Experiments with the GratefuldDeadConcterts database

First modify the database-entry (development) in /config/connect.yml to «GreatfulDeadConerts». This should be present after the installation of the database Then execute « ./bin/active-orient-console d »

Present Classes (Hierarchy) 
  ---
  - - E
  - - followed_by
  - sung_by
  - written_by
  - V

  Active Classes  ->  ActiveOrient ClassName
  ---------------------------------------------
  V ->  V
  E ->  E
  followed_by ->  FollowedBy
  sung_by ->  SungBy
  written_by ->  WrittenBy
  ---------------------------------------------

Lets start with simple queries

• Select all vertices (or object) in the database

V.all

• Select the vertex with the id #9:8

V.autoload_object '#9:8'

• Select all the artists

V.where type: 'artist'

• Select all the songs that have been performed 10 times

Display songnames and authors

song_10 = V.where type: 'song', performances:  10
song_10.name
=> ["TOMORROW IS FOREVER", "SHE BELONGS TO ME", "UNBROKEN CHAIN"]
song_10.out_written_by.in.name 
=> [["Dolly_Parton"], ["Bob_Dylan"], ["Petersen"]]

• Select all the songs that have been performed more or less 10 times

V.where "type = 'song’ and performances > 10"
V.where "type = 'song’ and performances < 10"

• Count all songs and artists

V.count where: { type: 'song' }
V.count where: { type: 'song', performances:  10 }

V.count where: { type: 'artist' }

• Find all songs sung by the first artist

First get the artist

 first_artist = OrientSupport::OrientQuery.new from: artist_vertex, where: { type: 'artist'} , limit: 1
 first_artist.to_s => "select  from V where type = 'artist'  limit 1"

Traverse through the database. List any song and author that is sung by this artist

songs = DB.execute{ "select expand(set(in('sung_by'))) from (#{first_artist.to_s}) " }
songs.name
==> ["ROSA LEE MCFALL", "ROW JIMMY", "THAT WOULD BE SOMETHING", "BETTY AND DUPREE", "WHISKEY IN THE JAR", ...]

authors = DB.execute{ "select expand(set(in('sung_by').out('written_by'))) from (#{first_artist.to_s}) " }
authors.name
==>  ["Bob_Dylan", "Chuck_Berry", "Unknown", "Bernie_Casey_Pinkard", ...]