Add EF Core migration for Certificate entity with SQL Server support

api/CourseRegistration.API/CourseRegistration.API.csproj

@@ -8,6 +8,10 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.AspNetCore.OpenApi" Version="8.0.11" />
+    <PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="8.0.11">
+      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+      <PrivateAssets>all</PrivateAssets>
+    </PackageReference>
     <PackageReference Include="Microsoft.Extensions.Diagnostics.HealthChecks.EntityFrameworkCore" Version="8.0.11" />
     <PackageReference Include="Serilog.AspNetCore" Version="8.0.2" />
     <PackageReference Include="Swashbuckle.AspNetCore" Version="6.9.0" />

api/CourseRegistration.API/appsettings.json

@@ -1,4 +1,7 @@
 {
+  "ConnectionStrings": {
+    "DefaultConnection": "Server=(localdb)\\mssqllocaldb;Database=CourseRegistrationDb;Trusted_Connection=True;MultipleActiveResultSets=true"
+  },
   "Logging": {
     "LogLevel": {
       "Default": "Information",

api/CourseRegistration.Infrastructure/CourseRegistration.Infrastructure.csproj

@@ -6,7 +6,12 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.EntityFrameworkCore" Version="8.0.11" />
+    <PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="8.0.11">
+      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+      <PrivateAssets>all</PrivateAssets>
+    </PackageReference>
     <PackageReference Include="Microsoft.EntityFrameworkCore.InMemory" Version="8.0.11" />
+    <PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="8.0.11" />
   </ItemGroup>
 
   <PropertyGroup>

api/CourseRegistration.Infrastructure/Data/CourseRegistrationDbContext.cs

@@ -32,6 +32,11 @@ public CourseRegistrationDbContext(DbContextOptions<CourseRegistrationDbContext>
     /// </summary>
     public DbSet<Registration> Registrations { get; set; } = null!;
 
+    /// <summary>
+    /// Certificates DbSet
+    /// </summary>
+    public DbSet<Certificate> Certificates { get; set; } = null!;
+
     /// <summary>
     /// Configures the model relationships and constraints
     /// </summary>
@@ -108,6 +113,41 @@ protected override void OnModelCreating(ModelBuilder modelBuilder)
                   .HasForeignKey(r => r.CourseId)
                   .OnDelete(DeleteBehavior.Cascade);
         });
+
+        // Configure Certificate entity
+        modelBuilder.Entity<Certificate>(entity =>
+        {
+            entity.HasKey(c => c.CertificateId);
+            entity.Property(c => c.CertificateId).IsRequired();
+            entity.Property(c => c.StudentId).IsRequired();
+            entity.Property(c => c.CourseId).IsRequired();
+            entity.Property(c => c.IssueDate).IsRequired();
+            entity.Property(c => c.FinalGrade).IsRequired()
+                  .HasConversion<string>();
+            entity.Property(c => c.CertificateNumber).IsRequired().HasMaxLength(20);
+            entity.Property(c => c.Remarks).HasMaxLength(200);
+            entity.Property(c => c.DigitalSignature).HasMaxLength(100);
+
+            // Create index on CertificateNumber for quick lookups
+            entity.HasIndex(c => c.CertificateNumber).IsUnique();
+
+            // Create index on StudentId for efficient student certificate queries
+            entity.HasIndex(c => c.StudentId);
+
+            // Create index on CourseId for efficient course certificate queries
+            entity.HasIndex(c => c.CourseId);
+
+            // Configure relationships
+            entity.HasOne(c => c.Student)
+                  .WithMany()
+                  .HasForeignKey(c => c.StudentId)
+                  .OnDelete(DeleteBehavior.Restrict);
+
+            entity.HasOne(c => c.Course)
+                  .WithMany()
+                  .HasForeignKey(c => c.CourseId)
+                  .OnDelete(DeleteBehavior.Restrict);
+        });
     }
 
     /// <summary>

api/CourseRegistration.Infrastructure/Data/CourseRegistrationDbContextFactory.cs

@@ -0,0 +1,29 @@
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Design;
+
+namespace CourseRegistration.Infrastructure.Data;
+
+/// <summary>
+/// Design-time factory for CourseRegistrationDbContext to support EF Core migrations
+/// </summary>
+public class CourseRegistrationDbContextFactory : IDesignTimeDbContextFactory<CourseRegistrationDbContext>
+{
+    /// <summary>
+    /// Creates a new instance of CourseRegistrationDbContext for design-time operations
+    /// </summary>
+    public CourseRegistrationDbContext CreateDbContext(string[] args)
+    {
+        var optionsBuilder = new DbContextOptionsBuilder<CourseRegistrationDbContext>();
+
+        // Use SQL Server for migrations
+        // Connection string can be overridden via environment variable
+        var connectionString = Environment.GetEnvironmentVariable("MIGRATION_CONNECTION_STRING")
+            ?? "Server=localhost,1433;Database=CourseRegistrationDb;User Id=sa;Password=YourStrong!Passw0rd;TrustServerCertificate=True;MultipleActiveResultSets=true";
+
+        optionsBuilder.UseSqlServer(
+            connectionString,
+            options => options.MigrationsAssembly("CourseRegistration.Infrastructure"));
+
+        return new CourseRegistrationDbContext(optionsBuilder.Options);
+    }
+}