diff --git a/lib/sql_ecto/hr/country.ex b/lib/sql_ecto/hr/country.ex
index 1f40e8c..45eae18 100644
--- a/lib/sql_ecto/hr/country.ex
+++ b/lib/sql_ecto/hr/country.ex
@@ -2,7 +2,7 @@ defmodule SqlEcto.Hr.Country do
   use Ecto.Schema
   import Ecto.Changeset
 
-  @primary_key {:country_id, :string, []}
+  @primary_key {:country_id, :string, autogenerate: false}
 
   schema "countries" do
 
diff --git a/lib/sql_ecto/hr/department.ex b/lib/sql_ecto/hr/department.ex
index 33442bb..dbdfcf1 100644
--- a/lib/sql_ecto/hr/department.ex
+++ b/lib/sql_ecto/hr/department.ex
@@ -2,7 +2,7 @@ defmodule SqlEcto.Hr.Department do
   use Ecto.Schema
   import Ecto.Changeset
 
-  @primary_key {:department_id, :integer, []}
+  @primary_key {:department_id, :integer, autogenerate: false}
 
   schema "departments" do
 
@@ -11,6 +11,7 @@ defmodule SqlEcto.Hr.Department do
 
   end
 
+  @spec changeset(Ecto.Changeset.t(), any()) :: Ecto.Changeset.t()
   def changeset(departments, _params) do
     departments
     |> validate_required(:department_name)
diff --git a/lib/sql_ecto/hr/dependent.ex b/lib/sql_ecto/hr/dependent.ex
index bdab563..6dcf30c 100644
--- a/lib/sql_ecto/hr/dependent.ex
+++ b/lib/sql_ecto/hr/dependent.ex
@@ -2,7 +2,7 @@ defmodule SqlEcto.Hr.Dependent do
   use Ecto.Schema
   import Ecto.Changeset
 
-  @primary_key {:dependent_id, :integer, []}
+  @primary_key {:dependent_id, :integer, autogenerate: false}
 
   schema "dependents" do
 
diff --git a/lib/sql_ecto/hr/employee.ex b/lib/sql_ecto/hr/employee.ex
index 805d42d..7b72661 100644
--- a/lib/sql_ecto/hr/employee.ex
+++ b/lib/sql_ecto/hr/employee.ex
@@ -2,7 +2,7 @@ defmodule SqlEcto.Hr.Employee do
   use Ecto.Schema
   import Ecto.Changeset
 
-  @primary_key {:employee_id, :integer, []}
+  @primary_key {:employee_id, :integer, autogenerate: false}
 
   schema "employees" do
 
@@ -18,6 +18,7 @@ defmodule SqlEcto.Hr.Employee do
 
   end
 
+  @spec changeset(Ecto.Changeset.t(), any()) :: Ecto.Changeset.t()
   def changeset(employees, _params) do
     employees
     |> validate_required(:last_name)
diff --git a/lib/sql_ecto/hr/job.ex b/lib/sql_ecto/hr/job.ex
index 6606fb4..2fd0644 100644
--- a/lib/sql_ecto/hr/job.ex
+++ b/lib/sql_ecto/hr/job.ex
@@ -2,7 +2,7 @@ defmodule SqlEcto.Hr.Job do
   use Ecto.Schema
   import Ecto.Changeset
 
-  @primary_key {:job_id, :integer, []}
+  @primary_key {:job_id, :integer, autogenerate: false}
 
   schema "jobs" do
 
diff --git a/lib/sql_ecto/hr/location.ex b/lib/sql_ecto/hr/location.ex
index d294d4e..5acc98a 100644
--- a/lib/sql_ecto/hr/location.ex
+++ b/lib/sql_ecto/hr/location.ex
@@ -2,7 +2,7 @@ defmodule SqlEcto.Hr.Location do
   use Ecto.Schema
   import Ecto.Changeset
 
-  @primary_key {:location_id, :integer, []}
+  @primary_key {:location_id, :integer, autogenerate: false}
 
   schema "locations" do
 
diff --git a/lib/sql_ecto/hr/region.ex b/lib/sql_ecto/hr/region.ex
index 3c5b0c5..8af2b97 100644
--- a/lib/sql_ecto/hr/region.ex
+++ b/lib/sql_ecto/hr/region.ex
@@ -2,7 +2,7 @@ defmodule SqlEcto.Hr.Region do
   use Ecto.Schema
   import Ecto.Changeset
 
-  @primary_key {:region_id, :integer, []}
+  @primary_key {:region_id, :integer, autogenerate: false}
 
   schema "regions" do
 
diff --git a/priv/repo/migrations/20231101035925_create_regions.exs b/priv/repo/migrations/20231101035925_create_regions.exs
new file mode 100644
index 0000000..b1d6ab6
--- /dev/null
+++ b/priv/repo/migrations/20231101035925_create_regions.exs
@@ -0,0 +1,10 @@
+defmodule SqlEcto.Repo.Migrations.CreateRegions do
+  use Ecto.Migration
+
+  def change do
+    create table(:regions, primary_key: false) do
+      add :region_id, :serial, primary_key: true
+      add :region_name, :string, size: 25
+    end
+  end
+end
diff --git a/priv/repo/migrations/20231102033546_create_countries.exs b/priv/repo/migrations/20231102033546_create_countries.exs
new file mode 100644
index 0000000..61627d4
--- /dev/null
+++ b/priv/repo/migrations/20231102033546_create_countries.exs
@@ -0,0 +1,11 @@
+defmodule SqlEcto.Repo.Migrations.CreateCountries do
+  use Ecto.Migration
+
+  def change do
+    create table(:countries, primary_key: false) do
+      add :country_id, :string, primary_key: true, size: 2
+      add :country_name, :string, size: 40
+      add :region_id, references("regions", column: :region_id, type: :serial, on_update: :update_all, on_delete: :delete_all), null: false
+    end
+  end
+end
diff --git a/priv/repo/migrations/20231102035048_create_locations.exs b/priv/repo/migrations/20231102035048_create_locations.exs
new file mode 100644
index 0000000..c5070b7
--- /dev/null
+++ b/priv/repo/migrations/20231102035048_create_locations.exs
@@ -0,0 +1,16 @@
+defmodule SqlEcto.Repo.Migrations.CreateLocations do
+  use Ecto.Migration
+
+  def change do
+    create table("locations", primary_key: false) do
+      add :location_id, :serial, primary_key: true
+      add :street_address, :string, size: 40
+      add :postal_code, :string, size: 12
+      add :city, :string, size: 30, null: false
+      add :state_province, :string, size: 25
+      add :country_id, references("countries", type: :string, column: :country_id, on_update: :update_all, on_delete: :delete_all), null: false, size: 2
+
+    end
+
+  end
+end
diff --git a/priv/repo/migrations/20231102040321_create_departments.exs b/priv/repo/migrations/20231102040321_create_departments.exs
new file mode 100644
index 0000000..1ba1a33
--- /dev/null
+++ b/priv/repo/migrations/20231102040321_create_departments.exs
@@ -0,0 +1,11 @@
+defmodule SqlEcto.Repo.Migrations.CreateDepartments do
+  use Ecto.Migration
+
+  def change do
+    create table("departments", primary_key: false) do
+      add :department_id, :serial, primary_key: true
+      add :department_name, :string, size: 30, null: false
+      add :location_id, references("locations", type: :serial, column: :location_id, on_update: :update_all, on_delete: :delete_all)
+    end
+  end
+end
diff --git a/priv/repo/migrations/20231102041246_create_jobs.exs b/priv/repo/migrations/20231102041246_create_jobs.exs
new file mode 100644
index 0000000..a1c94cd
--- /dev/null
+++ b/priv/repo/migrations/20231102041246_create_jobs.exs
@@ -0,0 +1,12 @@
+defmodule SqlEcto.Repo.Migrations.CreateJobs do
+  use Ecto.Migration
+
+  def change do
+    create table(:jobs, primary_key: false) do
+      add :job_id, :serial, primary_key: true
+      add :job_title, :string, size: 35, null: false
+      add :min_salary, :decimal, precision: 8, scale: 2
+      add :max_salary, :decimal, precision: 8, scale: 2
+    end
+  end
+end
diff --git a/priv/repo/migrations/20231102042459_create_employees.exs b/priv/repo/migrations/20231102042459_create_employees.exs
new file mode 100644
index 0000000..5757a80
--- /dev/null
+++ b/priv/repo/migrations/20231102042459_create_employees.exs
@@ -0,0 +1,18 @@
+defmodule SqlEcto.Repo.Migrations.CreateEmployees do
+  use Ecto.Migration
+
+  def change do
+    create table("employees", primary_key: false) do
+      add :employee_id, :serial, primary_key: true
+      add :first_name, :string, size: 20
+      add :last_name, :string, size: 25, null: false
+      add :email, :string, size: 100, null: false
+      add :phone_number, :string, size: 20
+      add :hire_date, :date, null: false
+      add :salary, :decimal, precision: 8, scale: 2, null: false
+      add :job_id, references("jobs", type: :serial, column: :job_id, on_update: :update_all, on_delete: :delete_all)
+      add :department_id, references("departments", type: :serial, column: :department_id, on_update: :update_all, on_delete: :delete_all)
+      add :manager_id, references("employees", type: :serial, column: :employee_id, on_update: :update_all, on_delete: :delete_all)
+    end
+  end
+end
diff --git a/priv/repo/migrations/20231102044510_create_dependents.exs b/priv/repo/migrations/20231102044510_create_dependents.exs
new file mode 100644
index 0000000..b501bda
--- /dev/null
+++ b/priv/repo/migrations/20231102044510_create_dependents.exs
@@ -0,0 +1,13 @@
+defmodule SqlEcto.Repo.Migrations.CreateDependents do
+  use Ecto.Migration
+
+  def change do
+    create table("dependents", primary_key: false) do
+     add :dependent_id, :serial, primary_key: true
+     add :first_name, :string, size: 50, null: false
+     add :last_name, :string, size: 50, null: false
+     add :relationship, :string, size: 25, null: false
+     add :employee_id, references("employees", type: :serial, column: :employee_id, on_update: :update_all, on_delete: :delete_all), null: false
+    end
+  end
+end