大规模创造和危害性关联

Question

I have 3 models (Genre, Mood, Tempo) each with a has_and_belongs_to_many association with another model (Track). The user can upload an Excel file with info for each track and I want to be able to create the respective records and add the association all at once in my update method.

I'm reading each row from the spreadsheet and creating arrays holding the genres, moods, and tempos that are to be associated with each track, but I'm not sure how to correctly create the association.

Something like:

1.upto @worksheet.last_row_index do |index|
  row = @worksheet.row(index)
  genres = row[6].split(", ")
  genres.each do |g|
    Genre.find_or_create_by_name(g) // not sure what to do here exactly
  end
end

The Track ID is row[0].

I need to create each Genre if it doesn't exist, and associate that track with each. If the genre does exist, then I just need to create the association. Same for moods and tempos.

Thanks for any assistance.

Answer 1

This seems to do it.

1.upto @worksheet.last_row_index do |index|
  row = @worksheet.row(index)
  track = Track.find(row[0])
  genres = row[6].split(", ")
  genres.each do |g|
    track.genres << Genre.find_or_create_by_name(g)
  end
end