Neo4j-查询结果随机顺序

Question

I'm not exactly sure what's gone on inside my app but my queries don't seem to give me my results in order of creation. It recently rearranged itself without me changing the code related to the query. However, I've obviously done SOMETHING.

At one point I was trying to get my rails c results writen into a file. However, that was simply writing the output of the query to the file. I didn't think that would effect query orders...

The queries were simply like

File.open('text.txt', 'w') do |f|
   User.all.each do |u|
      f.puts u.email
   end
end

I think I can re-sort one of my relationships by adding property :created_at and sorting it by that timestamp.

But there is no way for me to do this with my Q+A association as they aren't activerel right now.

It's called like this

<% @event.event_questions.each do |q| %>

In the app there were 3 questions created. The order that it ended up showing was

2,1,3

How does the neo4j query determine the order of the objects? What could I have possibly done wrong?

Answer 1

I don't think that neo4j has any way of determining the date/time of when nodes are created. It stores an internal, incrementally generated numeric ID, but those IDs can be recycled when you restart your server. It could be that order changed after you restarted your server. I'm not sure if neo4j returns nodes in any sort of order by default. I'm assuming it doesn't guarantee order unless you specify an ORDER BY

For the ordering of relationships without ActiveRel , you can do:

@event.event_questions(:question, :rel).order('rel.created_at')