diff --git a/lib/membership/property.ex b/lib/membership/property.ex
index 433fc63..ed07ce2 100644
--- a/lib/membership/property.ex
+++ b/lib/membership/property.ex
@@ -16,8 +16,16 @@ defmodule Mv.Membership.Property do
   attributes do
     uuid_primary_key :id
 
-    attribute :value, :string,
-      description: "Speichert den Wert, Typ-Interpretation per property_type.typ"
+    attribute :value, :union,
+      constraints: [
+        storage: :type_and_value,
+        types: [
+          bool: [type: :boolean],
+          date: [type: :date],
+          int: [type: :integer],
+          string: [type: :string]
+        ]
+      ]
   end
 
   relationships do
@@ -25,4 +33,8 @@ defmodule Mv.Membership.Property do
 
     belongs_to :property_type, Mv.Membership.PropertyType
   end
+
+  calculations do
+    calculate :value_to_string, :string, expr(value[:value] <> "")
+  end
 end
diff --git a/lib/mv_web/member_live/form_component.ex b/lib/mv_web/member_live/form_component.ex
index b91d3c0..720e5c5 100644
--- a/lib/mv_web/member_live/form_component.ex
+++ b/lib/mv_web/member_live/form_component.ex
@@ -9,7 +9,11 @@ defmodule MvWeb.MemberLive.FormComponent do
       Enum.map(property_types, fn pt ->
         %{
           "property_type_id" => pt.id,
-          "value" => nil
+          "value" => %{
+            "type" => String.to_existing_atom(pt.type),
+            "value" => nil,
+            "_union_type" => pt.type
+          }
         }
       end)
 
@@ -34,7 +38,9 @@ defmodule MvWeb.MemberLive.FormComponent do
       >
         <.inputs_for :let={f_property} field={@form[:properties]}>
           <% type = Enum.find(@property_types, &(&1.id == f_property[:property_type_id].value)) %>
-          <.input field={f_property[:value]} label={type && type.name} />
+          <.inputs_for :let={value_form} field={f_property[:value]}>
+            <.input field={value_form[:value]} label={type && type.name} />
+          </.inputs_for>
           <input
             type="hidden"
             name={f_property[:property_type_id].name}
@@ -95,12 +101,27 @@ defmodule MvWeb.MemberLive.FormComponent do
           not Enum.member?(existing_properties, Map.get(i, "property_type_id"))
         end
 
+        params = %{
+          "properties" =>
+            Enum.map(member.properties, fn prop ->
+              %{
+                "property_type_id" => prop.property_type_id,
+                "value" => %{
+                  "_union_type" => Atom.to_string(prop.value.type),
+                  "type" => prop.value.type,
+                  "value" => prop.value.value
+                }
+              }
+            end)
+        }
+
         form =
           AshPhoenix.Form.for_update(
             member,
             :update_member,
             api: Mv.Membership,
             as: "member",
+            params: params,
             forms: [auto?: true]
           )
 
diff --git a/priv/repo/migrations/20250514151922_initial_migration.exs b/priv/repo/migrations/20250521234537_initial_migration.exs
similarity index 98%
rename from priv/repo/migrations/20250514151922_initial_migration.exs
rename to priv/repo/migrations/20250521234537_initial_migration.exs
index 64915c2..ddf8abe 100644
--- a/priv/repo/migrations/20250514151922_initial_migration.exs
+++ b/priv/repo/migrations/20250521234537_initial_migration.exs
@@ -21,7 +21,7 @@ defmodule Mv.Repo.Migrations.InitialMigration do
 
     create table(:properties, primary_key: false) do
       add :id, :uuid, null: false, default: fragment("gen_random_uuid()"), primary_key: true
-      add :value, :text
+      add :value, :map
       add :member_id, :uuid
       add :property_type_id, :uuid
     end
diff --git a/priv/resource_snapshots/repo/members/20250514151922.json b/priv/resource_snapshots/repo/members/20250521234537.json
similarity index 100%
rename from priv/resource_snapshots/repo/members/20250514151922.json
rename to priv/resource_snapshots/repo/members/20250521234537.json
diff --git a/priv/resource_snapshots/repo/properties/20250514151922.json b/priv/resource_snapshots/repo/properties/20250521234537.json
similarity index 95%
rename from priv/resource_snapshots/repo/properties/20250514151922.json
rename to priv/resource_snapshots/repo/properties/20250521234537.json
index 0707bcf..1fbee03 100644
--- a/priv/resource_snapshots/repo/properties/20250514151922.json
+++ b/priv/resource_snapshots/repo/properties/20250521234537.json
@@ -18,7 +18,7 @@
       "references": null,
       "size": null,
       "source": "value",
-      "type": "text"
+      "type": "map"
     },
     {
       "allow_nil?": true,
@@ -84,7 +84,7 @@
   "custom_indexes": [],
   "custom_statements": [],
   "has_create_action": true,
-  "hash": "F2A42A3427E0428637F465E4F357A3BE21B33231F94CF77B4843084128F6BDA5",
+  "hash": "4D127B8DA5051633CE92D4C94B1C3D76FCBD2EE992EF8318B977E5C2B8CF19E4",
   "identities": [],
   "multitenancy": {
     "attribute": null,
diff --git a/priv/resource_snapshots/repo/property_types/20250514151922.json b/priv/resource_snapshots/repo/property_types/20250521234537.json
similarity index 100%
rename from priv/resource_snapshots/repo/property_types/20250514151922.json
rename to priv/resource_snapshots/repo/property_types/20250521234537.json