在SQL Server的表格列中使用UDF作为默认值 [英] Use a UDF as the default value in a table column in SQL Server

问题描述

我在SQL Server 2012 Express中创建了一个缩放器UDF（称为sCurrentAppUser（）），我想在定义表时将此UDF用作默认值。但是每次尝试时，我都会收到'sCurrentAppUser'不是公认的内置函数名称的错误。

I created a scaler UDF (called sCurrentAppUser()) in SQL Server 2012 Express and I would like to use this UDF as a default value when defining a table. But every time I try, I get an error of "'sCurrentAppUser' is not a recognized built-in function name."

因为我不能发布两个以上的函数链接（信誉），我将在评论中链接到我的研究和参考。

Since I can't post more than two links yet (reputation), I'll link to my research and references in a comment.

这是我的UDF：

ALTER FUNCTION [dbo].[sCurrentAppUser] ()
RETURNS nVarChar(128)
AS BEGIN
   DECLARE @CurrentAppUser nVarChar(128)

   IF EXISTS (SELECT 1 FROM ActiveConnections WHERE ComputerName = host_name ()) BEGIN
      SELECT   @CurrentAppUser = CONVERT (nVarChar(128), LoginUser)
      FROM     ActiveConnections
      WHERE    ComputerName = host_name ()

   END ELSE BEGIN
      SELECT   @CurrentAppUser = Convert (nVarChar(128), suser_sname ())
      WHERE    NOT EXISTS (
                  SELECT   1
                  FROM     ActiveConnections
                  WHERE    ComputerName = host_name ()
               )

   END

   RETURN @CurrentAppUser

END

而我尝试在第一列上使用默认约束创建表：

And my attempt at creating the table with the default constraint on the first column:

CREATE TABLE [dbo].[Clients](
   [ModifyingUser] [nvarchar](128) NOT NULL DEFAULT sCurrentAppUser (),
   [Modification] [char](1) NULL DEFAULT 'A',
   [ModifyingHost] [nvarchar](128) NOT NULL DEFAULT host_name (),
   [ClientID] [uniqueidentifier] NOT NULL,
   [Label] [nvarchar](1024) NULL,
   CONSTRAINT [PK_Clients] PRIMARY KEY (
      [ClientID] ASC
   )
)

推荐答案

您应该为该函数添加架构名称：

You should add schema name for that function:

CREATE TABLE [dbo].[Clients](
   [ModifyingUser] [nvarchar](128) NOT NULL DEFAULT dbo.sCurrentAppUser (),
   [Modification] [char](1) NULL DEFAULT 'A',
   [ModifyingHost] [nvarchar](128) NOT NULL DEFAULT host_name (),
   [ClientID] [uniqueidentifier] NOT NULL,
   [Label] [nvarchar](1024) NULL,
   CONSTRAINT [PK_Clients] PRIMARY KEY (
      [ClientID] ASC
   )
)

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