diff --git a/app/models/project.rb b/app/models/project.rb
index be4960aef8af34c1fcffab32bbee207d9dbf8aaf..65745fd6d3707e91c57547cea7973e675ee654b4 100644
--- a/app/models/project.rb
+++ b/app/models/project.rb
@@ -175,7 +175,7 @@ class Project < ActiveRecord::Base
   has_many :builds, class_name: 'Ci::Build' # the builds are created from the commit_statuses
   has_many :runner_projects, dependent: :destroy, class_name: 'Ci::RunnerProject'
   has_many :runners, through: :runner_projects, source: :runner, class_name: 'Ci::Runner'
-  has_many :variables, dependent: :destroy, class_name: 'Ci::Variable'
+  has_many :variables, class_name: 'Ci::Variable'
   has_many :triggers, dependent: :destroy, class_name: 'Ci::Trigger'
   has_many :environments, dependent: :destroy
   has_many :deployments, dependent: :destroy
diff --git a/changelogs/unreleased/zj-clean-up-ci-variables-table.yml b/changelogs/unreleased/zj-clean-up-ci-variables-table.yml
new file mode 100644
index 0000000000000000000000000000000000000000..ea2db40d590351eb3d38f0d46a22a84bd95839a5
--- /dev/null
+++ b/changelogs/unreleased/zj-clean-up-ci-variables-table.yml
@@ -0,0 +1,4 @@
+---
+title: Cleanup ci_variables schema and table
+merge_request:
+author:
diff --git a/db/migrate/20170508190732_add_foreign_key_to_ci_variables.rb b/db/migrate/20170508190732_add_foreign_key_to_ci_variables.rb
index 1383732478777047c981f8e0e88de6dbb779b216..20ecaa2c36c2a02ef4241314574e7c987d1e8f5a 100644
--- a/db/migrate/20170508190732_add_foreign_key_to_ci_variables.rb
+++ b/db/migrate/20170508190732_add_foreign_key_to_ci_variables.rb
@@ -13,7 +13,6 @@ class AddForeignKeyToCiVariables < ActiveRecord::Migration
         FROM projects
         WHERE projects.id = ci_variables.project_id
       )
-      OR ci_variables.project_id IS NULL
     SQL
 
     add_concurrent_foreign_key(:ci_variables, :projects, column: :project_id)
diff --git a/spec/factories/ci/variables.rb b/spec/factories/ci/variables.rb
index 6653f0bb5c3897578b8b411798f4f476ac2e1c5d..c5fba597c1cff6ea0c2664927c5cb9b8f410abde 100644
--- a/spec/factories/ci/variables.rb
+++ b/spec/factories/ci/variables.rb
@@ -2,5 +2,7 @@ FactoryGirl.define do
   factory :ci_variable, class: Ci::Variable do
     sequence(:key) { |n| "VARIABLE_#{n}" }
     value 'VARIABLE_VALUE'
+
+    project factory: :empty_project
   end
 end
diff --git a/spec/models/ci/variable_spec.rb b/spec/models/ci/variable_spec.rb
index 048d25869bc92e2eb202457d55415279345f2796..fe8c52d53536df840b1e49c79d5d3673b1ca22f4 100644
--- a/spec/models/ci/variable_spec.rb
+++ b/spec/models/ci/variable_spec.rb
@@ -1,7 +1,7 @@
 require 'spec_helper'
 
 describe Ci::Variable, models: true do
-  subject { Ci::Variable.new }
+  subject { build(:ci_variable) }
 
   let(:secret_value) { 'secret' }