GermanApp/GermanApp.csproj

@@ -10,7 +10,7 @@
     <PackageReference Include="Microsoft.AspNetCore.OpenApi" Version="9.0.16" />
     <PackageReference Include="Swashbuckle.AspNetCore" Version="6.5.0" />
     <PackageReference Include="Microsoft.EntityFrameworkCore" Version="9.0.0" />
-    <PackageReference Include="Microsoft.EntityFrameworkCore.Sqlite" Version="9.0.0" />
+    <PackageReference Include="Npgsql.EntityFrameworkCore.PostgreSQL" Version="9.0.0" />
     <PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="9.0.0">
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>

GermanApp/Program.cs

@@ -16,12 +16,12 @@ builder.Services.AddOpenApi();
 // INFRASTRUCTURE LAYER - Database & External Services
 // ============================================
 
-// Add DbContext with SQLite (can be changed to SQL Server, PostgreSQL, etc.)
+// Add DbContext with PostgreSQL
 builder.Services.AddDbContext<AppDbContext>(options =>
 {
-    // Using SQLite for development - configure in appsettings.json for production
-    options.UseSqlite(builder.Configuration.GetConnectionString("DefaultConnection") 
-        ?? "Data Source=germanapp.db");
+    // Using PostgreSQL for production and development
+    options.UseNpgsql(builder.Configuration.GetConnectionString("DefaultConnection") 
+        ?? "Host=localhost;Port=5432;Database=DeutschLernen;Username=postgres;Password=postgres");
     
     // Enable sensitive data logging in development
     if (builder.Environment.IsDevelopment())

GermanApp/appsettings.Development.json

@@ -1,8 +1,11 @@
 {
   "Logging": {
     "LogLevel": {
-      "Default": "Information",
-      "Microsoft.AspNetCore": "Warning"
-    }
+      "Default": "Debug",
+      "Microsoft.AspNetCore": "Information"
+    }
+  },
+  "ConnectionStrings": {
+    "DefaultConnection": "Host=localhost;Port=5432;Database=DeutschLernen;Username=postgres;Password=postgres"
   }
 }

GermanApp/appsettings.Production.json

@@ -0,0 +1,11 @@
+{
+  "Logging": {
+    "LogLevel": {
+      "Default": "Warning",
+      "Microsoft.AspNetCore": "Error"
+    }
+  },
+  "ConnectionStrings": {
+    "DefaultConnection": "Host=prod-db;Port=5432;Database=DeutschLernen;Username=postgres;Password=${DB_PASSWORD}"
+  }
+}

GermanApp/appsettings.Staging.json

@@ -0,0 +1,11 @@
+{
+  "Logging": {
+    "LogLevel": {
+      "Default": "Information",
+      "Microsoft.AspNetCore": "Warning"
+    }
+  },
+  "ConnectionStrings": {
+    "DefaultConnection": "Host=staging-db;Port=5432;Database=DeutschLernen;Username=postgres;Password=${DB_PASSWORD}"
+  }
+}

GermanApp/appsettings.json

@@ -5,5 +5,8 @@
       "Microsoft.AspNetCore": "Warning"
     }
   },
-  "AllowedHosts": "*"
+  "AllowedHosts": "*",
+  "ConnectionStrings": {
+    "DefaultConnection": "Host=localhost;Port=5432;Database=DeutschLernen;Username=postgres;Password=postgres"
+  }
 }