diff --git a/lib/galaxies/planet_building.ex b/lib/galaxies/planet_building.ex
index 56e7217..3635eec 100644
--- a/lib/galaxies/planet_building.ex
+++ b/lib/galaxies/planet_building.ex
@@ -8,7 +8,7 @@ defmodule Galaxies.PlanetBuilding do
     field :current_level, :integer
 
     belongs_to :planet, Galaxies.Planet, primary_key: true
-    belongs_to :building, Galaxies.Building, primary_key: true
+    belongs_to :building, Galaxies.Building, primary_key: true, type: :integer
 
     timestamps(type: :utc_datetime_usec)
   end
diff --git a/lib/galaxies/planet_unit.ex b/lib/galaxies/planet_unit.ex
index 18ab46c..66b21ed 100644
--- a/lib/galaxies/planet_unit.ex
+++ b/lib/galaxies/planet_unit.ex
@@ -6,7 +6,7 @@ defmodule Galaxies.PlanetUnit do
     field :amount, :integer
 
     belongs_to :planet, Galaxies.Planet, primary_key: true
-    belongs_to :unit, Galaxies.Unit, primary_key: true
+    belongs_to :unit, Galaxies.Unit, primary_key: true, type: :integer
 
     timestamps(type: :utc_datetime_usec)
   end
diff --git a/lib/galaxies/planets.ex b/lib/galaxies/planets.ex
index 8aaf1f0..34d5b0c 100644
--- a/lib/galaxies/planets.ex
+++ b/lib/galaxies/planets.ex
@@ -40,6 +40,7 @@ defmodule Galaxies.Planets do
           )
 
         planet_building = Enum.find(planet_buildings, fn pb -> pb.building_id == building_id end)
+        dbg(planet_building)
 
         {cost_metal, cost_crystal, cost_deuterium, _energy} =
           Galaxies.calc_upgrade_cost(planet_building.building.upgrade_cost_formula, level)
diff --git a/lib/galaxies/planets/enqueued_building.ex b/lib/galaxies/planets/enqueued_building.ex
index dcfe98d..602bb5b 100644
--- a/lib/galaxies/planets/enqueued_building.ex
+++ b/lib/galaxies/planets/enqueued_building.ex
@@ -17,7 +17,7 @@ defmodule Galaxies.Planets.EnqueuedBuilding do
     field :started_at, :utc_datetime
     field :completed_at, :utc_datetime
 
-    belongs_to :building, Galaxies.Building
+    belongs_to :building, Galaxies.Building, type: :integer
     belongs_to :planet, Galaxies.Planet
 
     timestamps(type: :utc_datetime_usec)
diff --git a/lib/galaxies/unit.ex b/lib/galaxies/unit.ex
index 9e000a4..48bb72a 100644
--- a/lib/galaxies/unit.ex
+++ b/lib/galaxies/unit.ex
@@ -1,9 +1,10 @@
 defmodule Galaxies.Unit do
   @moduledoc """
   Defines the schema for the unit of the game.
+  Uses integer IDs for simplicity.
   """
 
-  use Galaxies.Schema
+  use Ecto.Schema
 
   schema "units" do
     field :name, :string
diff --git a/lib/galaxies_web/live/facilities_live.ex b/lib/galaxies_web/live/facilities_live.ex
index f5511b6..7894e5a 100644
--- a/lib/galaxies_web/live/facilities_live.ex
+++ b/lib/galaxies_web/live/facilities_live.ex
@@ -208,7 +208,11 @@ defmodule GalaxiesWeb.FacilitiesLive do
 
     level = building.current_level + 1
 
-    case Accounts.upgrade_planet_building(socket.assigns.current_planet, building_id, level) do
+    case Accounts.upgrade_planet_building(
+           socket.assigns.current_planet,
+           String.to_integer(building_id),
+           level
+         ) do
       :ok ->
         # TODO: doing the same as mount seems a bit too much, try to optimize
         current_planet = Accounts.get_active_planet(socket.assigns.current_player)
diff --git a/lib/galaxies_web/live/resources_live.ex b/lib/galaxies_web/live/resources_live.ex
index 0c77dc2..7c433a8 100644
--- a/lib/galaxies_web/live/resources_live.ex
+++ b/lib/galaxies_web/live/resources_live.ex
@@ -208,7 +208,11 @@ defmodule GalaxiesWeb.ResourcesLive do
 
     level = building.current_level + 1
 
-    case Accounts.upgrade_planet_building(socket.assigns.current_planet, building_id, level) do
+    case Accounts.upgrade_planet_building(
+           socket.assigns.current_planet,
+           String.to_integer(building_id),
+           level
+         ) do
       :ok ->
         # TODO: doing the same as mount seems a bit too much, try to optimize
         current_planet = Accounts.get_active_planet(socket.assigns.current_player)
diff --git a/priv/repo/migrations/20240126093746_create_buildings_table.exs b/priv/repo/migrations/20240126093746_create_buildings_table.exs
index a148486..ebed51c 100644
--- a/priv/repo/migrations/20240126093746_create_buildings_table.exs
+++ b/priv/repo/migrations/20240126093746_create_buildings_table.exs
@@ -3,7 +3,6 @@ defmodule Galaxies.Repo.Migrations.CreateBuildingsTable do
 
   def change do
     create table(:buildings) do
-      # add :id, :binary_id, primary_key: true
       add :name, :string, null: false
 
       add :short_description, :text, null: false
diff --git a/priv/repo/migrations/20240129163345_create_units_table.exs b/priv/repo/migrations/20240129163345_create_units_table.exs
index 349e2ef..9488866 100644
--- a/priv/repo/migrations/20240129163345_create_units_table.exs
+++ b/priv/repo/migrations/20240129163345_create_units_table.exs
@@ -2,8 +2,7 @@ defmodule Galaxies.Repo.Migrations.CreateUnitsTable do
   use Ecto.Migration
 
   def change do
-    create table(:units, primary_key: false) do
-      add :id, :binary_id, primary_key: true
+    create table(:units) do
       add :name, :string, null: false
 
       add :short_description, :text, null: false
@@ -37,7 +36,7 @@ defmodule Galaxies.Repo.Migrations.CreateUnitsTable do
         null: false,
         primary_key: true
 
-      add :unit_id, references(:units, type: :binary_id, on_delete: :delete_all),
+      add :unit_id, references(:units, on_delete: :delete_all),
         null: false,
         primary_key: true
 
diff --git a/priv/repo/migrations/20240129223345_insert_units.exs b/priv/repo/migrations/20240129223345_insert_units.exs
index e9f4351..9ad25ba 100644
--- a/priv/repo/migrations/20240129223345_insert_units.exs
+++ b/priv/repo/migrations/20240129223345_insert_units.exs
@@ -8,6 +8,7 @@ defmodule Galaxies.Repo.Migrations.InsertUnits do
 
     Repo.insert_all(Galaxies.Unit, [
       %{
+        id: 101,
         name: "Light Fighter",
         list_order: 10,
         image_src: "/images/units/light-fighter.webp",
@@ -23,6 +24,7 @@ defmodule Galaxies.Repo.Migrations.InsertUnits do
         updated_at: now
       },
       %{
+        id: 102,
         name: "Heavy Fighter",
         list_order: 20,
         image_src: "/images/units/heavy-fighter.webp",
@@ -38,6 +40,7 @@ defmodule Galaxies.Repo.Migrations.InsertUnits do
         updated_at: now
       },
       %{
+        id: 103,
         name: "Cruiser",
         list_order: 10,
         image_src: "/images/units/cruiser.webp",
@@ -53,6 +56,7 @@ defmodule Galaxies.Repo.Migrations.InsertUnits do
         updated_at: now
       },
       %{
+        id: 104,
         name: "Battleship",
         list_order: 10,
         image_src: "/images/units/battleship.webp",
@@ -68,6 +72,7 @@ defmodule Galaxies.Repo.Migrations.InsertUnits do
         updated_at: now
       },
       %{
+        id: 105,
         name: "Interceptor",
         list_order: 10,
         image_src: "/images/units/interceptor.webp",
@@ -83,6 +88,7 @@ defmodule Galaxies.Repo.Migrations.InsertUnits do
         updated_at: now
       },
       %{
+        id: 106,
         name: "Bomber",
         list_order: 10,
         image_src: "/images/units/bombardier.webp",
@@ -98,6 +104,7 @@ defmodule Galaxies.Repo.Migrations.InsertUnits do
         updated_at: now
       },
       %{
+        id: 107,
         name: "Destroyer",
         list_order: 10,
         image_src: "/images/units/dreadnaught.webp",
@@ -113,6 +120,7 @@ defmodule Galaxies.Repo.Migrations.InsertUnits do
         updated_at: now
       },
       %{
+        id: 108,
         name: "Reaper",
         list_order: 10,
         image_src: "/images/units/battleship-v3.webp",
@@ -128,6 +136,7 @@ defmodule Galaxies.Repo.Migrations.InsertUnits do
         updated_at: now
       },
       %{
+        id: 109,
         name: "Deathstar",
         list_order: 10,
         image_src: "/images/units/juggernaut.webp",
@@ -143,6 +152,7 @@ defmodule Galaxies.Repo.Migrations.InsertUnits do
         updated_at: now
       },
       %{
+        id: 201,
         name: "Solar Satellite",
         list_order: 10,
         image_src: "/images/units/solar-satellite.webp",
@@ -158,6 +168,7 @@ defmodule Galaxies.Repo.Migrations.InsertUnits do
         updated_at: now
       },
       %{
+        id: 202,
         name: "Crawler",
         list_order: 10,
         image_src: "/images/units/crawler.webp",
@@ -173,6 +184,7 @@ defmodule Galaxies.Repo.Migrations.InsertUnits do
         updated_at: now
       },
       %{
+        id: 301,
         name: "Spy Probe",
         list_order: 10,
         image_src: "/images/units/espionage-probe.webp",
@@ -188,6 +200,7 @@ defmodule Galaxies.Repo.Migrations.InsertUnits do
         updated_at: now
       },
       %{
+        id: 401,
         name: "Small Cargo Ship",
         list_order: 10,
         image_src: "/images/units/small-cargo.webp",
@@ -203,6 +216,7 @@ defmodule Galaxies.Repo.Migrations.InsertUnits do
         updated_at: now
       },
       %{
+        id: 402,
         name: "Large Cargo Ship",
         list_order: 10,
         image_src: "/images/units/large-cargo.webp",
@@ -218,6 +232,7 @@ defmodule Galaxies.Repo.Migrations.InsertUnits do
         updated_at: now
       },
       %{
+        id: 403,
         name: "Recycler",
         list_order: 10,
         image_src: "/images/units/large-cargo-v2.webp",
@@ -233,6 +248,7 @@ defmodule Galaxies.Repo.Migrations.InsertUnits do
         updated_at: now
       },
       %{
+        id: 404,
         name: "Colonizer",
         list_order: 10,
         image_src: "/images/units/colony.webp",
@@ -247,6 +263,7 @@ defmodule Galaxies.Repo.Migrations.InsertUnits do
         updated_at: now
       },
       %{
+        id: 405,
         name: "Asteroid Miner",
         list_order: 10,
         image_src: "/images/units/asteroid-miner.webp",
@@ -262,6 +279,7 @@ defmodule Galaxies.Repo.Migrations.InsertUnits do
         updated_at: now
       },
       %{
+        id: 501,
         name: "Missile Launcher",
         list_order: 10,
         image_src: "/images/units/missile-launcher.webp",
@@ -277,6 +295,7 @@ defmodule Galaxies.Repo.Migrations.InsertUnits do
         updated_at: now
       },
       %{
+        id: 502,
         name: "Light Laser Turret",
         list_order: 10,
         image_src: "/images/units/light-laser.webp",
@@ -292,6 +311,7 @@ defmodule Galaxies.Repo.Migrations.InsertUnits do
         updated_at: now
       },
       %{
+        id: 503,
         name: "Heavy Laser Turret",
         list_order: 10,
         image_src: "/images/units/heavy-laser.webp",
@@ -307,6 +327,7 @@ defmodule Galaxies.Repo.Migrations.InsertUnits do
         updated_at: now
       },
       %{
+        id: 504,
         name: "Ion Cannon",
         list_order: 10,
         image_src: "/images/units/ion-cannon.webp",
@@ -322,6 +343,7 @@ defmodule Galaxies.Repo.Migrations.InsertUnits do
         updated_at: now
       },
       %{
+        id: 505,
         name: "Gauss Cannon",
         list_order: 10,
         image_src: "/images/units/gauss-cannon.webp",
@@ -337,6 +359,7 @@ defmodule Galaxies.Repo.Migrations.InsertUnits do
         updated_at: now
       },
       %{
+        id: 506,
         name: "Plasma Cannon",
         list_order: 10,
         image_src: "/images/units/plasma-cannon.webp",
@@ -351,7 +374,40 @@ defmodule Galaxies.Repo.Migrations.InsertUnits do
         inserted_at: now,
         updated_at: now
       },
+      %{
+        id: 507,
+        name: "Small Shield Dome",
+        list_order: 10,
+        image_src: "/images/units/small-shield.webp",
+        short_description:
+          "The small shield dome covers the defense units and ships with a protective energy shield using a generator. This can absorb additional energy from the outside and is still permeable enough to let your own defenses fire.",
+        long_description:
+          "The small shield dome covers facilities and units with a protective energy shield using a generator. This can absorb additional energy from the outside and is still permeable enough to let own defense systems fire. Due to the high energy voltage required, only a limited number of shield domes can be built per planet. This amount can be increased by the ongoing progress of the empire.",
+        type: :defense,
+        weapon_points: 0,
+        shield_points: 2000,
+        hull_points: 4000,
+        inserted_at: now,
+        updated_at: now
+      },
+      %{
+        id: 508,
+        name: "Large Shield Dome",
+        list_order: 10,
+        image_src: "/images/units/large-shield.webp",
+        short_description:
+          "Further research into shield technologies has significantly improved the resilience of small shield domes. Large shield domes thus cover a much larger area of the planet, which means that its facilities and units can be protected much more efficiently.",
+        long_description:
+          "Further research into shield technologies has significantly improved the resilience of small shield domes. Large shield domes thus cover a much larger area of the planet, which means that more facilities and units can be protected more efficiently. Due to the high energy voltage required, only a limited number of shield domes can be built per planet. That number can be increased by ongoing progress of the empire.",
+        type: :defense,
+        weapon_points: 0,
+        shield_points: 10_000,
+        hull_points: 20_000,
+        inserted_at: now,
+        updated_at: now
+      },
       # %{
+      #   id: 509,
       #   name: "Fortress",
       #   image_src: "/images/units/.webp",
       #   short_description:
@@ -364,6 +420,7 @@ defmodule Galaxies.Repo.Migrations.InsertUnits do
       #   hull_points: 960_000
       # },
       # %{
+      #   id: 510,
       #   name: "Doom Cannon",
       #   image_src: "/images/units/.webp",
       #   short_description:
@@ -376,6 +433,7 @@ defmodule Galaxies.Repo.Migrations.InsertUnits do
       #   hull_points: 3_600_000
       # },
       # %{
+      #   id: 511,
       #   name: "Orbital Defense Platform",
       #   image_src: "/images/units/.webp",
       #   short_description:
@@ -387,37 +445,8 @@ defmodule Galaxies.Repo.Migrations.InsertUnits do
       #   shield_points: 1_000_000,
       #   hull_points: 22_400_000
       # },
-      %{
-        name: "Small Shield Dome",
-        list_order: 10,
-        image_src: "/images/units/small-shield.webp",
-        short_description:
-          "The small shield dome covers the defense units and ships with a protective energy shield using a generator. This can absorb additional energy from the outside and is still permeable enough to let your own defenses fire.",
-        long_description:
-          "The small shield dome covers facilities and units with a protective energy shield using a generator. This can absorb additional energy from the outside and is still permeable enough to let own defense systems fire. Due to the high energy voltage required, only a limited number of shield domes can be built per planet. This amount can be increased by the ongoing progress of the empire.",
-        type: :defense,
-        weapon_points: 0,
-        shield_points: 2000,
-        hull_points: 4000,
-        inserted_at: now,
-        updated_at: now
-      },
-      %{
-        name: "Large Shield Dome",
-        list_order: 10,
-        image_src: "/images/units/large-shield.webp",
-        short_description:
-          "Further research into shield technologies has significantly improved the resilience of small shield domes. Large shield domes thus cover a much larger area of the planet, which means that its facilities and units can be protected much more efficiently.",
-        long_description:
-          "Further research into shield technologies has significantly improved the resilience of small shield domes. Large shield domes thus cover a much larger area of the planet, which means that more facilities and units can be protected more efficiently. Due to the high energy voltage required, only a limited number of shield domes can be built per planet. That number can be increased by ongoing progress of the empire.",
-        type: :defense,
-        weapon_points: 0,
-        shield_points: 10_000,
-        hull_points: 20_000,
-        inserted_at: now,
-        updated_at: now
-      },
       # %{
+      #   id: 512,
       #   name: "Atmospheric Shield",
       #   image_src: "/images/units/.webp",
       #   short_description:
@@ -430,6 +459,7 @@ defmodule Galaxies.Repo.Migrations.InsertUnits do
       #   hull_points: 4_000_000
       # },
       %{
+        id: 601,
         name: "Interceptor Missile",
         list_order: 10,
         image_src: "/images/units/interceptor-missile.webp",
@@ -444,6 +474,7 @@ defmodule Galaxies.Repo.Migrations.InsertUnits do
         updated_at: now
       },
       %{
+        id: 602,
         name: "Interplanetary Missile",
         list_order: 10,
         image_src: "/images/units/interplanetary-missile.webp",