How do I loop through all record and update a field from a lookup into a multi pick list?

Question

The user decided the 'Program' field should allow multiple programs. So I created a new field that uses multi pick list. So now I want to loop through and copy the field 'ABC' to the multi pick list option 'ABC'

Do I need to code this or is there a tool?

More Clearly:

There is a book object with a NAME and a GENRE (Action/Horror/Comedy). People have used this for a few months.

One day they realize they want the book object to have MANY genres. A new field is created called GENRES (it is a multi pick list of the collection (Action/Horror/Comedy)to hold these... So now a book can be a Action AND a Comedy.

The problem is. There is already 5000 records that use the old GENRE field.

How do I copy that GENRE field to the new GENRES field for all the records?

does that make sense ?

Answer 1

Follow these steps:

• Open the Dataloader and select the object and export the all the data in .csv format.

• Now, go to dataloader again, select the update button, then select the same object, when it will ask for field mapping between .csv and SFDC fields,

  • remove the previous SFDC field name GENRE from the mapping.
  • select new field GENRES of SFDC and map with the .csv field GENRE.

Basically, replacing the column names the of the mapping. And finally upload the data.

Refer: Dataloader youtube video for guidance

Answer 2

If I understand correctly and it is a picklist to multi-picklist value copy you need to do, I would use the Developer Console's Execute Anonymous.

The code you would need to execute would be:

Book__c[] books = [select Id, Genre__c from Book__c where Genres__c = null];
for (Book__c book : books) {
    book.Genres__c = book.Genre__c;
}
update books;

Multi-select picklist use a semi-colon as a separator but you don't need to worry about that here as you are only copying in a single value.

If there were a lot more records so that governor limits were hit, you could add say limit 5000 to the query and execute the code multiple times.