# Delete Duplicates

**URL:** <https://www.ruby-forum.com/t/delete-duplicates/140137>\
**Category:** Ruby\
**Created:** [June 11, 2008, 8:39am UTC](https://www.ruby-forum.com/t/delete-duplicates/140137 "2008-06-11T08:39:38Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![tornado](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/43a26b/32.png) [@tornado](https://www.ruby-forum.com/u/tornado)\
**Post date:** [June 11, 2008, 8:39am UTC](https://www.ruby-forum.com/t/delete-duplicates/140137/1 "2008-06-11T08:39:38Z")

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Hello Sir/Madam,  
I want to know how can i delete duplicates entries from  
database using rake task.

Regards,

Amit K.

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**Author:** ![tornado](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/43a26b/32.png) [@tornado](https://www.ruby-forum.com/u/tornado)\
**Post date:** [June 11, 2008, 2:50pm UTC](https://www.ruby-forum.com/t/delete-duplicates/140137/2 "2008-06-11T14:50:11Z")

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Amit K. wrote:

> ```
> I want to know how can i delete duplicates entries from
> 
> ```
> 
> database using rake task.

I am not sure if you are asking to learn about rake tasks or database  
cleanup. Assuming that the result is what matters, I suggest that you  
apply a primary index to the fields you are checking. That will remove  
duplicates automatically.

hth

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<div class="post-metadata">

**Author:** ![tornado](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/43a26b/32.png) [@tornado](https://www.ruby-forum.com/u/tornado)\
**Post date:** [June 11, 2008, 2:07pm UTC](https://www.ruby-forum.com/t/delete-duplicates/140137/3 "2008-06-11T14:07:02Z")

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I don’t know of any built-in task that already does that. Thus, you’ll  
have to:

- Figure out how to detect duplicates in your data.
- Write some code to detect and delete the duplicates.
- Write a rake task to call the code that you wrote in the previous  
step.
- Run the rake task.

Good luck,  
Craig

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**Author:** ![tornado](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/43a26b/32.png) [@tornado](https://www.ruby-forum.com/u/tornado)\
**Post date:** [June 12, 2008, 7:16am UTC](https://www.ruby-forum.com/t/delete-duplicates/140137/4 "2008-06-12T07:16:05Z")

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Thankyou for your advice…if possible can u suggest me how to detect n  
delete duplicates…