# ActiveRecord: find\_or\_create with has\_and\_belongs\_to\_many --

**URL:** <https://www.ruby-forum.com/t/activerecord-find-or-create-with-has-and-belongs-to-many/102826>\
**Category:** Rails\
**Created:** [August 2, 2006, 7:58am UTC](https://www.ruby-forum.com/t/activerecord-find-or-create-with-has-and-belongs-to-many/102826 "2006-08-02T07:58:51Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Red\_Daly](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/e0b2c6/32.png) [@Red\_Daly](https://www.ruby-forum.com/u/Red_Daly)\
**Post date:** [August 2, 2006, 7:58am UTC](https://www.ruby-forum.com/t/activerecord-find-or-create-with-has-and-belongs-to-many/102826/1 "2006-08-02T07:58:51Z")

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I am attempting to use find\_or\_create on a foreign table with a  
has\_and\_belongs\_to\_many relationship with my current table. I am doing  
the following:

term = school.terms.find\_or\_create\_by\_code(“FALL06”)

the queries in the log show the expected SELECT statement to query if  
there is a join table record between the school and term with code  
“FALL06”:

SELECT \* FROM term  
INNER JOIN school\_term ON term.id = school\_term.term\_id  
WHERE (school\_term.school\_id = 1 )  
AND (term.`code` = ‘FALL06’ )  
LIMIT 1

but the INSERT behavior does not include a join table insert if the  
SELECT does not find an appropriate record:

INSERT INTO term (`code`, `name_full`, `name_common`, `date_end`,  
`date_start`)  
VALUES(‘FALL06’, NULL, NULL, NULL, NULL)

I have resolved this by changing my original code to implement a  
uniqueness check in ruby:

term = school.terms.find\_or\_create\_by\_code(“FALL06”)  
school.terms \<\< term unless school.terms.any? do |i| i == term;

It seems like ActiveRecord and SQL should take care of that behavior  
rather than the ActiveRecord implementor and Ruby. Am I missing  
something? Is there another way to do what I want?

Also, I’m not sure if c.l.ruby is the best newsgroup, but I couldn’t  
find a ruby on rails group.

Thanks Sincerely,  
Red Daly

---

<div class="post-metadata">

**Author:** ![Red\_Daly](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/e0b2c6/32.png) [@Red\_Daly](https://www.ruby-forum.com/u/Red_Daly)\
**Post date:** [October 16, 2007, 10:33pm UTC](https://www.ruby-forum.com/t/activerecord-find-or-create-with-has-and-belongs-to-many/102826/2 "2007-10-16T22:33:48Z")

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I’ve recently used this form:

school.terms \<\< Term.find\_or\_create\_by\_code(“FALL06”)