created_at field sometimes becomes nil

Question

I think created_at is always set to the time a record created in by ActiveRecord, but I found some records are created with null created_at. Are there any condition to cause this?

Answer 1

These columns created_at, updated_at, created_on, updated_on are automatically handled for you by rails.

However, there are a few notes:

1. Do not change the attr's value (i.e. created_at should be nil before create and shouldn't be changed before update). Otherwise, ActiveRecord won't update attr's value with the current time.
2. Check that your <ClassName>.record_timestamps is set to true.

Also, I'd suggest to you to add not-null constraint to these columns:

change_column :<table_name>, :created_at, :datetime, :null => false

This way you will be sure that this column always have a not-null value.

Answer 2

Are you using attr_accessible or attr_protected on your model?

Because without those basic protections, any update request could be setting these otherwise unvalidated & unprotected attributes.

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