# Validate uniqueness of two fields

**URL:** <https://www.ruby-forum.com/t/validate-uniqueness-of-two-fields/53950>\
**Category:** Rails\
**Created:** [February 18, 2006, 12:04am UTC](https://www.ruby-forum.com/t/validate-uniqueness-of-two-fields/53950 "2006-02-18T00:04:35Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![glenatron](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/94ad74/32.png) [@glenatron](https://www.ruby-forum.com/u/glenatron)\
**Post date:** [February 18, 2006, 12:04am UTC](https://www.ruby-forum.com/t/validate-uniqueness-of-two-fields/53950/1 "2006-02-18T00:04:35Z")

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I have Proposals and Members and Members can vote for a proposal only  
once.

So, I have “Vote belongs\_to :member, :proposal”, but to make sure a  
member only votes  
once, I want to make sure that there isn’t a vote in the db with that  
member\_id and  
proposal\_id. I can just put the appropriate find in a vote.valid? but I  
wanted to make  
sure I wasn’t missing a nice rails shortcut.

In other words, can I do something with “validates\_uniqueness\_of” to  
make it consider a  
pair of columns, member\_id and proposal\_id?

thanks,

b

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<div class="post-metadata">

**Author:** ![glenatron](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/94ad74/32.png) [@glenatron](https://www.ruby-forum.com/u/glenatron)\
**Post date:** [February 18, 2006, 12:16am UTC](https://www.ruby-forum.com/t/validate-uniqueness-of-two-fields/53950/2 "2006-02-18T00:16:38Z")

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You can by using trunk version of rails. Otherwise write your own  
validate method.

## – Kent

> **[DATANOISE.COM](https://www.datanoise.com/)**
>
> DATANOISE.COM - Contact us for any business inquiries

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<div class="post-metadata">

**Author:** ![glenatron](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/94ad74/32.png) [@glenatron](https://www.ruby-forum.com/u/glenatron)\
**Post date:** [February 18, 2006, 12:55am UTC](https://www.ruby-forum.com/t/validate-uniqueness-of-two-fields/53950/3 "2006-02-18T00:55:59Z")

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thanks…