# About query database and virtual attributes

**URL:** <https://www.ruby-forum.com/t/about-query-database-and-virtual-attributes/126671>\
**Category:** Rails\
**Created:** [January 21, 2008, 9:52am UTC](https://www.ruby-forum.com/t/about-query-database-and-virtual-attributes/126671 "2008-01-21T09:52:05Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![flyingzumwalt](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/f/74df32/32.png) [@flyingzumwalt](https://www.ruby-forum.com/u/flyingzumwalt)\
**Post date:** [January 21, 2008, 9:52am UTC](https://www.ruby-forum.com/t/about-query-database-and-virtual-attributes/126671/1 "2008-01-21T09:52:05Z")

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Hi,

My model has a lot of virtual attributes. So when I use  
find(:all, :condition=\>blablabla),  
can I use virtual attribute directly?

eg. in my model:  
def mydatetime  
self.date+self.time  
end  
can i just use “mydatetime=xxx” to match the records in db?

of course, my model is far more complicated than this.

Any idea?

---

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**Author:** ![flyingzumwalt](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/f/74df32/32.png) [@flyingzumwalt](https://www.ruby-forum.com/u/flyingzumwalt)\
**Post date:** [January 21, 2008, 10:24am UTC](https://www.ruby-forum.com/t/about-query-database-and-virtual-attributes/126671/2 "2008-01-21T10:24:57Z")

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you would need to define mydatetime

def mydatetime=(datetime)  
date = datetime.some\_modifier  
time = datetime.some\_modifier  
end

---

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**Author:** ![flyingzumwalt](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/f/74df32/32.png) [@flyingzumwalt](https://www.ruby-forum.com/u/flyingzumwalt)\
**Post date:** [January 22, 2008, 3:32am UTC](https://www.ruby-forum.com/t/about-query-database-and-virtual-attributes/126671/3 "2008-01-22T03:32:53Z")

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Keynan P. wrote:

> you would need to define mydatetime
> 
> def mydatetime=(datetime)  
> date = datetime.some\_modifier  
> time = datetime.some\_modifier  
> end

Unfortunately, it doesn’t solve the problem.

Error messege:  
Mysql::Error: Unknown column ‘who\_chunk2’ in ‘where clause’: SELECT \*  
FROM `skus` WHERE (who\_chunk2=‘Matt’)

My code is like:

def who\_chunk2  
if !self.who\_chunk.blank?  
if b=User.find\_by\_id(self.who\_chunk)  
b.name  
end  
end  
end  
def who\_chunk2=(st)  
if !st.blank?  
self.who\_chunk=User.find\_by\_name(st).id  
end  
end

---

<div class="post-metadata">

**Author:** ![flyingzumwalt](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/f/74df32/32.png) [@flyingzumwalt](https://www.ruby-forum.com/u/flyingzumwalt)\
**Post date:** [December 14, 2008, 4:21pm UTC](https://www.ruby-forum.com/t/about-query-database-and-virtual-attributes/126671/4 "2008-12-14T16:21:22Z")

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Any update on this? I am also facing the same issue?

Please help!

On Jan 22, 7:32 am, Matt Z. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)