# Data Constraint

**URL:** <https://www.ruby-forum.com/t/data-constraint/89410>\
**Category:** Rails\
**Created:** [March 20, 2007, 8:38am UTC](https://www.ruby-forum.com/t/data-constraint/89410 "2007-03-20T08:38:50Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![hasana](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/h/d78d45/32.png) [@hasana](https://www.ruby-forum.com/u/hasana)\
**Post date:** [March 20, 2007, 8:38am UTC](https://www.ruby-forum.com/t/data-constraint/89410/1 "2007-03-20T08:38:50Z")

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How to set the constraint of the input by the user…??

Example…

If user input the name field with number.Error message will be display…

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**Author:** ![hasana](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/h/d78d45/32.png) [@hasana](https://www.ruby-forum.com/u/hasana)\
**Post date:** [March 20, 2007, 8:53am UTC](https://www.ruby-forum.com/t/data-constraint/89410/2 "2007-03-20T08:53:33Z")

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Google for “rails validates\_format\_of example”.

Preston

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**Author:** ![hasana](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/h/d78d45/32.png) [@hasana](https://www.ruby-forum.com/u/hasana)\
**Post date:** [March 20, 2007, 2:38pm UTC](https://www.ruby-forum.com/t/data-constraint/89410/3 "2007-03-20T14:38:18Z")

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Hasana H. wrote:

> How to set the constraint of the input by the user…??
> 
> Example…
> 
> If user input the name field with number.Error message will be display…

In your model use the validate\_format\_of, use Google to know more about  
it 🙂