-----------------+--------------+-------------------+ | is_hidden | column_ordinal | name | is_nullable | system_type_id | system_type_name | max_length | precision | scale | collation_name | user_type_id | user_type_database | user_type_schema | user_type_name | assembly_qualified_type_name | xml_collection_id | xml_collection_database | xml_collection_schema | xml_collection_name | is_xml_document | is_case_sensitive | is_fixed_length_clr_type | source_server | source_database | source_schema | source_table | source_column | is_identity_column | is_part_of_unique_key | is_updateable | is_computed_column | is_sparse_column_set | ordinal_in_order_by_list | order_by_is_descending | order_by_list_length | error_number | error_severity | error_state | error_message | error_type | error_type_desc | |-------------+------------------+-------------+---------------+------------------+--------------------+--------------+-------------+---------+------------------------------+----------------+----------------------+--------------------+------------------+--------------------------------+---------------------+---------------------------+-------------------------+-----------------------+-------------------+---------------------+----------------------------+-----------------+-------------------+-----------------+----------------+-----------------+----------------------+-------------------------+-----------------+----------------------+------------------------+----------------------------+--------------------------+------------------------+----------------+------------------+---------------+-----------------+--------------+-------------------| | 0 | 1 | AlbumName | 0 | 231 | nvarchar(255) | 510 | 0 | 0 | SQL_Latin1_General_CP1_CI_AS | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | 0 | 0 | 0 | NULL | NULL | NULL | NULL | NULL | 0 | NULL | 1 | 0 | 0 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | | 0 | 2 | ReleaseDate | 0 | 40 | date | 3 | 10 | 0 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | 0 | 0 | 0 | NULL | NULL | NULL | NULL | NULL | 0 | NULL | 1 | 0 | 0 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | +-------------+------------------+-------------+---------------+------------------+--------------------+--------------+-------------+---------+------------------------------+----------------+----------------------+--------------------+------------------+--------------------------------+---------------------+---------------------------+-------------------------+-----------------------+-------------------+---------------------+----------------------------+-----------------+-------------------+-----------------+----------------+-----------------+----------------------+-------------------------+-----------------+----------------------+------------------------+----------------------------+--------------------------+------------------------+----------------+------------------+---------------+-----------------+--------------+-------------------+
Pokud rolujete dostatečně do strany, uvidíte, že source_server , source_database , source_schema , source_table a source_column sloupce jsou NULL . Je to proto, že jsme použili 0 jako třetí argument.
Přepnutí třetího argumentu na 1 vrátí informace o základních tabulkách odkazovaných v uložené proceduře.
SELECT *
FROM sys.dm_exec_describe_first_result_set_for_object(
OBJECT_ID('spAlbumsFromArtist'),
1
); Výsledek:
+-------------+------------------+-------------+---------------+------------------+--------------------+--------------+-------------+---------+------------------------------+----------------+----------------------+--------------------+------------------+--------------------------------+---------------------+---------------------------+-------------------------+-----------------------+-------------------+---------------------+----------------------------+-----------------+-------------------+-----------------+----------------+-----------------+----------------------+-------------------------+-----------------+----------------------+------------------------+----------------------------+--------------------------+------------------------+----------------+------------------+---------------+-----------------+--------------+-------------------+ | is_hidden | column_ordinal | name | is_nullable | system_type_id | system_type_name | max_length | precision | scale | collation_name | user_type_id | user_type_database | user_type_schema | user_type_name | assembly_qualified_type_name | xml_collection_id | xml_collection_database | xml_collection_schema | xml_collection_name | is_xml_document | is_case_sensitive | is_fixed_length_clr_type | source_server | source_database | source_schema | source_table | source_column | is_identity_column | is_part_of_unique_key | is_updateable | is_computed_column | is_sparse_column_set | ordinal_in_order_by_list | order_by_is_descending | order_by_list_length | error_number | error_severity | error_state | error_message | error_type | error_type_desc | |-------------+------------------+-------------+---------------+------------------+--------------------+--------------+-------------+---------+------------------------------+----------------+----------------------+--------------------+------------------+--------------------------------+---------------------+---------------------------+-------------------------+-----------------------+-------------------+---------------------+----------------------------+-----------------+-------------------+-----------------+----------------+-----------------+----------------------+-------------------------+-----------------+----------------------+------------------------+----------------------------+--------------------------+------------------------+----------------+------------------+---------------+-----------------+--------------+-------------------| | 0 | 1 | AlbumName | 0 | 231 | nvarchar(255) | 510 | 0 | 0 | SQL_Latin1_General_CP1_CI_AS | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | 0 | 0 | 0 | Homer | Music | dbo | Albums | AlbumName | 0 | 0 | 1 | 0 | 0 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | | 0 | 2 | ReleaseDate | 0 | 40 | date | 3 | 10 | 0 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | 0 | 0 | 0 | Homer | Music | dbo | Albums | ReleaseDate | 0 | 0 | 1 | 0 | 0 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | | 1 | 3 | AlbumId | 0 | 56 | int | 4 | 10 | 0 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | 0 | 0 | 0 | Homer | Music | dbo | Albums | AlbumId | 0 | 1 | 1 | 0 | 0 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | | 1 | 4 | ArtistId | 0 | 56 | int | 4 | 10 | 0 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | 0 | 0 | 0 | Homer | Music | dbo | Artists | ArtistId | 0 | 1 | 1 | 0 | 0 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | +-------------+------------------+-------------+---------------+------------------+--------------------+--------------+-------------+---------+------------------------------+----------------+----------------------+--------------------+------------------+--------------------------------+---------------------+---------------------------+-------------------------+-----------------------+-------------------+---------------------+----------------------------+-----------------+-------------------+-----------------+----------------+-----------------+----------------------+-------------------------+-----------------+----------------------+------------------------+----------------------------+--------------------------+------------------------+----------------+------------------+---------------+-----------------+--------------+-------------------+
Nyní, když rolujeme do strany, vidíme, že source_server , source_database , source_schema , source_table a source_column všechny sloupce obsahují hodnoty.
V tomto případě se procedura dotazuje na tabulky přes propojený server s názvem „Homer“.
Také si všimnete, že nyní jsou vráceny čtyři řádky namísto pouhých dvou, které byly vráceny, když jsme nastavili třetí argument na 0 . Dva další řádky odrážejí základní sloupce, které jsou dotazovány v rámci uložené procedury.
Zde je definice uložené procedury:
CREATE PROCEDURE [dbo].[spAlbumsFromArtist]
@ArtistName varchar(255)
AS
SELECT AlbumName, ReleaseDate
FROM Homer.Music.dbo.Albums al
INNER JOIN Homer.Music.dbo.Artists ar
ON al.ArtistId = ar.ArtistId
WHERE ar.ArtistName = @ArtistName;I když tedy procedura vrací pouze dva sloupce, musí k dokončení svého úkolu odkazovat na další sloupce.
Viz Jak sys.dm_exec_describe_first_result_set_for_object Funguje pro více příkladů.
Set sys.dm_exec_describe_first_result_set Zobrazit
Toto zobrazení používá stejný algoritmus jako předchozí zobrazení a vrací stejné informace. Rozdíl je v tom, že analyzuje dávku T-SQL, nikoli skutečnou uloženou proceduru.
To znamená, že toto zobrazení můžete použít k analýze kódu, který nemusí být nutně v uložené proceduře nebo spouštěči. Můžete jej například použít k analýze zobrazení nebo dotazu ad hoc.
Ale tento článek je o analýze uložených procedur, takže zde je příklad, jak to udělat.
SELECT *
FROM sys.dm_exec_describe_first_result_set(
'EXEC spAlbumsFromArtist @ArtistId = ''Iron Maiden''',
null,
1
);Výsledek:
+-------------+------------------+-------------+---------------+------------------+--------------------+--------------+-------------+---------+------------------------------+----------------+----------------------+--------------------+------------------+--------------------------------+---------------------+---------------------------+-------------------------+-----------------------+-------------------+---------------------+----------------------------+-----------------+-------------------+-----------------+----------------+-----------------+----------------------+-------------------------+-----------------+----------------------+------------------------+----------------------------+--------------------------+------------------------+----------------+------------------+---------------+-----------------+--------------+-------------------+ | is_hidden | column_ordinal | name | is_nullable | system_type_id | system_type_name | max_length | precision | scale | collation_name | user_type_id | user_type_database | user_type_schema | user_type_name | assembly_qualified_type_name | xml_collection_id | xml_collection_database | xml_collection_schema | xml_collection_name | is_xml_document | is_case_sensitive | is_fixed_length_clr_type | source_server | source_database | source_schema | source_table | source_column | is_identity_column | is_part_of_unique_key | is_updateable | is_computed_column | is_sparse_column_set | ordinal_in_order_by_list | order_by_is_descending | order_by_list_length | error_number | error_severity | error_state | error_message | error_type | error_type_desc | |-------------+------------------+-------------+---------------+------------------+--------------------+--------------+-------------+---------+------------------------------+----------------+----------------------+--------------------+------------------+--------------------------------+---------------------+---------------------------+-------------------------+-----------------------+-------------------+---------------------+----------------------------+-----------------+-------------------+-----------------+----------------+-----------------+----------------------+-------------------------+-----------------+----------------------+------------------------+----------------------------+--------------------------+------------------------+----------------+------------------+---------------+-----------------+--------------+-------------------| | 0 | 1 | AlbumName | 0 | 231 | nvarchar(255) | 510 | 0 | 0 | SQL_Latin1_General_CP1_CI_AS | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | 0 | 0 | 0 | Homer | Music | dbo | Albums | AlbumName | 0 | 0 | 1 | 0 | 0 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | | 0 | 2 | ReleaseDate | 0 | 40 | date | 3 | 10 | 0 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | 0 | 0 | 0 | Homer | Music | dbo | Albums | ReleaseDate | 0 | 0 | 1 | 0 | 0 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | | 1 | 3 | AlbumId | 0 | 56 | int | 4 | 10 | 0 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | 0 | 0 | 0 | Homer | Music | dbo | Albums | AlbumId | 0 | 1 | 1 | 0 | 0 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | | 1 | 4 | ArtistId | 0 | 56 | int | 4 | 10 | 0 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | 0 | 0 | 0 | Homer | Music | dbo | Artists | ArtistId | 0 | 1 | 1 | 0 | 0 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | +-------------+------------------+-------------+---------------+------------------+--------------------+--------------+-------------+---------+------------------------------+----------------+----------------------+--------------------+------------------+--------------------------------+---------------------+---------------------------+-------------------------+-----------------------+-------------------+---------------------+----------------------------+-----------------+-------------------+-----------------+----------------+-----------------+----------------------+-------------------------+-----------------+----------------------+------------------------+----------------------------+--------------------------+------------------------+----------------+------------------+---------------+-----------------+--------------+-------------------+
Viz Jak sys.dm_exec_describe_first_result_set Funguje pro více příkladů.
Set sp_describe_first_result_set Uložená procedura systému
sp_describe_first_result_set systémová uložená procedura dělá to samé (a používá stejný algoritmus). Přijímá dávku T-SQL a vrací metadata pro svou první možnou sadu výsledků.
EXEC sp_describe_first_result_set
@tsql = N'EXEC spAlbumsFromArtist @ArtistId = ''Iron Maiden''',
@params = null,
@browse_information_mode = 1;Výsledek:
+-------------+------------------+-------------+---------------+------------------+--------------------+--------------+-------------+---------+------------------------------+----------------+----------------------+--------------------+------------------+--------------------------------+---------------------+---------------------------+-------------------------+-----------------------+-------------------+---------------------+----------------------------+-----------------+-------------------+-----------------+----------------+-----------------+----------------------+-------------------------+-----------------+----------------------+------------------------+----------------------------+--------------------------+------------------------+---------------+--------------+--------------------+-------------------------+ | is_hidden | column_ordinal | name | is_nullable | system_type_id | system_type_name | max_length | precision | scale | collation_name | user_type_id | user_type_database | user_type_schema | user_type_name | assembly_qualified_type_name | xml_collection_id | xml_collection_database | xml_collection_schema | xml_collection_name | is_xml_document | is_case_sensitive | is_fixed_length_clr_type | source_server | source_database | source_schema | source_table | source_column | is_identity_column | is_part_of_unique_key | is_updateable | is_computed_column | is_sparse_column_set | ordinal_in_order_by_list | order_by_is_descending | order_by_list_length | tds_type_id | tds_length | tds_collation_id | tds_collation_sort_id | |-------------+------------------+-------------+---------------+------------------+--------------------+--------------+-------------+---------+------------------------------+----------------+----------------------+--------------------+------------------+--------------------------------+---------------------+---------------------------+-------------------------+-----------------------+-------------------+---------------------+----------------------------+-----------------+-------------------+-----------------+----------------+-----------------+----------------------+-------------------------+-----------------+----------------------+------------------------+----------------------------+--------------------------+------------------------+---------------+--------------+--------------------+-------------------------| | 0 | 1 | AlbumName | 0 | 231 | nvarchar(255) | 510 | 0 | 0 | SQL_Latin1_General_CP1_CI_AS | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | 0 | 0 | 0 | Homer | Music | dbo | Albums | AlbumName | 0 | 0 | 1 | 0 | 0 | NULL | NULL | NULL | 231 | 510 | 13632521 | 52 | | 0 | 2 | ReleaseDate | 0 | 40 | date | 3 | 10 | 0 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | 0 | 0 | 0 | Homer | Music | dbo | Albums | ReleaseDate | 0 | 0 | 1 | 0 | 0 | NULL | NULL | NULL | 40 | 3 | NULL | NULL | | 1 | 3 | AlbumId | 0 | 56 | int | 4 | 10 | 0 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | 0 | 0 | 0 | Homer | Music | dbo | Albums | AlbumId | 0 | 1 | 1 | 0 | 0 | NULL | NULL | NULL | 56 | 4 | NULL | NULL | | 1 | 4 | ArtistId | 0 | 56 | int | 4 | 10 | 0 | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | NULL | 0 | 0 | 0 | Homer | Music | dbo | Artists | ArtistId | 0 | 1 | 1 | 0 | 0 | NULL | NULL | NULL | 56 | 4 | NULL | NULL | +-------------+------------------+-------------+---------------+------------------+--------------------+--------------+-------------+---------+------------------------------+----------------+----------------------+--------------------+------------------+--------------------------------+---------------------+---------------------------+-------------------------+-----------------------+-------------------+---------------------+----------------------------+-----------------+-------------------+-----------------+----------------+-----------------+----------------------+-------------------------+-----------------+----------------------+------------------------+----------------------------+--------------------------+------------------------+---------------+--------------+--------------------+-------------------------+
Viz Jak sp_describe_first_result_set Funguje pro více příkladů.
OPENROWSET s dočasnou tabulkou
Další možností je vytvořit dotaz, který umístí výsledky s horní nulou OPENROWSET dotaz do dočasné tabulky a poté použijte proceduru jako sp_columns vrátit informace o sloupci o této dočasné tabulce (která obsahuje data z naší sady výsledků).
Tím získáte podrobnosti, jako jsou názvy sloupců, datové typy atd.
SELECT TOP 0 * INTO #TempTable
FROM OPENROWSET(
'SQLNCLI',
'Server=localhost;Trusted_Connection=yes;',
'EXEC Test.dbo.sp_BadDogs');
EXEC('USE tempdb EXEC sp_columns #TempTable DROP TABLE #TempTable');Výsledek:
+-------------------+---------------+----------------------------------------------------------------------------------------------------------------------------------+---------------+-------------+-------------+-------------+----------+---------+---------+------------+-----------+--------------+-----------------+--------------------+---------------------+--------------------+---------------+----------------+ | TABLE_QUALIFIER | TABLE_OWNER | TABLE_NAME | COLUMN_NAME | DATA_TYPE | TYPE_NAME | PRECISION | LENGTH | SCALE | RADIX | NULLABLE | REMARKS | COLUMN_DEF | SQL_DATA_TYPE | SQL_DATETIME_SUB | CHAR_OCTET_LENGTH | ORDINAL_POSITION | IS_NULLABLE | SS_DATA_TYPE | |-------------------+---------------+----------------------------------------------------------------------------------------------------------------------------------+---------------+-------------+-------------+-------------+----------+---------+---------+------------+-----------+--------------+-----------------+--------------------+---------------------+--------------------+---------------+----------------| | tempdb | dbo | #TempTable__________________________________________________________________________________________________________000000000017 | DogId | 4 | int | 10 | 4 | 0 | 10 | 0 | NULL | NULL | 4 | NULL | NULL | 1 | NO | 56 | | tempdb | dbo | #TempTable__________________________________________________________________________________________________________000000000017 | DogName | -9 | nvarchar | 255 | 510 | NULL | NULL | 1 | NULL | NULL | -9 | NULL | 510 | 2 | YES | 39 | | tempdb | dbo | #TempTable__________________________________________________________________________________________________________000000000017 | GoodDog | -7 | bit | 1 | 1 | NULL | NULL | 1 | NULL | NULL | -7 | NULL | NULL | 3 | YES | 50 | +-------------------+---------------+----------------------------------------------------------------------------------------------------------------------------------+---------------+-------------+-------------+-------------+----------+---------+---------+------------+-----------+--------------+-----------------+--------------------+---------------------+--------------------+---------------+----------------+
Pomocí této metody můžete také dělat věci, jako je zaměnit sp_columns pro sp_help nebo podobně.