sql-server - 在 SQL Server View 中查找计算列

Question

一位同事让我帮助他们识别具有一个或多个计算列的数据库中的 View 。该数据库有数百个 View ，因此他们试图找到一种自动化的方式来完成这项任务。我没有在数据库中看到我期望的结果。下面是一个例子:

--DROP TABLE dbo.Products

CREATE TABLE dbo.Products   
(  
    ProductID int IDENTITY (1,1) NOT NULL  
  , QtyAvailable smallint  
  , UnitPrice money   
);  

--DROP VIEW dbo.uvw_Products
CREATE VIEW dbo.uvw_Products
AS
    SELECT    ProductID
            , QtyAvailable
            , UnitPrice
            , (QtyAvailable * UnitPrice) AS InventoryValue
    FROM      dbo.Products;

-- Look at the view and find the computed column
SELECT OBJECT_SCHEMA_NAME(T.[object_id],DB_ID()) AS [Schema],   
        T.[name] AS [table_name], AC.[name] AS [column_name],   
        TY.[name] AS system_data_type, AC.[max_length],  
        AC.[precision], AC.[scale], AC.[is_nullable], AC.[is_ansi_padded], AC.[is_computed]
FROM sys.[views] AS T   
  INNER JOIN sys.[all_columns] AC ON T.[object_id] = AC.[object_id]  
 INNER JOIN sys.[types] TY ON AC.[system_type_id] = TY.[system_type_id] AND AC.[user_type_id] = TY.[user_type_id]  
WHERE T.[is_ms_shipped] = 0
AND T.[name] = 'uvw_Products'
ORDER BY T.[name], AC.[column_id]


-- Pulls up no results - no entries in sys.computed_columns
SELECT TOP 10 * 
FROM sys.computed_columns C
INNER JOIN sys.views V ON C.[object_id] = V.[object_id]
WHERE V.[name] = 'uvw_Products'

从这个简单的示例中可以看出，SQL Server 似乎没有将值存储在 is_computed 列中。

我错过了什么？我们如何在 View 中找到计算列？

Answer 1

我知道这并不理想，我不认为存在针对此问题的万无一失的解决方案，但是根据您的命名约定，您可以对列名的表 sys View 进行连接，以便查看哪些列存在和不存在在那里。

例如:

SELECT v.*
FROM 
(
    SELECT  [Schema]        = OBJECT_SCHEMA_NAME(t.[object_id], DB_ID())
          , [table_name]    = t.[name] 
          , [column_name]   = vc.[name]
    FROM sys.[views] t  
    JOIN sys.[all_columns] vc ON t.[object_id] = vc.[object_id]
) v
LEFT JOIN 
(
    SELECT  [Schema]        = OBJECT_SCHEMA_NAME(t.[object_id], DB_ID())
          , [table_name]    = t.[name] 
          , [column_name]   = vc.[name]
    FROM sys.[tables] t  
    JOIN sys.[all_columns] vc ON t.[object_id] = vc.[object_id]
) t
    ON t.[column_name] = v.[column_name]
WHERE t.[table_name] IS NULL

返回:

Schema | table_name    | column_name
----------------------------------------
dbo    | uvw_Products  | InventoryValue

如果您的 View 在其名称中包含源表，如“uvw_Products”，您也可以在连接中使用它以避免其他表中的列妨碍。

再次它并不理想，而是缩小搜索范围的相对简单的解决方案