# Migrations-looping through add\_column lines

**URL:** <https://www.ruby-forum.com/t/migrations-looping-through-add-column-lines/109271>\
**Category:** Rails\
**Created:** [July 12, 2007, 11:32pm UTC](https://www.ruby-forum.com/t/migrations-looping-through-add-column-lines/109271 "2007-07-12T23:32:48Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![dkanders](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/7bcc69/32.png) [@dkanders](https://www.ruby-forum.com/u/dkanders)\
**Post date:** [July 12, 2007, 11:32pm UTC](https://www.ruby-forum.com/t/migrations-looping-through-add-column-lines/109271/1 "2007-07-12T23:32:48Z")

</div>

Hi All,

Hoping this is an easy question… Can I loop through add\_columns?

I’ve got a bunch of columns that I need to add to a table… I don’t  
really want to type “add\_column” 30 times… and then “remove\_column”  
another 30 times

Is there an easy way to just loop through the is so my migration doesn’t  
look like this?:

def self.up

```
add_column :enrollments, :fname
add_column :enrollments, :lname
add_column :enrollments, :email, :string
add_column :enrollments, :school_type, :string
add_column :enrollments, :number_of_students, :string

add_column :enrollments, :school_name, :string
add_column :enrollments, :internet, :boolean
add_column :enrollments, :internet_quality, :string
#(and on and on and on.....)

```

end

def self.down

```
remove_column :enrollments, :fname
remove_column :enrollments, :lname
remove_column :enrollments, :email
remove_column :enrollments, :school_type
remove_column :enrollments, :number_of_students

remove_column :enrollments, :school_name
remove_column :enrollments, :internet
remove_column :enrollments, :internet_quality
#blah blah blah...

```

end

Thanks!

---

<div class="post-metadata">

**Author:** ![dkanders](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/7bcc69/32.png) [@dkanders](https://www.ruby-forum.com/u/dkanders)\
**Post date:** [July 12, 2007, 11:50pm UTC](https://www.ruby-forum.com/t/migrations-looping-through-add-column-lines/109271/2 "2007-07-12T23:50:27Z")

</div>

sure you could do that, but the problem is that most likely your  
columns are going to have more differences than just the name of the  
column, so you’d have to structure your loops around you individual  
columns…when its all said and done, it would most likely have just  
been easier to spell each one out. not only that, but the method that  
everyone tends to use is very readable.

ex:

# all same type, easy enough

[:name, :description, :location].each do |col|  
add\_column col, :string  
end

now try that when all your columns are different types, lengths, not  
null, unique, have default values, etc…not so easy now.