remove me

Gemfile.lock

@@ -21,12 +21,18 @@ GEM
     ast (2.4.2)
     coderay (1.1.3)
     concurrent-ruby (1.2.2)
+    debug (1.8.0)
+      irb (>= 1.5.0)
+      reline (>= 0.3.1)
     diff-lcs (1.5.0)
     docile (1.4.0)
     faker (3.2.0)
       i18n (>= 1.8.11, < 2)
     i18n (1.14.1)
       concurrent-ruby (~> 1.0)
+    io-console (0.6.0)
+    irb (1.7.4)
+      reline (>= 0.3.6)
     json (2.6.3)
     language_server-protocol (3.17.0.3)
     lint_roller (1.1.0)
@@ -45,6 +51,8 @@ GEM
     rainbow (3.1.1)
     rake (13.0.6)
     regexp_parser (2.8.1)
+    reline (0.3.7)
+      io-console (~> 0.5)
     rexml (3.2.5)
     rspec (3.12.0)
       rspec-core (~> 3.12.0)
@@ -112,6 +120,7 @@ PLATFORMS
   x86_64-linux
 
 DEPENDENCIES
+  debug (>= 1.0.0)
   faker (~> 3.2)
   mysql2 (~> 0.5.5)
   pg (~> 1.5)

bin/setup

@@ -9,19 +9,9 @@ set -vx
 # PostgreSQL
 if [ -x "$(command -v psql)" ]; then
   echo "PostgreSQL is installed"
-  psql -h localhost -p 5432 -W postgres -c 'create database random_rails_test;' -U postgres;
-else
-  echo "PostgreSQL is not installed"
-  # check it is mac or linux
-  if [ "$(uname)" == "Darwin" ]; then
-    brew install postgresql
-  elif [ "$(expr substr $(uname -s) 1 5)" == "Linux" ]; then
-    sudo apt-get install postgresql postgresql-contrib
-  fi
-
-  # create psql user
-  sudo -u postgres createuser -s $(whoami)
   psql -h localhost -p 5432 -W postgres -c 'create database random_rails_test;' -U $(whoami);
+else
+  echo "PostgreSQL is not installed!"
 
   exit 1
 fi
@@ -31,19 +21,12 @@ if [ -x "$(command -v mysql)" ]; then
   echo "MySQL is installed"
   mysql -h localhost -P 3306 -u root -e 'create database random_rails_test;'
 else
-  echo "MySQL is not installed"
-  # check it is mac or linux
-  if [ "$(uname)" == "Darwin" ]; then
-    brew install gcc zstd openssl mysql
-  elif [ "$(expr substr $(uname -s) 1 5)" == "Linux" ]; then
-    sudo apt-get install mysql-server mysql-client libmysqlclient-dev
-  fi
-
-  # create mysql user
-  mysql -h localhost -P 3306 -u root -e 'create database random_rails_test;'
+  echo "MySQL is not installed!"
 
   exit 1
 fi
 
+# add sqlite
+
 bundle install
 DB=pg bundle exec rspec

lib/random-rails/adapters/active_record/base.rb

@@ -1,12 +1,36 @@
+require "active_record"
+require "debug"
 module RandomRails
   module Adapters
     module ActiveRecord
       module Base
         def random(precision: 10)
           # TODO: use different ways to sample data depending on the database adapter
-          from("#{table_name} TABLESAMPLE BERNOULLI(#{precision})").limit(1)
+          if connection.adapter_name == "postgresql"
+            from("#{table_name} TABLESAMPLE BERNOULLI(#{precision})").limit(1)
+          else
+            # from("\"#{table_name}\" LIMIT 1 OFFSET (SELECT CAST(ROUND(RANDOM() * (SELECT COUNT(*) FROM \"#{table_name}\"))) AS INTEGER)")
+            # =================
+            # offset_value = connection.select_value("SELECT RANDOM() % MAX(id) FROM \"people\"").abs
+
+            # offset(offset_value).limit(1)
+            # =================
+            # binding.irb
+            from("\"#{table_name}\" LIMIT 1 OFFSET abs(random() % (SELECT count(*) FROM \"#{table_name}\"))")
+
+            # SELECT "people".* FROM "people" LIMIT 1 OFFSET abs(random()%(SELECT count(*) FROM "people"));
+
+            # from("\"#{table_name}\" OFFSET (SELECT CAST(ROUND(RANDOM() * (SELECT COUNT(*) FROM \"#{table_name}\")) AS INTEGER))")
+            # people limit 1 offset (SELECT CAST(ROUND(RANDOM() * (SELECT COUNT(*) FROM "people")) AS INTEGER))
+          end
         end
       end
     end
   end
 end
+
+# select * from people limit 1 offset (SELECT CAST(ROUND(RANDOM() * (SELECT COUNT(*) FROM "people")) AS INTEGER))
+
+
+
+# SELECT ROUND(RANDOM() * (SELECT COUNT(*) FROM users)) FROM users LIMIT 1

random-rails.gemspec

@@ -42,6 +42,7 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency "rubocop-performance", "~> 1.18"
   spec.add_development_dependency "simplecov", "~> 0.22.0"
   spec.add_development_dependency "pry", "~> 0.14.2"
+  spec.add_development_dependency "debug", ">= 1.0.0"
   spec.add_development_dependency "sqlite3", "~> 1.6"
   spec.add_development_dependency "pg", "~> 1.5"
   spec.add_development_dependency "mysql2", "~> 0.5.5"

spec/lib/random/adapters/active_record/base_spec.rb

@@ -1,17 +1,56 @@
 # frozen_string_literal: true
-
+require "pry"
 RSpec.describe RandomRails::Adapters::ActiveRecord::Base do
   describe "#random" do
     it { expect(Person).to respond_to(:random) }
     it { expect(Person.random).to be_a(ActiveRecord::Relation) }
-    it { expect(Person.random.to_sql).to include("TABLESAMPLE BERNOULLI") }
+
+    case ActiveRecord::Base.connection.adapter_name
+    when "PostgreSQL"
+      it { expect(Person.random.to_sql).to include("TABLESAMPLE BERNOULLI") }
+    when "SQLite"
+      it { expect(Person.random.to_sql).to include("OFFSET") }
+    end
 
     context "when precision is specified" do
-      it { expect(Person.random(precision: 5).to_sql).to include("TABLESAMPLE BERNOULLI(5)") }
+      case ActiveRecord::Base.connection.adapter_name
+      when "PostgreSQL"
+        it { expect(Person.random(precision: 5).to_sql).to include("TABLESAMPLE BERNOULLI(5)") }
+      when "SQLite"
+        it { expect(Person.random(precision: 5).to_sql).to include("OFFSET") }
+      end
+
+      # the main poblem is that calling `Person.random.inspect` will execute the query with "LIMIT ?" at the end that raises a syntax error
+      it { binding.irb; expect(Person.random.inspect).to include(ActiveRecord::Relation.to_s) }
     end
 
     context "when limit is specified" do
       it { expect(Person.random.limit(5).to_sql).to include("LIMIT 5") }
     end
   end
 end
+
+
+# Person.from("
+#   users
+#   OFFSET ROUND(
+#     RAND() * (
+#       SELECT COUNT(*) FROM users
+#     )
+#   )
+# ").limit(1).inspect
+
+
+# offset = "SELECT ROUND(RAND() * (SELECT COUNT(*) FROM users))"
+
+# "SELECT * FROM users OFFSET #{offset}"
+
+
+# # * Correct offset
+# # ROUND(RANDOM() * (SELECT COUNT(*) FROM people))
+
+# offset = "ROUND(RANDOM() * (SELECT COUNT(*) FROM people))"
+
+# sql = "SELECT * FROM people OFFSET #{offset}"
+
+# Person.from("people OFFSET #{offset}")

spec/support/schema.rb

@@ -24,7 +24,8 @@
   # Otherwise, assume SQLite3: `bundle exec rake spec`
   ActiveRecord::Base.establish_connection(
     adapter: "sqlite3",
-    database: ":memory:"
+    # database: ":memory:"
+    database: "random_rails_test.sqlite3"
   )
 end