How to dummy mass update via Apex Data Loader?

Question

I built a trigger on Object 1 which has a field, field1 which when updated will calculate another field, field2 in same object (had to use trigger for it's complexity).

Now my question is that field1 is already available in the object, for which I have to perform update in order to fill up field2 field. So how do I prepare the csv file for the dummy update?

Is my following way the right?

1. First download csv containing the record ids and with field1.
2. Update with same file with data loader.

Thanks in advance.

Answer 1

It looks like your trigger doesn't check to see if field1 has changed, only that it is set. This means that all you need to do is run some anonymous apex to get the trigger to fire. You don't even need to change any fields on the records. If you execute the code below it will cause your trigger to fire:

update [select id from Object1 where field1 != null and field2 = null];

If your trigger is not bulkified then you may hit some limits. If you do you can fire the trigger on less records in a single transaction until you get them all updated. See the code below which will only update 1000 records.

update [select id from Object1 where field1 != null and field2 = null limit:1000];