3 files changed, 75 insertions, 0 deletions
diff --git a/app/models/ml/experiment.rb b/app/models/ml/experiment.rb
index d1277efac7b..5c5f8d3b2db 100644
--- a/app/models/ml/experiment.rb
+++ b/app/models/ml/experiment.rb
@@ -11,6 +11,7 @@ module Ml
 
     belongs_to :project
     belongs_to :user
+    belongs_to :model, optional: true, inverse_of: :default_experiment
     has_many :candidates, class_name: 'Ml::Candidate'
     has_many :metadata, class_name: 'Ml::ExperimentMetadata'
 
@@ -22,10 +23,21 @@ module Ml
 
     has_internal_id :iid, scope: :project
 
+    before_destroy :stop_destroy
+
     def package_name
       "#{PACKAGE_PREFIX}#{iid}"
     end
 
+    def stop_destroy
+      return unless model_id
+
+      errors[:base] << "Cannot delete an experiment associated to a model"
+      # According to docs, throw is the correct way to stop on a callback
+      # https://api.rubyonrails.org/classes/ActiveRecord/Callbacks.html#module-ActiveRecord::Callbacks-label-Canceling+callbacks
+      throw :abort # rubocop:disable Cop/BanCatchThrow
+    end
+
     class << self
       def by_project_id_and_iid(project_id, iid)
         find_by(project_id: project_id, iid: iid)
diff --git a/app/models/ml/model.rb b/app/models/ml/model.rb
new file mode 100644
index 00000000000..684b8e1983b
--- /dev/null
+++ b/app/models/ml/model.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+module Ml
+  class Model < ApplicationRecord
+    validates :project, :default_experiment, presence: true
+    validates :name,
+      format: Gitlab::Regex.ml_model_name_regex,
+      uniqueness: { scope: :project },
+      presence: true,
+      length: { maximum: 255 }
+
+    validate :valid_default_experiment?
+
+    has_one :default_experiment, class_name: 'Ml::Experiment'
+    belongs_to :project
+    has_many :versions, class_name: 'Ml::ModelVersion'
+
+    def valid_default_experiment?
+      return unless default_experiment
+
+      errors.add(:default_experiment) unless default_experiment.name == name
+      errors.add(:default_experiment) unless default_experiment.project_id == project_id
+    end
+  end
+end
diff --git a/app/models/ml/model_version.rb b/app/models/ml/model_version.rb
new file mode 100644
index 00000000000..540fe6018a1
--- /dev/null
+++ b/app/models/ml/model_version.rb
@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+module Ml
+  class ModelVersion < ApplicationRecord
+    validates :project, :model, presence: true
+
+    validates :version,
+      format: Gitlab::Regex.ml_model_version_regex,
+      uniqueness: { scope: [:project, :model_id] },
+      presence: true,
+      length: { maximum: 255 }
+
+    validate :valid_model?, :valid_package?
+
+    belongs_to :model, class_name: 'Ml::Model'
+    belongs_to :project
+    belongs_to :package, class_name: 'Packages::Package', optional: true
+
+    delegate :name, to: :model
+
+    private
+
+    def valid_model?
+      return unless model
+
+      errors.add(:model, 'model project must be the same') unless model.project_id == project_id
+    end
+
+    def valid_package?
+      return unless package
+
+      errors.add(:package, 'package must be ml_model') unless package.ml_model?
+      errors.add(:package, 'package name must be the same') unless package.name == name
+      errors.add(:package, 'package version must be the same') unless package.version == version
+      errors.add(:package, 'package project must be the same') unless package.project_id == project_id
+    end
+  end
+end