当约束被丢弃的明确DROP INDEX根本不准(An explicit DROP INDEX is

像丝毫不差暗示，我试图删除一个指标，但它不工作，消除约束时也是如此。使用的代码是以下几点：

OPEN cursor_drop_indexes 

FETCH next FROM cursor_drop_indexes INTO @Indexes_SchemaName, @Indexes_TableName, @Indexes_TableId, 
@Indexes_IndexName, @Indexes_IndexId, @Indexes_FileGroupName, @Indexes_FillFactor 

WHILE ( @@Fetch_Status = 0 ) 
  BEGIN 
      -- Used to remove UNIQUE KEY constraint enforcements
      IF @Indexes_IndexName NOT LIKE '%missing%' BEGIN
          SET @sql_index = ' ALTER TABLE [' + @Indexes_TableName + '] DROP CONSTRAINT [' 
                           + @Indexes_IndexName + ']'
          PRINT( @sql_index )
          EXEC sp_executesql @sql_index
      END
      -- Remove Index  
          SET @sql_index = ' DROP INDEX [' + @Indexes_IndexName + '] ON [' 
                           + @Indexes_SchemaName + '].[' + @Indexes_TableName + ']'

      PRINT( @sql_index )
      EXEC sp_executesql @sql_index

      FETCH next FROM cursor_drop_indexes INTO @Indexes_SchemaName, @Indexes_TableName, @Indexes_TableId
       , 
      @Indexes_IndexName, @Indexes_IndexId, @Indexes_FileGroupName, @Indexes_FillFactor 
  END 

CLOSE cursor_drop_indexes

和错误消息是：

ALTER TABLE [TB_CARTAO_CREDITO] DROP CONSTRAINT [IX_TB_CARTAO_CREDITO_UNIQUE] DROP INDEX [IX_TB_CARTAO_CREDITO_UNIQUE] ON [DBO]。[TB_CARTAO_CREDITO]消息3701，级别11，状态7,1行无法删除索引 'dbo.TB_CARTAO_CREDITO.IX_TB_CARTAO_CREDITO_UNIQUE'，因为它不存在，或者您没有权限。

谢谢并恭祝安康。

编辑：

所以，这些都是我的代码作出后哈姆雷特Hakobyan帮我明显的变化

IF (SELECT is_unique FROM SYS.indexes WHERE name = @Indexes_IndexName ) = 1 BEGIN
    SET @sql_index = ' ALTER TABLE [' + @Indexes_TableName + '] DROP CONSTRAINT [' 
                 + @Indexes_IndexName + ']'
END
ELSE
-- Remove Index  
SET @sql_index = ' DROP INDEX [' + @Indexes_IndexName + '] ON [' 
                 + @Indexes_SchemaName + '].[' + @Indexes_TableName + ']'

PRINT( @sql_index )
EXEC sp_executesql @sql_index

错误信息是非常明确的。当你删除约束相应的对象（即指数）也将被删除。