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Rails does not save concatataned string attributes

#6024

>> r = Role.first
=> #<Role role_id: 1, name: "bla", description: "bla">
>> str = (r.description << "oink")
=> "blaoink"
>> r.description = str
=> "blaoink"
>> r.save
=> true
>> r.reload
=> #<Role role_id: 1, name: "bla", description: "bla">

Notice how the "description" field doesn't change.
HOWEVER, this works:

>> r = Role.first
=> #<Role role_id: 1, name: "bla", description: "bla">
>> r.description = "#{r.description}oink"
=> "blaoink"
>> r.save
=> true
>> r.reload
=> #<Role role_id: 1, name: "bla", description: "blaoink">

this is just a simple activerecord object and "description" is just a simple text field. Rails 2.3.8. VERY weird...

Reported by suan · November 21st, 2010 @ 01:48 AM

Activity

Ravil Bayramgalin
- Tag set to invalid
ActiveRecord uses partial updates. It means that only changed (dirty) attributes will be updated. To keep track of dirty attributes ActiveRecord checks on assignment if new value is equal to old one if not attribute will be marked as dirty.

In your example,
```
str = (r.description << "oink")
```
you changed description attribute in place without assignment, so later on when you do make an assignment
```
r.description = str
```
description already equals str, so it's not marked as changed hence this attribute is not updated on save.

If you really need to use in place operation then you should mention it beforehand
```
r.description_will_change!
r.description << 'oink'
r.save # works as intended
```
November 21st, 2010 @ 04:10 AM
Rizwan Reza
- State changed from new to wontfix
- Importance changed from to Low
November 21st, 2010 @ 01:01 PM
Rizwan Reza
- Tag cleared.
November 21st, 2010 @ 01:01 PM