Rails如何更新所有记录的列为零的记录？

Question

I want to set udtraekkes (datetime) to NULL for all those records where udtraekkesinfo is NOT equal NULL or NIL. My model name is Konkurrencer.

How do I update alle the konkurrencers records in the rails console?

Answer 1

I think you need update_all method. Documentation

Answer 2

In Rails 4.0.13, I tested with this syntax might it would do same for you in rails 3.

Model.where(conditions).update_all(:column_name=> nil)
where conditions are filtered condition to fetch the each record and update_all will operate on those record, you can update one or more column based on your requirement. 

for your requirement code would be.

Konkurrencer.where(:udtraekkes=> nil).update_all(:udtraekkes=> nil)

Answer 3

Konkurrencer.update_all（{udtraekkes：nil}，“udtraekkesinfo IS NOT NULL”）