Question

So I’m having some trouble with DataMapper and object associations. (Code provided at bottom). I’m getting errors upon saving to the extent that some id’s are not set, which I think has something to do with how I setup my associations/not fully understanding how associations work under DataMapper.

The code I’m running is:

Rose.setup_datamapper
Rose::User.first_or_create(:username => 'some-user', :password => 'REDACTED')

Rose::User.all.each do |user|
   user.scrape_and_update
   user.errors.each { |e| puts e } unless user.save
   user.bandwidth_entries.each { |e| puts e }
end

And the errors I am recieving are:

 ~ (0.000064) SELECT "id", "username", "password" FROM "rose_users" WHERE ("username" = 'some-user' AND "password" = 'REDACTED') ORDER BY "id" LIMIT 1
 ~ (0.000042) SELECT "id", "username", "password" FROM "rose_users" ORDER BY "id"
 ~ rose_bandwidth_entries.device_network_address may not be NULL (code: 19, sql state: , query: INSERT INTO "rose_bandwidth_entries" ("policy_mbytes_received", "policy_mbytes_sent", "actual_mbytes_received", "actual_mbytes_sent", "timestamp", "bandwidth_class", "user_id") VALUES (583.34, 39.58, 590.27, 44.26,  '2011-09-20T13:39:31-04:00', 0.0, 1), uri: sqlite3:/Users/axiixc/Dropbox/Ruby/stats.sqlite?port=&adapter=sqlite3&fragment=&path=/Users/axiixc/Dropbox/Ruby/stats.sqlite&scheme=sqlite3&host=&user=&password=&query=)

Model classes are here: http://www.pastie.org/private/xer5grfaulmnxalne6g5va (link for brevity)

EDIT Okay the crash is coming from create on line 26:

# /Library/Ruby/Gems/1.8/gems/dm-do-adapter-1.1.0/lib/dm-do-adapter/adapter.rb:114:in `execute_non_query': rose_bandwidth_entries.device_network_address may not be NULL (DataObjects::IntegrityError)

main_entry = BandwidthMainEntry.create(
    :user => self,
    :timestamp => Time.new,
    :policy_mbytes_received => scrape_dict[:main][:policy_mbytes_received],
    :policy_mbytes_sent => scrape_dict[:main][:policy_mbytes_sent],
    :actual_mbytes_received => scrape_dict[:main][:actual_mbytes_received],
    :actual_mbytes_sent => scrape_dict[:main][:actual_mbytes_sent],
    :bandwidth_class => scrape_dict[:main][:bandwidth_class]
 )

So would it have something to do with the inheritance from BandwidthEntry/BandwidthDeviceEntry, because that class doesn’t even have an association with a device.

Might as well post the full stack trace too: http://www.pastie.org/private/ospnkeeylul9mhf4fgxhdq

EDIT Okay, here is basically the rest of the code http://www.pastie.org/private/pwmihpa6vu3h7lypx64ag

I can never tell how much to post, sorry!

Answer 1

Okay, so I derped on inheritance, and should have read more of the documentation. What was happening was I missed the property :type, Discriminator needed when using subclasses. So even though my one subclass didn’t need a device associated with it, the other did, so that’s what was triggering the error.

My working model looks like this: http://www.pastie.org/2564668