Use rowid for virtual tables

README.md

@@ -307,14 +307,12 @@ class AddEmbeddingToItems < ActiveRecord::Migration[7.2]
     # Rails < 8
     execute <<~SQL
       CREATE VIRTUAL TABLE items USING vec0(
-        id integer PRIMARY KEY AUTOINCREMENT NOT NULL,
         embedding float[3] distance_metric=L2
       )
     SQL
 
     # Rails 8+
     create_virtual_table :items, :vec0, [
-      "id integer PRIMARY KEY AUTOINCREMENT NOT NULL",
       "embedding float[3] distance_metric=L2"
     ]
   end
@@ -323,6 +321,16 @@ end
 
 Use `distance_metric=cosine` for cosine distance
 
+Create a model with `rowid` as the primary key
+
+```ruby
+class Item < ApplicationRecord
+  self.primary_key = "rowid"
+
+  has_neighbors :embedding, dimensions: 3
+end
+```
+
 Get the nearest neighbors
 
 ```ruby

test/sqlite_virtual_test.rb

@@ -22,6 +22,8 @@ def test_euclidean
     create_items(SqliteVecItem, :embedding)
 
     relation = SqliteVecItem.where("embedding MATCH ?", [1, 1, 1].to_s).order(:distance).limit(3)
+    assert_equal [1, 3, 2], relation.all.map(&:id)
+    assert_equal [1, 3, 2], relation.pluck(:rowid)
     assert_elements_in_delta [0, 1, Math.sqrt(3)], relation.pluck(:distance)
     assert_match "SCAN vec_items VIRTUAL TABLE INDEX", relation.explain.inspect
 

test/support/sqlite.rb

@@ -15,27 +15,23 @@ class SqliteRecord < ActiveRecord::Base
 
   if ActiveRecord::VERSION::MAJOR >= 8
     create_virtual_table :vec_items, :vec0, [
-      "id integer PRIMARY KEY AUTOINCREMENT NOT NULL",
       "embedding float[3] distance_metric=L2"
     ]
   else
     execute <<~SQL
       CREATE VIRTUAL TABLE vec_items USING vec0(
-        id integer PRIMARY KEY AUTOINCREMENT NOT NULL,
         embedding float[3] distance_metric=L2
       )
     SQL
   end
 
   if ActiveRecord::VERSION::MAJOR >= 8
     create_virtual_table :cosine_items, :vec0, [
-      "id integer PRIMARY KEY AUTOINCREMENT NOT NULL",
       "embedding float[3] distance_metric=cosine"
     ]
   else
     execute <<~SQL
       CREATE VIRTUAL TABLE cosine_items USING vec0(
-        id integer PRIMARY KEY AUTOINCREMENT NOT NULL,
         embedding float[3] distance_metric=cosine
       )
     SQL
@@ -51,11 +47,13 @@ class SqliteItem < SqliteRecord
 
 class SqliteVecItem < SqliteRecord
   has_neighbors :embedding, dimensions: 3
+  self.primary_key = "rowid"
   self.table_name = "vec_items"
 end
 
 class SqliteCosineItem < SqliteRecord
   has_neighbors :embedding, dimensions: 3
+  self.primary_key = "rowid"
   self.table_name = "cosine_items"
 end