Sql 挑出EVENTDATA的特定部分以在DDL触发器中使用？

当前触发器如下所示：

CREATE TRIGGER TestTrigger
ON DATABASE
FOR ALTER_TABLE
AS
BEGIN
SET NOCOUNT ON;
    DECLARE @FULL_STATEMENT SYSNAME
    SELECT @FULL_STATEMENT = EVENTDATA().value('(/EVENT_INSTANCE/TSQLCommand/CommandText)[1]','nvarchar(max)')
    print('The following SQL statement was executed:')
    print('')
    print (@FULL_STATEMENT)
    print('')
    print('Next step is to work out how to single out the added column name')
    ROLLBACK
END

然后运行以下SQL语句：

USE [a_Database]
ALTER TABLE dbo.TABLE
ADD TestColumn varchar(50)

它输出以下内容：

已执行以下SQL语句：

altertable dbo.TABLE

添加TestColumn varchar（50）

下一步是找出如何挑出添加的列名

Msg 3609，16级，状态2，第2行

事务在触发器中结束。批处理已中止

最终目标是挑出“TestColumn”，以确保它不包含可能破坏内部程序的特定字符。例如，“TestColumn”将是一个有效的名称，但“Test.Column”将不是

---

选择它并将其传递给新变量（“ColumnName”）以检查不需要的字符的最佳方法是什么？

您需要记住，alter语句可以添加多个列。如果查看为alter column语句生成的XML，您会更好地了解：

ALTER TABLE dbo.EventTest ADD NewColumn1 INT, NewColumn2 INT;

----------------------------
<EVENT_INSTANCE>
  <EventType>ALTER_TABLE</EventType>
  <PostTime>2015-06-30T14:28:30.790</PostTime>
  <SPID>67</SPID>
  <ServerName>XXXXXX</ServerName>
  <LoginName>XXXXXX</LoginName>
  <UserName>dbo</UserName>
  <DatabaseName>XXXXXX</DatabaseName>
  <SchemaName>dbo</SchemaName>
  <ObjectName>EventTest</ObjectName>
  <ObjectType>TABLE</ObjectType>
  <AlterTableActionList>
    <Create>
      <Columns>
        <Name>NewColumn1</Name>
        <Name>NewColumn2</Name>
      </Columns>
    </Create>
  </AlterTableActionList>
  <TSQLCommand>
    <SetOptions ANSI_NULLS="ON" ANSI_NULL_DEFAULT="ON" ANSI_PADDING="ON" QUOTED_IDENTIFIER="ON" ENCRYPTED="FALSE" />
    <CommandText>ALTER TABLE dbo.EventTest ADD NewColumn1 INT, NewColumn1 INT;</CommandText>
  </TSQLCommand>
</EVENT_INSTANCE>

然后，您可以简单地使用

EXISTS

检查保留名称列表等，并检查不需要的字符：

IF EXISTS
(   SELECT  1
    FROM    (   SELECT  ColumnName = Cols.value('.', 'SYSNAME')
                FROM    EVENTDATA().nodes('EVENT_INSTANCE/AlterTableActionList/Create/Columns') x (Cols)
            ) AS t
    WHERE   PATINDEX('%[.@!-]%', t.ColumnName) > 0  -- USE PATTERN MATCH TO CHECK FOR UNWANTED CHARACTERS
    OR      EXISTS 
            (   SELECT  1
                FROM    dbo.ReservedColumnNames AS rc
                WHERE   rc.Name = t.ColumnName
            )
)
BEGIN
    RAISERROR(...)
    ROLLBACK;
END

另一个要考虑的是，<代码> SPReNeNe>代码>将触发一个不同的事件，并且您可能也想跟踪这个。这里的XML看起来像：

<EVENT_INSTANCE>
  <EventType>RENAME</EventType>
    ....
  <SchemaName>dbo</SchemaName>
  <ObjectName>NewColumn</ObjectName>
  <ObjectType>COLUMN</ObjectType>
  <TargetObjectName>EventTest</TargetObjectName>
  <TargetObjectType>TABLE</TargetObjectType>
  <NewObjectName>NewColumn2</NewObjectName>
  <Parameters>
    <Param>dbo.EventTest.NewColumn</Param>
    <Param>NewColumn2</Param>
    <Param>COLUMN</Param>
  </Parameters>
  <TSQLCommand>
    <SetOptions ANSI_NULLS="ON" ANSI_NULL_DEFAULT="ON" ANSI_PADDING="ON" QUOTED_IDENTIFIER="ON" ENCRYPTED="FALSE" />
    <CommandText>EXECUTE SP_RENAME 'dbo.EventTest.NewColumn', 'NewColumn2', 'COLUMN';</CommandText>
  </TSQLCommand>
</EVENT_INSTANCE>

---

谢谢！现在将尝试执行此操作：）和。。。这似乎奏效了。谢谢，省去了我一个半小时的头痛！

<EVENT_INSTANCE>
  <EventType>RENAME</EventType>
    ....
  <SchemaName>dbo</SchemaName>
  <ObjectName>NewColumn</ObjectName>
  <ObjectType>COLUMN</ObjectType>
  <TargetObjectName>EventTest</TargetObjectName>
  <TargetObjectType>TABLE</TargetObjectType>
  <NewObjectName>NewColumn2</NewObjectName>
  <Parameters>
    <Param>dbo.EventTest.NewColumn</Param>
    <Param>NewColumn2</Param>
    <Param>COLUMN</Param>
  </Parameters>
  <TSQLCommand>
    <SetOptions ANSI_NULLS="ON" ANSI_NULL_DEFAULT="ON" ANSI_PADDING="ON" QUOTED_IDENTIFIER="ON" ENCRYPTED="FALSE" />
    <CommandText>EXECUTE SP_RENAME 'dbo.EventTest.NewColumn', 'NewColumn2', 'COLUMN';</CommandText>
  </TSQLCommand>
</EVENT_INSTANCE>

SELECT  EVENTDATA().value('EVENT_INSTANCE[1]/NewObjectName[1]', 'SYSNAME')
WHERE   EVENTDATA().value('EVENT_INSTANCE[1]/EventType[1]', 'VARCHAR(13)') = 'RENAME'
AND     EVENTDATA().value('EVENT_INSTANCE[1]/ObjectType[1]', 'VARCHAR(13)') = 'COLUMN';