Si alguna vez se encuentra en la situación en la que está a punto de ejecutar un procedimiento almacenado, pero de repente se encuentra. Te preguntas “¿Cuántas columnas devuelve esta cosa? ¿Qué mesas? ¿Consulta un servidor remoto?”
La buena noticia es que hay varias formas de obtener esta información antes de ejecutar la consulta. Veámoslos.
El sys.dm_exec_describe_first_result_set_for_object Función
La primera parada es sys.dm_exec_describe_first_result_set_for_object función de gestión dinámica del sistema.
Esta función toma un @object_id como parámetro y describe los metadatos del primer resultado para el módulo con esa ID.
Se puede usar en procedimientos almacenados y disparadores.
Aquí hay un ejemplo para demostrar. En este caso, uso el OBJECT_ID() para devolver la ID del procedimiento almacenado (lo que me evita tener que saber la ID real).
SELECT *
FROM sys.dm_exec_describe_first_result_set_for_object(
OBJECT_ID('spAlbumsFromArtist'),
0
); Resultado:
+-------------+------------------+-------------+---------------+------------------+--------------------+--------------+-------------+---------+------------------------------+----------------+----------------------+--------------------+------------------+--------------------------------+---------------------+---------------------------+-------------------------+-----------------------+-------------------+---------------------+----------------------------+-----------------+-------------------+-----------------+----------------+-----------------+----------------------+-------------------------+-----------------+----------------------+------------------------+----------------------------+--------------------------+------------------------+----------------+------------------+---------------+-----------------+--------------+-------------------+ | 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 | +-------------+------------------+-------------+---------------+------------------+--------------------+--------------+-------------+---------+------------------------------+----------------+----------------------+--------------------+------------------+--------------------------------+---------------------+---------------------------+-------------------------+-----------------------+-------------------+---------------------+----------------------------+-----------------+-------------------+-----------------+----------------+-----------------+----------------------+-------------------------+-----------------+----------------------+------------------------+----------------------------+--------------------------+------------------------+----------------+------------------+---------------+-----------------+--------------+-------------------+
Si se desplaza lo suficiente hacia los lados, verá que el source_server , source_database , source_schema , source_table y source_column las columnas son NULL . Esto se debe a que usamos 0 como tercer argumento.
Cambiar el tercer argumento a 1 devolverá información sobre las tablas base a las que se hace referencia en el procedimiento almacenado.
SELECT *
FROM sys.dm_exec_describe_first_result_set_for_object(
OBJECT_ID('spAlbumsFromArtist'),
1
); Resultado:
+-------------+------------------+-------------+---------------+------------------+--------------------+--------------+-------------+---------+------------------------------+----------------+----------------------+--------------------+------------------+--------------------------------+---------------------+---------------------------+-------------------------+-----------------------+-------------------+---------------------+----------------------------+-----------------+-------------------+-----------------+----------------+-----------------+----------------------+-------------------------+-----------------+----------------------+------------------------+----------------------------+--------------------------+------------------------+----------------+------------------+---------------+-----------------+--------------+-------------------+ | 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 | +-------------+------------------+-------------+---------------+------------------+--------------------+--------------+-------------+---------+------------------------------+----------------+----------------------+--------------------+------------------+--------------------------------+---------------------+---------------------------+-------------------------+-----------------------+-------------------+---------------------+----------------------------+-----------------+-------------------+-----------------+----------------+-----------------+----------------------+-------------------------+-----------------+----------------------+------------------------+----------------------------+--------------------------+------------------------+----------------+------------------+---------------+-----------------+--------------+-------------------+
Ahora, cuando nos desplazamos hacia los lados, podemos ver que el source_server , source_database , source_schema , source_table y source_column todas las columnas contienen valores.
En este caso, el procedimiento consulta tablas a través de un servidor vinculado llamado "Homer".
También notará que ahora se devuelven cuatro filas, en lugar de solo dos que se devolvieron cuando establecimos el tercer argumento en 0 . Las dos filas adicionales reflejan las columnas subyacentes que se consultan dentro del procedimiento almacenado.
Aquí está la definición del procedimiento almacenado:
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;Entonces, aunque el procedimiento devuelve solo dos columnas, necesita hacer referencia a otras columnas para completar su tarea.
Vea cómo sys.dm_exec_describe_first_result_set_for_object Funciona para más ejemplos.
El sys.dm_exec_describe_first_result_set Ver
Esta vista utiliza el mismo algoritmo que la vista anterior y devuelve la misma información. La diferencia es que analiza un lote de T-SQL, en lugar del procedimiento almacenado real.
Esto significa que puede usar esta vista para analizar el código que no está necesariamente en un procedimiento almacenado o desencadenador. Por ejemplo, puede usarlo para analizar una vista o una consulta ad hoc.
Pero este artículo trata sobre el análisis de procedimientos almacenados, así que aquí hay un ejemplo de cómo hacerlo.
SELECT *
FROM sys.dm_exec_describe_first_result_set(
'EXEC spAlbumsFromArtist @ArtistId = ''Iron Maiden''',
null,
1
);Resultado:
+-------------+------------------+-------------+---------------+------------------+--------------------+--------------+-------------+---------+------------------------------+----------------+----------------------+--------------------+------------------+--------------------------------+---------------------+---------------------------+-------------------------+-----------------------+-------------------+---------------------+----------------------------+-----------------+-------------------+-----------------+----------------+-----------------+----------------------+-------------------------+-----------------+----------------------+------------------------+----------------------------+--------------------------+------------------------+----------------+------------------+---------------+-----------------+--------------+-------------------+ | 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 | +-------------+------------------+-------------+---------------+------------------+--------------------+--------------+-------------+---------+------------------------------+----------------+----------------------+--------------------+------------------+--------------------------------+---------------------+---------------------------+-------------------------+-----------------------+-------------------+---------------------+----------------------------+-----------------+-------------------+-----------------+----------------+-----------------+----------------------+-------------------------+-----------------+----------------------+------------------------+----------------------------+--------------------------+------------------------+----------------+------------------+---------------+-----------------+--------------+-------------------+
Vea cómo sys.dm_exec_describe_first_result_set Funciona para más ejemplos.
El sp_describe_first_result_set Procedimiento almacenado del sistema
El sp_describe_first_result_set El procedimiento almacenado del sistema hace lo mismo (y usa el mismo algoritmo). Acepta un lote de T-SQL y devuelve los metadatos para su primer conjunto de resultados posible.
EXEC sp_describe_first_result_set
@tsql = N'EXEC spAlbumsFromArtist @ArtistId = ''Iron Maiden''',
@params = null,
@browse_information_mode = 1;Resultado:
+-------------+------------------+-------------+---------------+------------------+--------------------+--------------+-------------+---------+------------------------------+----------------+----------------------+--------------------+------------------+--------------------------------+---------------------+---------------------------+-------------------------+-----------------------+-------------------+---------------------+----------------------------+-----------------+-------------------+-----------------+----------------+-----------------+----------------------+-------------------------+-----------------+----------------------+------------------------+----------------------------+--------------------------+------------------------+---------------+--------------+--------------------+-------------------------+ | 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 | +-------------+------------------+-------------+---------------+------------------+--------------------+--------------+-------------+---------+------------------------------+----------------+----------------------+--------------------+------------------+--------------------------------+---------------------+---------------------------+-------------------------+-----------------------+-------------------+---------------------+----------------------------+-----------------+-------------------+-----------------+----------------+-----------------+----------------------+-------------------------+-----------------+----------------------+------------------------+----------------------------+--------------------------+------------------------+---------------+--------------+--------------------+-------------------------+
Vea cómo sp_describe_first_result_set Funciona para más ejemplos.
OPENROWSET con una Mesa Temporal
Otra opción es construir una consulta que coloque los resultados cero superiores de un OPENROWSET consulta en una tabla temporal, luego usa un procedimiento como sp_columns para devolver información de columna sobre esa tabla temporal (que contiene los datos de nuestro conjunto de resultados).
Por lo tanto, esto proporcionará detalles, como nombres de columnas, tipos de datos, etc.
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');Resultado:
+-------------------+---------------+----------------------------------------------------------------------------------------------------------------------------------+---------------+-------------+-------------+-------------+----------+---------+---------+------------+-----------+--------------+-----------------+--------------------+---------------------+--------------------+---------------+----------------+ | 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 | +-------------------+---------------+----------------------------------------------------------------------------------------------------------------------------------+---------------+-------------+-------------+-------------+----------+---------+---------+------------+-----------+--------------+-----------------+--------------------+---------------------+--------------------+---------------+----------------+
Con este método, también puede hacer cosas como intercambiar sp_columns para sp_help o similar.
