如何在visual basic access 2007中对memo数据类型应用distinct [英] How to apply distinct on memo datatype in visual basic access 2007

问题描述

你好，



我正在使用Visual Basic access 2007创建一个Tool.Now我卡住了，因为我必须在Memo数据类型上应用distinct。但是我收到错误



该字段太小，无法接受您尝试添加访问2010备忘录字段的数据量。请尝试插入或粘贴较少的数据< br $>






请帮我解决这个问题。



谢谢，

Naveen



我的尝试：



我尝试了下面提到的查询来从备忘录字段中获取不同的记录。



从table1中选择不同的CAS。

Hello,

I am using the Visual basic access 2007 to create a Tool.Now my getting stuck as I have to apply distinct on Memo data type.But I am getting the error

"the field is too small to accept the amount of data you attempted to add access 2010 memo fields.Try inserting or pasting less data"



Please help me to out from this problem.

Thanks,
Naveen

What I have tried:

I have tried the below mentioned query to get the distinct records from memo field.

select distinct CAS from table1.

推荐答案

简短的回答是你不能。



但是，你可以计算一个哈希值在该字段上，将其存储在另一个（非备忘录）列中，然后您可以使用

The short answer is that you can't.

However, you could calculate a hash value on the field, store that in another (non-memo) column then you can use

select distinct CASasHash from Table1

以识别您想要的记录。



没有内置函数来计算哈希值，但是如果你谷歌有几个可用的例子......实际上我试图找到你的参考时遇到的第一个就是这个...... UtterAccess论坛>索引备注字段 [ ^ ]



It确实提出了为什么要这样做的问题 - 你可能想重新考虑你的数据模型。

to identify the records you want.

There are no in-built functions to calculate the hash, but there are several examples available if you google... in fact the first one I came across when trying to find you a reference was this ... UtterAccess Forums >"indexing" Memo Fields[^]

It does beg the question as to why you would want to do this - you may like to rethink your data model.

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