将列添加到特定表

Question

我有多个表，例如大约 2000 个表，其中少数表是启用了 change_tracking 的表。我只需要向那些 change_tracking_enabled 表添加额外的列。

我的代码正在向所有 2000 个表添加列。我只需要为 CHANGE_TRACKING_ENABLED 表添加列。请帮帮我

1. 这是我显示 change_tracking_enabled 表的代码。

   USE Test
   GO
   SELECT s.name as Schema_name, t.name AS Table_name, tr.*
   FROM sys.change_tracking_tables tr
   INNER JOIN sys.tables t on t.object_id = tr.object_id
   INNER JOIN sys.schemas s on s.schema_id = t.schema_id
   

2. 这是我将列添加到所有 2000 个表的代码。

   USE TestDB
   GO
   --Declare Variables
   DECLARE @TableName VARCHAR(100)
   DECLARE @TableSchema VARCHAR(100)
   DECLARE @COLUMN_NAME VARCHAR(50)
   SET @COLUMN_NAME='ddtm' -- Change Column Name according to your requirement
   DECLARE @COLUMN_DATATYPE VARCHAR(50)
   SET @COLUMN_DATATYPE='DateTime' -- Provide data type for column
   
   --Declare Cursor
   DECLARE CUR CURSOR FOR
     SELECT TABLE_SCHEMA,
            TABLE_NAME
     FROM   INFORMATION_SCHEMA.TABLES
     WHERE  TABLE_TYPE = 'BASE TABLE'
   --OPEN CURSOR
   OPEN CUR
   --Fetch First Row
   FETCH NEXT FROM CUR INTO @TableSchema,@TableName
   --Loop
   WHILE @@FETCH_STATUS = 0
     BEGIN
   
     DECLARE @SQL NVARCHAR(MAX)
     SET @SQL=NULL
     IF NOT EXISTS ( SELECT 1 FROM INFORMATION_SCHEMA.COLUMNS 
          WHERE TABLE_NAME=@TableName AND COLUMN_NAME=@COLUMN_NAME 
   and Table_Schema=@TableSchema)
     BEGIN
     SET @SQL='ALTER TABLE '+@TableSchema+'.'+@TableName +' ADD '+@COLUMN_NAME
                            + ' '+@COLUMN_DATATYPE
       PRINT @SQL
       EXEC ( @SQL)
     END
   
     IF EXISTS ( SELECT 1 FROM INFORMATION_SCHEMA.COLUMNS 
                 WHERE TABLE_NAME=@TableName AND COLUMN_NAME=@COLUMN_NAME 
   and Table_Schema=@TableSchema)
     BEGIN
     PRINT 'Column Already exists in Table'
     END
         FETCH NEXT FROM CUR INTO @TableSchema,@TableName
     END
   --Close and Deallocate Cursor
   CLOSE CUR
   DEALLOCATE CUR
   

Answer 1

查询

  SELECT TABLE_SCHEMA,
         TABLE_NAME
  FROM   INFORMATION_SCHEMA.TABLES
  WHERE  TABLE_TYPE = 'BASE TABLE'

和

SELECT s.name as Schema_name, t.name AS Table_name, tr.*
FROM sys.change_tracking_tables tr
INNER JOIN sys.tables t on t.object_id = tr.object_id
INNER JOIN sys.schemas s on s.schema_id = t.schema_id

不是否相同，当然您会得到不同的结果...使用您在第 1 步中使用的查询（减去 tr.*）作为步骤2中的查询；因为这会为您提供具有 CDC 的表。