sql - TSQL 伪随机文本生成器

Question

我正在对 SQL sproc 进行一些性能测试，只是想推出一个快速数据生成器进行测试。

我正在寻找一种简单的方法来生成伪随机(在这种情况下不需要真正的随机)varchar 字段。

到目前为止，我的想法是有一个可以使用的有效字符的字符定义，然后根据这个定义构建字符串，并使用伪随机长度来定义最大/最小长度的长度变化。

编辑:

我的测试数据生成器:

DECLARE @MyDataTable TABLE
(
  RecID int IDENTITY(1,1) PRIMARY KEY,
  SomeText varchar(255)
)

DECLARE @RecId int, @SomeText varchar(255),
        @maxlength int, @minlength int, 
        @RecordCount int, @Counter int
SET @maxlength = 254
SET @minlength = 50
SET @RecordCount = 500000
SET @Counter = 1

WHILE (@Counter < @RecordCount)
BEGIN
 INSERT INTO @MyDataTable
 (
  SomeText
 )
 SELECT  TOP 1
 ( 
   select top (abs(checksum(newid())) % (@maxlength-@minlength) + @minlength) char(abs(checksum(newid())) % 26 + ascii('A'))  
   from sys.all_objects a1
   where sign(a1.object_id) = sign(t.object_id) /* Meaningless thing to force correlation */
   for xml path('')
 ) as NewRandomString 
 FROM sys.all_objects t;
 SET @Counter = @Counter + 1
END

Answer 1

我最近写了一篇关于这个的博客文章。

http://msmvps.com/blogs/robfarley/archive/2009/12/07/randomising-data.aspx

select top (@stringlength) char(abs(checksum(newid())) % 26 + ascii('A')) 
from sys.all_objects 
for xml path('')
;

编辑:对不起 - 没有包括随机长度的东西......

SELECT 
(
  select top (abs(checksum(newid())) % (@maxlength-@minlength) + @minlength) char(abs(checksum(newid())) % 26 + ascii('A')) 
  from sys.all_objects 
  for xml path('')
) as NewRandomString
FROM yourTable; /* Maybe something like dbo.nums? */

编辑:对不起 - 需要相关...

SELECT  
( 
  select top (abs(checksum(newid())) % (@maxlength-@minlength) + @minlength) char(abs(checksum(newid())) % 26 + ascii('A'))  
  from sys.all_objects a1
  where sign(a1.object_id) = sign(t.object_id) /* Meaningless thing to force correlation */
  for xml path('')
) as NewRandomString 
,*
FROM sys.all_objects t;