Initial: AI code exploration exercise

src/Before.Console/Program.cs

@@ -0,0 +1,83 @@
+using Before;
+
+// ---------------------------------------------------------------------------
+// Before.Console — a straight-line demo of the ActiveRecord-style pattern.
+//
+// The console app sets DbBase.Context (the shared singleton) once at startup,
+// then creates client/order entities, saves them through the context, and
+// queries back using the ActiveRecord entry points:
+//   • Client.FindByName(name) — no context argument: rides the
+//     DbBase.Context singleton
+//   • listing via DbBase.Context!.Tracked
+// ---------------------------------------------------------------------------
+
+var ctx = new DbContext();
+DbBase.Context = ctx;
+
+// ----- seed data ----------------------------------------------------------
+var jane = new Client { Name = "Jane Doe" };
+var bob  = new Client { Name = "Bob Smith" };
+
+jane.Orders.Add(new Order { Description = "Design consultation" });
+jane.Orders.Add(new Order { Description = "Website redesign" });
+
+bob.Orders.Add(new Order { Description = "Monthly retainer" });
+
+// Orders need to be attached too so they get IDs:
+ctx.Attach(jane.Orders[0]);
+ctx.Attach(jane.Orders[1]);
+ctx.Attach(bob.Orders[0]);
+
+ctx.Attach(jane);
+ctx.Attach(bob);
+ctx.Save();
+
+// ----- list all clients ---------------------------------------------------
+Console.WriteLine("=== All Clients ===");
+foreach (var client in DbBase.Context!.Tracked.OfType<Client>())
+{
+    Console.WriteLine($"{client.Name} [{client.Id}]");
+    foreach (var order in client.Orders)
+        Console.WriteLine($"  - order [{order.Id}]: {order.Description}");
+}
+
+// ----- find by name -------------------------------------------------------
+Console.WriteLine("\n=== Find by Name (null-returning) ===");
+// No context argument: FindByName falls back to the DbBase.Context singleton.
+var found = Client.FindByName("Jane Doe");
+if (found is not null)
+{
+    Console.WriteLine($"Found: {found.Name} [{found.Id}]");
+    Console.WriteLine($"  Orders: {found.Orders.Count}");
+}
+else
+{
+    Console.WriteLine("Not found.");
+}
+
+// ----- find by name (throwing variant) ------------------------------------
+Console.WriteLine("\n=== Find by Name Required (throws instead of returning null) ===");
+try
+{
+    var required = Client.FindByNameRequired("Jane Doe");
+    Console.WriteLine($"Found: {required.Name} [{required.Id}]");
+    Console.WriteLine($"  Orders: {required.Orders.Count}");
+}
+catch (ObjectNotFoundException ex)
+{
+    Console.WriteLine($"Not found: {ex.Message}");
+}
+
+// Show the contrast with a non-existent name:
+Console.WriteLine("\n=== Miss: null-returning vs throwing ===");
+var missNull = Client.FindByName("Nobody Here");
+Console.WriteLine($"FindByName(\"Nobody Here\"): {(missNull == null ? "null" : missNull.Name)}");
+try
+{
+    Client.FindByNameRequired("Nobody Here");
+}
+catch (ObjectNotFoundException ex)
+{
+    var msg = ex.Message.ReplaceLineEndings(" ").Trim();
+    Console.WriteLine($"FindByNameRequired(\"Nobody Here\"): throws - {msg}");
+}