diff --git a/models.rb b/models.rb
new file mode 100644
index 0000000..3eb8d72
--- /dev/null
+++ b/models.rb
@@ -0,0 +1,30 @@
+require_relative "db"
+
+class Entity < Sequel::Model
+  one_to_many :notes
+  one_to_many :sources
+  one_to_one :title
+  many_to_many :tags
+  one_to_one :url
+end
+
+class Note < Sequel::Model
+  many_to_one :entity
+end
+
+class Source < Sequel::Model
+  many_to_one :entity
+  many_to_one :source, class: :Entity
+end
+
+class Title < Sequel::Model
+  many_to_one :entity
+end
+
+class Tag < Sequel::Model
+  many_to_many :entities
+end
+
+class Url < Sequel::Model
+  one_to_one :entity
+end