Add example function inserting relational data objects.

EntityFrameworkCore.Console/Program.cs

@@ -15,6 +15,64 @@ context.Database.EnsureCreated();
 // Rather than raise: "System.InvalidOperationException: Sequence contains no elements."
 // var firstCoach = await context.Coaches.FirstOrDefaultAsync();
 
+async Task InsertRelatedData()
+{
+  // Insert record with a Foreign Key.
+  var match = new Match
+  {
+    AwayTeamId = 1,
+    HomeTeamId = 2,
+    AwayTeamScore = 0,
+    HomeTeamScore = 0,
+    Date = new DateTime(2025, 6, 1),
+    TicketPrice = 20
+  };
+
+  await context.AddAsync(match);
+  await context.SaveChangesAsync();
+
+  // Insert Parent/Child
+  var team = new Team
+  {
+    Name = "Neo Istanbul",
+    Coach = new Coach
+      {
+        Name = "Gimbal Wizbouski"
+      }
+  };
+
+  await context.AddAsync(team);
+  await context.SaveChangesAsync();
+
+  // Insert Parent with Children.
+  var league = new League
+  {
+    Name = "Star League",
+    Teams = new List<Team>
+    {
+      new Team
+      {
+        Name = "Neo Cairo",
+        Coach = new Coach
+          {
+            Name = "Damon Pulsar"
+          }
+      },
+      new Team
+      {
+        Name = "Cyborgs",
+        Coach = new Coach
+          {
+            Name = "C-1"
+          }
+      }
+    }
+  };
+
+  await context.AddAsync(league);
+  await context.SaveChangesAsync();
+}
+
 async Task ExecuteDelete(string name)
 {
   // var coaches = await context.Coaches.Where(c => c.Name == name).ToListAsync();