diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 2baea8b..4367266 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -34,6 +34,68 @@ jobs:
       - name: Run tests
         run: bundle exec rspec
 
+  test_db:
+    runs-on: ubuntu-latest
+    name: test (${{ matrix.appraisal }}, ${{ matrix.database }})
+
+    strategy:
+      fail-fast: false
+      matrix:
+        ruby: ["4.0"]
+        appraisal: ["rails_8.1"]
+        database: ["postgresql", "mysql2"]
+
+    services:
+      postgres:
+        image: postgres:16
+        env:
+          POSTGRES_USER: postgres
+          POSTGRES_PASSWORD: postgres
+        ports:
+          - 5432:5432
+        options: >-
+          --health-cmd pg_isready
+          --health-interval 10s
+          --health-timeout 5s
+          --health-retries 5
+      mysql:
+        image: mysql:8
+        env:
+          MYSQL_ROOT_PASSWORD: root
+        ports:
+          - 3306:3306
+        options: >-
+          --health-cmd "mysqladmin ping -h localhost"
+          --health-interval 10s
+          --health-timeout 5s
+          --health-retries 5
+
+    env:
+      BUNDLE_GEMFILE: gemfiles/${{ matrix.appraisal }}.gemfile
+      FIXTURE_KIT_INTEGRATION_FRAMEWORK: rspec
+      FIXTURE_KIT_DB: ${{ matrix.database }}
+      FIXTURE_KIT_DB_HOST: ${{ matrix.database == 'mysql2' && '127.0.0.1' || 'localhost' }}
+      FIXTURE_KIT_DB_USERNAME: ${{ matrix.database == 'mysql2' && 'root' || 'postgres' }}
+      FIXTURE_KIT_DB_PASSWORD: ${{ matrix.database == 'mysql2' && 'root' || 'postgres' }}
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Ruby ${{ matrix.ruby }}
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ${{ matrix.ruby }}
+          bundler-cache: true
+
+      - name: Install dummy app dependencies
+        working-directory: spec/dummy
+        env:
+          BUNDLE_GEMFILE: ""
+        run: bundle install
+
+      - name: Run tests
+        run: bundle exec rspec
+
   lint:
     runs-on: ubuntu-latest
 
diff --git a/Appraisals b/Appraisals
index 0067581..e07b3fb 100644
--- a/Appraisals
+++ b/Appraisals
@@ -2,10 +2,26 @@ appraise "rails-8.0" do
   gem "activesupport", "~> 8.0.0"
   gem "activerecord", "~> 8.0.0"
   gem "railties", "~> 8.0.0"
+
+  group :postgres do
+    gem "pg"
+  end
+
+  group :mysql do
+    gem "mysql2"
+  end
 end
 
 appraise "rails-8.1" do
   gem "activesupport", "~> 8.1.0"
   gem "activerecord", "~> 8.1.0"
   gem "railties", "~> 8.1.0"
+
+  group :postgres do
+    gem "pg"
+  end
+
+  group :mysql do
+    gem "mysql2"
+  end
 end
diff --git a/Gemfile b/Gemfile
index be173b2..87f6250 100644
--- a/Gemfile
+++ b/Gemfile
@@ -3,3 +3,11 @@
 source "https://rubygems.org"
 
 gemspec
+
+group :postgres do
+  gem "pg"
+end
+
+group :mysql do
+  gem "mysql2"
+end
diff --git a/gemfiles/rails_8.0.gemfile b/gemfiles/rails_8.0.gemfile
index 621a692..40fd720 100644
--- a/gemfiles/rails_8.0.gemfile
+++ b/gemfiles/rails_8.0.gemfile
@@ -6,4 +6,12 @@ gem "activesupport", "~> 8.0.0"
 gem "activerecord", "~> 8.0.0"
 gem "railties", "~> 8.0.0"
 
+group :postgres do
+  gem "pg"
+end
+
+group :mysql do
+  gem "mysql2"
+end
+
 gemspec path: "../"
diff --git a/gemfiles/rails_8.0.gemfile.lock b/gemfiles/rails_8.0.gemfile.lock
index 1d5f4a1..b4c26a4 100644
--- a/gemfiles/rails_8.0.gemfile.lock
+++ b/gemfiles/rails_8.0.gemfile.lock
@@ -74,6 +74,8 @@ GEM
       nokogiri (>= 1.12.0)
     minitest (6.0.1)
       prism (~> 1.5)
+    mysql2 (0.5.7)
+      bigdecimal
     nokogiri (1.19.1-aarch64-linux-gnu)
       racc (~> 1.4)
     nokogiri (1.19.1-aarch64-linux-musl)
@@ -90,6 +92,13 @@ GEM
       racc (~> 1.4)
     nokogiri (1.19.1-x86_64-linux-musl)
       racc (~> 1.4)
+    pg (1.6.3)
+    pg (1.6.3-aarch64-linux)
+    pg (1.6.3-aarch64-linux-musl)
+    pg (1.6.3-arm64-darwin)
+    pg (1.6.3-x86_64-darwin)
+    pg (1.6.3-x86_64-linux)
+    pg (1.6.3-x86_64-linux-musl)
     pp (0.6.3)
       prettyprint
     prettyprint (0.2.0)
@@ -181,6 +190,8 @@ DEPENDENCIES
   appraisal
   fixture_kit!
   irb
+  mysql2
+  pg
   railties (~> 8.0.0)
   rake
   rspec-rails
@@ -212,6 +223,7 @@ CHECKSUMS
   logger (1.7.0) sha256=196edec7cc44b66cfb40f9755ce11b392f21f7967696af15d274dde7edff0203
   loofah (2.25.0) sha256=df5ed7ac3bac6a4ec802df3877ee5cc86d027299f8952e6243b3dac446b060e6
   minitest (6.0.1) sha256=7854c74f48e2e975969062833adc4013f249a4b212f5e7b9d5c040bf838d54bb
+  mysql2 (0.5.7) sha256=ba09ede515a0ae8a7192040a1b778c0fb0f025fa5877e9be895cd325fa5e9d7b
   nokogiri (1.19.1-aarch64-linux-gnu) sha256=cfdb0eafd9a554a88f12ebcc688d2b9005f9fce42b00b970e3dc199587b27f32
   nokogiri (1.19.1-aarch64-linux-musl) sha256=1e2150ab43c3b373aba76cd1190af7b9e92103564063e48c474f7600923620b5
   nokogiri (1.19.1-arm-linux-gnu) sha256=0a39ed59abe3bf279fab9dd4c6db6fe8af01af0608f6e1f08b8ffa4e5d407fa3
@@ -220,6 +232,13 @@ CHECKSUMS
   nokogiri (1.19.1-x86_64-darwin) sha256=7093896778cc03efb74b85f915a775862730e887f2e58d6921e3fa3d981e68bf
   nokogiri (1.19.1-x86_64-linux-gnu) sha256=1a4902842a186b4f901078e692d12257678e6133858d0566152fe29cdb98456a
   nokogiri (1.19.1-x86_64-linux-musl) sha256=4267f38ad4fc7e52a2e7ee28ed494e8f9d8eb4f4b3320901d55981c7b995fc23
+  pg (1.6.3) sha256=1388d0563e13d2758c1089e35e973a3249e955c659592d10e5b77c468f628a99
+  pg (1.6.3-aarch64-linux) sha256=0698ad563e02383c27510b76bf7d4cd2de19cd1d16a5013f375dd473e4be72ea
+  pg (1.6.3-aarch64-linux-musl) sha256=06a75f4ea04b05140146f2a10550b8e0d9f006a79cdaf8b5b130cde40e3ecc2c
+  pg (1.6.3-arm64-darwin) sha256=7240330b572e6355d7c75a7de535edb5dfcbd6295d9c7777df4d9dddfb8c0e5f
+  pg (1.6.3-x86_64-darwin) sha256=ee2e04a17c0627225054ffeb43e31a95be9d7e93abda2737ea3ce4a62f2729d6
+  pg (1.6.3-x86_64-linux) sha256=5d9e188c8f7a0295d162b7b88a768d8452a899977d44f3274d1946d67920ae8d
+  pg (1.6.3-x86_64-linux-musl) sha256=9c9c90d98c72f78eb04c0f55e9618fe55d1512128e411035fe229ff427864009
   pp (0.6.3) sha256=2951d514450b93ccfeb1df7d021cae0da16e0a7f95ee1e2273719669d0ab9df6
   prettyprint (0.2.0) sha256=2bc9e15581a94742064a3cc8b0fb9d45aae3d03a1baa6ef80922627a0766f193
   prism (1.9.0) sha256=7b530c6a9f92c24300014919c9dcbc055bf4cdf51ec30aed099b06cd6674ef85
diff --git a/gemfiles/rails_8.1.gemfile b/gemfiles/rails_8.1.gemfile
index b394a09..4cb9159 100644
--- a/gemfiles/rails_8.1.gemfile
+++ b/gemfiles/rails_8.1.gemfile
@@ -6,4 +6,12 @@ gem "activesupport", "~> 8.1.0"
 gem "activerecord", "~> 8.1.0"
 gem "railties", "~> 8.1.0"
 
+group :postgres do
+  gem "pg"
+end
+
+group :mysql do
+  gem "mysql2"
+end
+
 gemspec path: "../"
diff --git a/gemfiles/rails_8.1.gemfile.lock b/gemfiles/rails_8.1.gemfile.lock
index d6d959c..5b684f2 100644
--- a/gemfiles/rails_8.1.gemfile.lock
+++ b/gemfiles/rails_8.1.gemfile.lock
@@ -75,6 +75,8 @@ GEM
       nokogiri (>= 1.12.0)
     minitest (6.0.1)
       prism (~> 1.5)
+    mysql2 (0.5.7)
+      bigdecimal
     nokogiri (1.19.1-aarch64-linux-gnu)
       racc (~> 1.4)
     nokogiri (1.19.1-aarch64-linux-musl)
@@ -91,6 +93,13 @@ GEM
       racc (~> 1.4)
     nokogiri (1.19.1-x86_64-linux-musl)
       racc (~> 1.4)
+    pg (1.6.3)
+    pg (1.6.3-aarch64-linux)
+    pg (1.6.3-aarch64-linux-musl)
+    pg (1.6.3-arm64-darwin)
+    pg (1.6.3-x86_64-darwin)
+    pg (1.6.3-x86_64-linux)
+    pg (1.6.3-x86_64-linux-musl)
     pp (0.6.3)
       prettyprint
     prettyprint (0.2.0)
@@ -182,6 +191,8 @@ DEPENDENCIES
   appraisal
   fixture_kit!
   irb
+  mysql2
+  pg
   railties (~> 8.1.0)
   rake
   rspec-rails
@@ -214,6 +225,7 @@ CHECKSUMS
   logger (1.7.0) sha256=196edec7cc44b66cfb40f9755ce11b392f21f7967696af15d274dde7edff0203
   loofah (2.25.0) sha256=df5ed7ac3bac6a4ec802df3877ee5cc86d027299f8952e6243b3dac446b060e6
   minitest (6.0.1) sha256=7854c74f48e2e975969062833adc4013f249a4b212f5e7b9d5c040bf838d54bb
+  mysql2 (0.5.7) sha256=ba09ede515a0ae8a7192040a1b778c0fb0f025fa5877e9be895cd325fa5e9d7b
   nokogiri (1.19.1-aarch64-linux-gnu) sha256=cfdb0eafd9a554a88f12ebcc688d2b9005f9fce42b00b970e3dc199587b27f32
   nokogiri (1.19.1-aarch64-linux-musl) sha256=1e2150ab43c3b373aba76cd1190af7b9e92103564063e48c474f7600923620b5
   nokogiri (1.19.1-arm-linux-gnu) sha256=0a39ed59abe3bf279fab9dd4c6db6fe8af01af0608f6e1f08b8ffa4e5d407fa3
@@ -222,6 +234,13 @@ CHECKSUMS
   nokogiri (1.19.1-x86_64-darwin) sha256=7093896778cc03efb74b85f915a775862730e887f2e58d6921e3fa3d981e68bf
   nokogiri (1.19.1-x86_64-linux-gnu) sha256=1a4902842a186b4f901078e692d12257678e6133858d0566152fe29cdb98456a
   nokogiri (1.19.1-x86_64-linux-musl) sha256=4267f38ad4fc7e52a2e7ee28ed494e8f9d8eb4f4b3320901d55981c7b995fc23
+  pg (1.6.3) sha256=1388d0563e13d2758c1089e35e973a3249e955c659592d10e5b77c468f628a99
+  pg (1.6.3-aarch64-linux) sha256=0698ad563e02383c27510b76bf7d4cd2de19cd1d16a5013f375dd473e4be72ea
+  pg (1.6.3-aarch64-linux-musl) sha256=06a75f4ea04b05140146f2a10550b8e0d9f006a79cdaf8b5b130cde40e3ecc2c
+  pg (1.6.3-arm64-darwin) sha256=7240330b572e6355d7c75a7de535edb5dfcbd6295d9c7777df4d9dddfb8c0e5f
+  pg (1.6.3-x86_64-darwin) sha256=ee2e04a17c0627225054ffeb43e31a95be9d7e93abda2737ea3ce4a62f2729d6
+  pg (1.6.3-x86_64-linux) sha256=5d9e188c8f7a0295d162b7b88a768d8452a899977d44f3274d1946d67920ae8d
+  pg (1.6.3-x86_64-linux-musl) sha256=9c9c90d98c72f78eb04c0f55e9618fe55d1512128e411035fe229ff427864009
   pp (0.6.3) sha256=2951d514450b93ccfeb1df7d021cae0da16e0a7f95ee1e2273719669d0ab9df6
   prettyprint (0.2.0) sha256=2bc9e15581a94742064a3cc8b0fb9d45aae3d03a1baa6ef80922627a0766f193
   prism (1.9.0) sha256=7b530c6a9f92c24300014919c9dcbc055bf4cdf51ec30aed099b06cd6674ef85
diff --git a/lib/fixture_kit/coders/active_record_coder.rb b/lib/fixture_kit/coders/active_record_coder.rb
index d06e7f8..f1ee5d0 100644
--- a/lib/fixture_kit/coders/active_record_coder.rb
+++ b/lib/fixture_kit/coders/active_record_coder.rb
@@ -15,7 +15,10 @@ def generate(parent_data: nil, &block)
         model_name = name[NAME_PATTERN, :model_name]
         next unless model_name
 
-        captured_models.add(ActiveSupport::Inflector.constantize(model_name))
+        klass = ActiveSupport::Inflector.safe_constantize(model_name)
+        next unless klass.is_a?(Class) && klass < ActiveRecord::Base
+
+        captured_models.add(klass)
       end
 
       ActiveSupport::Notifications.subscribed(subscriber, EVENT, monotonic: true, &block)
@@ -27,11 +30,25 @@ def generate(parent_data: nil, &block)
     end
 
     def mount(data)
-      statements_by_connection(data).each do |connection, statements|
-        connection.disable_referential_integrity do
-          # execute_batch is private in current supported Rails versions.
-          # This should be revisited when Rails 8.2 makes it public.
-          connection.__send__(:execute_batch, statements, "FixtureKit Load")
+      models_by_pool(data).each do |pool, models|
+        pool.with_connection do |connection|
+          statements = models.flat_map do |model|
+            [build_delete_sql(connection, model.table_name), data[model]].compact
+          end
+
+          connection.disable_referential_integrity do
+            # execute_batch is private in current supported Rails versions.
+            # This should be revisited when Rails 8.2 makes it public.
+            connection.__send__(:execute_batch, statements, "FixtureKit Insert")
+          end
+
+          verify_foreign_keys!(connection)
+
+          # Replayed INSERTs use explicit PKs, which Postgres sequences do not
+          # observe. Re-sync the sequence so subsequent Model.create calls don't
+          # collide with an id we just inserted. No-op on adapters whose PK
+          # generators advance from explicit-id INSERTs (MySQL, SQLite).
+          reset_primary_key_sequences(connection, models.map(&:table_name))
         end
       end
     end
@@ -51,24 +68,30 @@ def base_table_model(model)
 
     def generate_statements(models)
       models.each_with_object({}) do |model, statements|
-        columns = model.column_names
+        columns = insertable_columns(model)
+        column_names = columns.map(&:name)
 
         rows = []
         model.unscoped.order(:id).find_each do |record|
-          row_values = columns.map do |col|
+          row_values = column_names.map do |col|
             value = record.read_attribute_before_type_cast(col)
             model.connection.quote(value)
           end
           rows << "(#{row_values.join(", ")})"
         end
 
-        sql = rows.empty? ? nil : build_insert_sql(model.table_name, columns, rows, model.connection)
+        sql = rows.empty? ? nil : build_insert_sql(model.table_name, column_names, rows, model.connection)
         statements[model] = sql
       end
     end
 
-    def build_delete_sql(model)
-      "DELETE FROM #{model.quoted_table_name}"
+    def insertable_columns(model)
+      supports_virtual = model.connection.supports_virtual_columns?
+      model.columns.reject { |c| supports_virtual && c.virtual? }
+    end
+
+    def build_delete_sql(connection, table_name)
+      "DELETE FROM #{connection.quote_table_name(table_name)}"
     end
 
     def build_insert_sql(table_name, columns, rows, connection)
@@ -78,19 +101,38 @@ def build_insert_sql(table_name, columns, rows, connection)
       "INSERT INTO #{quoted_table} (#{quoted_columns.join(", ")}) VALUES #{rows.join(", ")}"
     end
 
-    def statements_by_connection(records)
-      deleted_tables = Set.new
+    def verify_foreign_keys!(connection)
+      return unless ActiveRecord.verify_foreign_keys_for_fixtures
 
-      records.each_with_object({}) do |(model, sql), grouped|
-        connection = model.connection
-        grouped[connection] ||= []
+      begin
+        connection.check_all_foreign_keys_valid!
+      rescue ActiveRecord::StatementInvalid => e
+        raise FixtureKit::Error,
+          "Foreign key violations found in cached fixture data. The cache may be " \
+          "stale relative to your current schema or fixture definitions. " \
+          "Original error:\n\n#{e.message}"
+      end
+    end
 
-        table_key = [connection, model.table_name]
-        if deleted_tables.add?(table_key)
-          grouped[connection] << build_delete_sql(model)
-        end
+    def reset_primary_key_sequences(connection, tables)
+      # Rails main (>= 8.2) batches the reset in one round-trip per connection.
+      # Older versions fall back to one query per table.
+      if connection.respond_to?(:reset_column_sequences!)
+        connection.reset_column_sequences!(tables.map { |t| [t] })
+      elsif connection.respond_to?(:reset_pk_sequence!)
+        tables.each { |t| connection.reset_pk_sequence!(t) }
+      end
+    end
+
+    def models_by_pool(data)
+      seen = Set.new
+
+      data.each_with_object({}) do |(model, _), grouped|
+        pool = model.connection_pool
+        next unless seen.add?([pool, model.table_name])
 
-        grouped[connection] << sql if sql
+        grouped[pool] ||= []
+        grouped[pool] << model
       end
     end
   end
diff --git a/spec/dummy/Gemfile b/spec/dummy/Gemfile
index 85a9cf8..3688cf9 100644
--- a/spec/dummy/Gemfile
+++ b/spec/dummy/Gemfile
@@ -3,3 +3,11 @@
 source "https://rubygems.org"
 
 gemspec path: "../.."
+
+group :postgres do
+  gem "pg"
+end
+
+group :mysql do
+  gem "mysql2"
+end
diff --git a/spec/dummy/Gemfile.lock b/spec/dummy/Gemfile.lock
index 82b2f45..8206416 100644
--- a/spec/dummy/Gemfile.lock
+++ b/spec/dummy/Gemfile.lock
@@ -76,6 +76,8 @@ GEM
     minitest (6.0.2)
       drb (~> 2.0)
       prism (~> 1.5)
+    mysql2 (0.5.7)
+      bigdecimal
     nokogiri (1.19.2-aarch64-linux-gnu)
       racc (~> 1.4)
     nokogiri (1.19.2-aarch64-linux-musl)
@@ -92,6 +94,13 @@ GEM
       racc (~> 1.4)
     nokogiri (1.19.2-x86_64-linux-musl)
       racc (~> 1.4)
+    pg (1.6.3)
+    pg (1.6.3-aarch64-linux)
+    pg (1.6.3-aarch64-linux-musl)
+    pg (1.6.3-arm64-darwin)
+    pg (1.6.3-x86_64-darwin)
+    pg (1.6.3-x86_64-linux)
+    pg (1.6.3-x86_64-linux-musl)
     pp (0.6.3)
       prettyprint
     prettyprint (0.2.0)
@@ -181,6 +190,8 @@ DEPENDENCIES
   appraisal
   fixture_kit!
   irb
+  mysql2
+  pg
   railties
   rake
   rspec-rails
@@ -213,6 +224,7 @@ CHECKSUMS
   logger (1.7.0) sha256=196edec7cc44b66cfb40f9755ce11b392f21f7967696af15d274dde7edff0203
   loofah (2.25.1) sha256=d436c73dbd0c1147b16c4a41db097942d217303e1f7728704b37e4df9f6d2e04
   minitest (6.0.2) sha256=db6e57956f6ecc6134683b4c87467d6dd792323c7f0eea7b93f66bd284adbc3d
+  mysql2 (0.5.7) sha256=ba09ede515a0ae8a7192040a1b778c0fb0f025fa5877e9be895cd325fa5e9d7b
   nokogiri (1.19.2-aarch64-linux-gnu) sha256=c34d5c8208025587554608e98fd88ab125b29c80f9352b821964e9a5d5cfbd19
   nokogiri (1.19.2-aarch64-linux-musl) sha256=7f6b4b0202d507326841a4f790294bf75098aef50c7173443812e3ac5cb06515
   nokogiri (1.19.2-arm-linux-gnu) sha256=b7fa1139016f3dc850bda1260988f0d749934a939d04ef2da13bec060d7d5081
@@ -221,6 +233,13 @@ CHECKSUMS
   nokogiri (1.19.2-x86_64-darwin) sha256=7d9af11fda72dfaa2961d8c4d5380ca0b51bc389dc5f8d4b859b9644f195e7a4
   nokogiri (1.19.2-x86_64-linux-gnu) sha256=fa8feca882b73e871a9845f3817a72e9734c8e974bdc4fbad6e4bc6e8076b94f
   nokogiri (1.19.2-x86_64-linux-musl) sha256=93128448e61a9383a30baef041bf1f5817e22f297a1d400521e90294445069a8
+  pg (1.6.3) sha256=1388d0563e13d2758c1089e35e973a3249e955c659592d10e5b77c468f628a99
+  pg (1.6.3-aarch64-linux) sha256=0698ad563e02383c27510b76bf7d4cd2de19cd1d16a5013f375dd473e4be72ea
+  pg (1.6.3-aarch64-linux-musl) sha256=06a75f4ea04b05140146f2a10550b8e0d9f006a79cdaf8b5b130cde40e3ecc2c
+  pg (1.6.3-arm64-darwin) sha256=7240330b572e6355d7c75a7de535edb5dfcbd6295d9c7777df4d9dddfb8c0e5f
+  pg (1.6.3-x86_64-darwin) sha256=ee2e04a17c0627225054ffeb43e31a95be9d7e93abda2737ea3ce4a62f2729d6
+  pg (1.6.3-x86_64-linux) sha256=5d9e188c8f7a0295d162b7b88a768d8452a899977d44f3274d1946d67920ae8d
+  pg (1.6.3-x86_64-linux-musl) sha256=9c9c90d98c72f78eb04c0f55e9618fe55d1512128e411035fe229ff427864009
   pp (0.6.3) sha256=2951d514450b93ccfeb1df7d021cae0da16e0a7f95ee1e2273719669d0ab9df6
   prettyprint (0.2.0) sha256=2bc9e15581a94742064a3cc8b0fb9d45aae3d03a1baa6ef80922627a0766f193
   prism (1.9.0) sha256=7b530c6a9f92c24300014919c9dcbc055bf4cdf51ec30aed099b06cd6674ef85
diff --git a/spec/dummy/app/models/computed_widget.rb b/spec/dummy/app/models/computed_widget.rb
new file mode 100644
index 0000000..b09e76b
--- /dev/null
+++ b/spec/dummy/app/models/computed_widget.rb
@@ -0,0 +1,4 @@
+# frozen_string_literal: true
+
+class ComputedWidget < ApplicationRecord
+end
diff --git a/spec/dummy/config/database.yml b/spec/dummy/config/database.yml
index 86e56f2..938774e 100644
--- a/spec/dummy/config/database.yml
+++ b/spec/dummy/config/database.yml
@@ -1,11 +1,61 @@
+<%
+adapter = ENV.fetch("FIXTURE_KIT_DB", "sqlite3")
+host = ENV.fetch("FIXTURE_KIT_DB_HOST") { adapter == "mysql2" ? "127.0.0.1" : "localhost" }
+username = ENV.fetch("FIXTURE_KIT_DB_USERNAME") do
+  case adapter
+  when "postgresql" then ENV.fetch("USER", "postgres")
+  when "mysql2" then "root"
+  end
+end
+password = ENV["FIXTURE_KIT_DB_PASSWORD"]
+%>
+
 test:
   primary:
+    <% case adapter
+       when "postgresql" %>
+    adapter: postgresql
+    database: fixture_kit_test_primary
+    host: <%= host %>
+    username: <%= username %>
+    password: <%= password %>
+    encoding: unicode
+    pool: 5
+    <% when "mysql2" %>
+    adapter: mysql2
+    database: fixture_kit_test_primary
+    host: <%= host %>
+    username: <%= username %>
+    password: <%= password %>
+    encoding: utf8mb4
+    pool: 5
+    <% else %>
     adapter: sqlite3
     database: tmp/primary_test.sqlite3
     pool: 5
     timeout: 5000
+    <% end %>
   analytics:
+    <% case adapter
+       when "postgresql" %>
+    adapter: postgresql
+    database: fixture_kit_test_analytics
+    host: <%= host %>
+    username: <%= username %>
+    password: <%= password %>
+    encoding: unicode
+    pool: 5
+    <% when "mysql2" %>
+    adapter: mysql2
+    database: fixture_kit_test_analytics
+    host: <%= host %>
+    username: <%= username %>
+    password: <%= password %>
+    encoding: utf8mb4
+    pool: 5
+    <% else %>
     adapter: sqlite3
     database: tmp/analytics_test.sqlite3
     pool: 5
     timeout: 5000
+    <% end %>
diff --git a/spec/integration/pk_sequence_repro_spec.rb b/spec/integration/pk_sequence_repro_spec.rb
new file mode 100644
index 0000000..f57aa36
--- /dev/null
+++ b/spec/integration/pk_sequence_repro_spec.rb
@@ -0,0 +1,59 @@
+# frozen_string_literal: true
+
+require "spec_helper"
+
+# Reproduces issue #51: when a cached fixture is mounted onto a database whose
+# PK generator has not seen the inserted ids (e.g. a parallel test worker with
+# its own DB copy), a subsequent Model.create can collide with one of the
+# explicit ids the cache replayed. Postgres exhibits this; MySQL/SQLite advance
+# their counters from explicit-id inserts and stay safe.
+RSpec.describe "Primary key sequence after fixture mount" do
+  fixture do
+    User.create!(name: "Alice PK Repro", email: "alice-pk-repro@example.com")
+    User.create!(name: "Bob PK Repro", email: "bob-pk-repro@example.com")
+  end
+
+  after do
+    User.connection.disable_referential_integrity do
+      User.connection.execute("DELETE FROM #{User.quoted_table_name}")
+    end
+  end
+
+  it "lets a new record be created without colliding with replayed explicit ids" do
+    # Simulate a parallel-worker scenario: empty table, PK generator at its
+    # initial value. The fixture's auto-mount already populated the table for
+    # us, so wipe and reset before re-mounting.
+    wipe_and_reset_pk!(User)
+
+    declaration = self.class.metadata[FixtureKit::RSpec::DECLARATION_METADATA_KEY]
+    declaration.mount
+
+    expect {
+      User.create!(name: "Charlie PK Repro", email: "charlie-pk-repro@example.com")
+    }.not_to raise_error
+  end
+
+  def wipe_and_reset_pk!(model)
+    connection = model.connection
+    connection.disable_referential_integrity do
+      connection.execute("DELETE FROM #{model.quoted_table_name}")
+    end
+
+    case connection.adapter_name.to_s.downcase
+    when "postgresql"
+      sequence = connection.pk_and_sequence_for(model.table_name)&.last
+      connection.execute("ALTER SEQUENCE #{sequence} RESTART WITH 1") if sequence
+    when "mysql", "mysql2", "trilogy"
+      # MySQL advances AUTO_INCREMENT on explicit-id INSERTs, so the counter
+      # already keeps up with the cached ids. ALTER TABLE ... AUTO_INCREMENT
+      # implicitly commits, which would break the surrounding transactional
+      # fixture, so we leave it alone. The test should still pass on MySQL.
+    when "sqlite"
+      if connection.data_source_exists?("sqlite_sequence")
+        connection.execute("DELETE FROM sqlite_sequence WHERE name = #{connection.quote(model.table_name)}")
+      end
+    else
+      raise "Unsupported adapter for PK reset: #{connection.adapter_name.inspect}"
+    end
+  end
+end
diff --git a/spec/integration/virtual_columns_spec.rb b/spec/integration/virtual_columns_spec.rb
new file mode 100644
index 0000000..a28666a
--- /dev/null
+++ b/spec/integration/virtual_columns_spec.rb
@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+require "spec_helper"
+
+# Models with generated/virtual columns can't accept INSERTs into those
+# columns. The coder must filter them out when building cached statements.
+RSpec.describe "Fixture round-trip with virtual columns" do
+  fixture do
+    ComputedWidget.create!(name: "alpha", quantity: 1)
+    ComputedWidget.create!(name: "beta", quantity: 2)
+  end
+
+  after { ComputedWidget.delete_all }
+
+  it "loads records with their generated column values" do
+    widgets = ComputedWidget.order(:id).to_a
+
+    expect(widgets.map(&:name)).to eq(["alpha", "beta"])
+    expect(widgets.map(&:name_upper)).to eq(["ALPHA", "BETA"])
+  end
+end
diff --git a/spec/support/dummy_rails_helper.rb b/spec/support/dummy_rails_helper.rb
index 8c5f7c0..088d6d4 100644
--- a/spec/support/dummy_rails_helper.rb
+++ b/spec/support/dummy_rails_helper.rb
@@ -25,20 +25,68 @@ def clear_fixture_cache(fixture_name = nil)
   end
 end
 
+class TestDatabaseBootstrap < ActiveRecord::Base
+  self.abstract_class = true
+end
+
+# Ensure non-sqlite test databases exist before connecting (sqlite files auto-create).
+# Uses a separate connection class so the main ActiveRecord::Base connection
+# is established cleanly later from its own configuration.
+def ensure_test_databases_exist!
+  return if ENV.fetch("FIXTURE_KIT_DB", "sqlite3") == "sqlite3"
+
+  ActiveRecord::Base.configurations.configs_for(env_name: "test").each do |db_config|
+    create_database_if_missing(db_config)
+  end
+end
+
+def create_database_if_missing(db_config)
+  config = db_config.configuration_hash.dup
+  database = config[:database]
+
+  case config[:adapter]
+  when "postgresql"
+    config = config.merge(database: "postgres")
+  when "mysql2"
+    config = config.except(:database)
+  else
+    return
+  end
+
+  bootstrap = TestDatabaseBootstrap
+  bootstrap.remove_connection if bootstrap.connected?
+  bootstrap.establish_connection(config)
+  quoted = bootstrap.connection.quote_column_name(database)
+
+  case db_config.adapter
+  when "postgresql"
+    bootstrap.connection.execute("CREATE DATABASE #{quoted}")
+  when "mysql2"
+    bootstrap.connection.execute("CREATE DATABASE IF NOT EXISTS #{quoted}")
+  end
+rescue ActiveRecord::StatementInvalid => e
+  raise unless e.message.include?("already exists")
+ensure
+  TestDatabaseBootstrap.remove_connection if TestDatabaseBootstrap.connected?
+end
+
 # Create schema for both databases
 def setup_databases
+  ensure_test_databases_exist!
+
   ActiveRecord::Base.connection.disable_referential_integrity do
-    ActiveRecord::Base.connection.drop_table(:comments, if_exists: true)
-    ActiveRecord::Base.connection.drop_table(:tasks, if_exists: true)
-    ActiveRecord::Base.connection.drop_table(:projects, if_exists: true)
-    ActiveRecord::Base.connection.drop_table(:users, if_exists: true)
-    ActiveRecord::Base.connection.drop_table(:vehicles, if_exists: true)
-    ActiveRecord::Base.connection.drop_table(:gadgets, if_exists: true)
+    ActiveRecord::Base.connection.drop_table(:comments, if_exists: true, force: :cascade)
+    ActiveRecord::Base.connection.drop_table(:tasks, if_exists: true, force: :cascade)
+    ActiveRecord::Base.connection.drop_table(:projects, if_exists: true, force: :cascade)
+    ActiveRecord::Base.connection.drop_table(:users, if_exists: true, force: :cascade)
+    ActiveRecord::Base.connection.drop_table(:vehicles, if_exists: true, force: :cascade)
+    ActiveRecord::Base.connection.drop_table(:gadgets, if_exists: true, force: :cascade)
+    ActiveRecord::Base.connection.drop_table(:computed_widgets, if_exists: true, force: :cascade)
   end
 
   AnalyticsRecord.connection.disable_referential_integrity do
-    AnalyticsRecord.connection.drop_table(:activity_logs, if_exists: true)
-    AnalyticsRecord.connection.drop_table(:time_entries, if_exists: true)
+    AnalyticsRecord.connection.drop_table(:activity_logs, if_exists: true, force: :cascade)
+    AnalyticsRecord.connection.drop_table(:time_entries, if_exists: true, force: :cascade)
   end
 
   # Primary database schema
@@ -88,6 +136,13 @@ def setup_databases
     t.timestamps
   end
 
+  ActiveRecord::Base.connection.create_table :computed_widgets, force: true do |t|
+    t.string :name, null: false
+    t.integer :quantity, null: false, default: 0
+    t.virtual :name_upper, type: :string, as: "UPPER(name)", stored: true
+    t.timestamps
+  end
+
   # Analytics database schema
   AnalyticsRecord.connection.create_table :activity_logs, force: true do |t|
     t.integer :external_user_id, null: false
diff --git a/spec/unit/coders/active_record_coder_spec.rb b/spec/unit/coders/active_record_coder_spec.rb
index 78099b2..5dc75a3 100644
--- a/spec/unit/coders/active_record_coder_spec.rb
+++ b/spec/unit/coders/active_record_coder_spec.rb
@@ -20,14 +20,16 @@ def exercise_user_write_operations(suffix)
       { name: "Bulk Insert 2 #{suffix}", email: "bulk-insert-2-#{suffix}@example.com" }
     ])
 
+    upsert_options = upsert_all_options(User)
+
     User.upsert_all([
       { id: user.id, name: "Upsert #{suffix}", email: "create-#{suffix}@example.com" }
-    ], unique_by: :id)
+    ], **upsert_options)
 
     User.upsert_all([
       { id: user.id, name: "Bulk Upsert Existing #{suffix}", email: "create-#{suffix}@example.com" },
       { id: user.id + 10_000_000, name: "Bulk Upsert New #{suffix}", email: "bulk-upsert-#{suffix}@example.com" }
-    ], unique_by: :id)
+    ], **upsert_options)
 
     doomed = User.create!(name: "Delete #{suffix}", email: "delete-#{suffix}@example.com")
     User.where(id: doomed.id).delete_all
@@ -36,6 +38,13 @@ def exercise_user_write_operations(suffix)
     destroyed.destroy!
   end
 
+  # MySQL's upsert uses ON DUPLICATE KEY UPDATE and rejects :unique_by;
+  # Postgres requires it to target the conflict.
+  def upsert_all_options(model)
+    return {} if model.connection.adapter_name.to_s.downcase.start_with?("mysql", "trilogy")
+    { unique_by: :id }
+  end
+
   describe "#generate" do
     it "captures user model writes for all supported write operation types" do
       suffix = SecureRandom.hex(6)
@@ -140,11 +149,121 @@ def exercise_user_write_operations(suffix)
       ]
 
       expect(primary_connection).to receive(:disable_referential_integrity).once.and_yield
-      expect(primary_connection).to receive(:execute_batch).with(primary_statements, "FixtureKit Load").once
+      expect(primary_connection).to receive(:execute_batch).with(primary_statements, "FixtureKit Insert").once
       expect(analytics_connection).to receive(:disable_referential_integrity).once.and_yield
-      expect(analytics_connection).to receive(:execute_batch).with(analytics_statements, "FixtureKit Load").once
+      expect(analytics_connection).to receive(:execute_batch).with(analytics_statements, "FixtureKit Insert").once
+
+      coder.mount(records)
+    end
+
+    it "uses the batched reset_column_sequences! when the adapter exposes it" do
+      records = {
+        User => "INSERT INTO users (id, name) VALUES (1, 'Alice')",
+        Project => "INSERT INTO projects (id, name, owner_id) VALUES (1, 'Website', 1)"
+      }
+
+      fake_connection = stub_fake_connection
+      allow(fake_connection).to receive(:respond_to?).with(:reset_column_sequences!).and_return(true)
+      allow(fake_connection).to receive(:reset_column_sequences!)
+      stub_shared_pool([User, Project], fake_connection)
+
+      coder.mount(records)
+
+      expect(fake_connection).to have_received(:reset_column_sequences!)
+        .with([[User.table_name], [Project.table_name]]).once
+    end
+
+    it "falls back to per-table reset_pk_sequence! when reset_column_sequences! is unavailable" do
+      records = { User => "INSERT INTO users (id, name) VALUES (1, 'Alice')" }
+
+      fake_connection = stub_fake_connection
+      allow(fake_connection).to receive(:respond_to?).with(:reset_pk_sequence!).and_return(true)
+      allow(fake_connection).to receive(:reset_pk_sequence!)
+      stub_pool(User, fake_connection)
 
       coder.mount(records)
+
+      expect(fake_connection).to have_received(:reset_pk_sequence!).with(User.table_name).once
+    end
+
+    it "skips PK sequence reset on adapters that expose neither method" do
+      records = { User => "INSERT INTO users (id, name) VALUES (1, 'Alice')" }
+
+      fake_connection = stub_fake_connection
+      stub_pool(User, fake_connection)
+
+      expect { coder.mount(records) }.not_to raise_error
+    end
+
+    context "when ActiveRecord.verify_foreign_keys_for_fixtures is true" do
+      around do |example|
+        previous = ActiveRecord.verify_foreign_keys_for_fixtures
+        ActiveRecord.verify_foreign_keys_for_fixtures = true
+        example.run
+      ensure
+        ActiveRecord.verify_foreign_keys_for_fixtures = previous
+      end
+
+      it "calls check_all_foreign_keys_valid! after the batch executes" do
+        records = { User => "INSERT INTO users (id, name) VALUES (1, 'Alice')" }
+        fake_connection = stub_fake_connection
+        stub_pool(User, fake_connection)
+
+        coder.mount(records)
+
+        expect(fake_connection).to have_received(:check_all_foreign_keys_valid!).once
+      end
+
+      it "wraps an FK violation in a FixtureKit::Error with a hint about stale cache" do
+        records = { User => "INSERT INTO users (id, name) VALUES (1, 'Alice')" }
+        fake_connection = stub_fake_connection
+        allow(fake_connection).to receive(:check_all_foreign_keys_valid!)
+          .and_raise(ActiveRecord::StatementInvalid, "Foreign key violations found: orders")
+        stub_pool(User, fake_connection)
+
+        expect { coder.mount(records) }.to raise_error(FixtureKit::Error, /cached fixture data.*stale.*Foreign key violations found: orders/m)
+      end
+    end
+
+    context "when ActiveRecord.verify_foreign_keys_for_fixtures is false" do
+      around do |example|
+        previous = ActiveRecord.verify_foreign_keys_for_fixtures
+        ActiveRecord.verify_foreign_keys_for_fixtures = false
+        example.run
+      ensure
+        ActiveRecord.verify_foreign_keys_for_fixtures = previous
+      end
+
+      it "does not call check_all_foreign_keys_valid!" do
+        records = { User => "INSERT INTO users (id, name) VALUES (1, 'Alice')" }
+        fake_connection = stub_fake_connection
+        stub_pool(User, fake_connection)
+
+        coder.mount(records)
+
+        expect(fake_connection).not_to have_received(:check_all_foreign_keys_valid!)
+      end
+    end
+
+    def stub_fake_connection
+      fake_connection = double("connection")
+      allow(fake_connection).to receive(:disable_referential_integrity).and_yield
+      allow(fake_connection).to receive(:execute_batch)
+      allow(fake_connection).to receive(:quote_table_name) { |name| %("#{name}") }
+      allow(fake_connection).to receive(:respond_to?).with(:reset_column_sequences!).and_return(false)
+      allow(fake_connection).to receive(:respond_to?).with(:reset_pk_sequence!).and_return(false)
+      allow(fake_connection).to receive(:check_all_foreign_keys_valid!)
+      fake_connection
+    end
+
+    def stub_pool(model, connection)
+      stub_shared_pool([model], connection)
+    end
+
+    def stub_shared_pool(models, connection)
+      pool = double("pool-for-#{models.map(&:name).join('-')}")
+      allow(pool).to receive(:with_connection).and_yield(connection)
+      models.each { |m| allow(m).to receive(:connection_pool).and_return(pool) }
     end
   end
 
diff --git a/spec/unit/fixture_cache_spec.rb b/spec/unit/fixture_cache_spec.rb
index 4f7d8f5..8d4a1bf 100644
--- a/spec/unit/fixture_cache_spec.rb
+++ b/spec/unit/fixture_cache_spec.rb
@@ -356,9 +356,9 @@ def identifier_for(identifier)
       ]
 
       expect(primary_connection).to receive(:disable_referential_integrity).once.and_yield
-      expect(primary_connection).to receive(:execute_batch).with(primary_statements, "FixtureKit Load").once
+      expect(primary_connection).to receive(:execute_batch).with(primary_statements, "FixtureKit Insert").once
       expect(analytics_connection).to receive(:disable_referential_integrity).once.and_yield
-      expect(analytics_connection).to receive(:execute_batch).with(analytics_statements, "FixtureKit Load").once
+      expect(analytics_connection).to receive(:execute_batch).with(analytics_statements, "FixtureKit Insert").once
 
       expect(cache.load).to eq(:repository)
     end