using Microsoft.EntityFrameworkCore; namespace BlazorApp1; public class AppDbContext : DbContext { public AppDbContext(DbContextOptions<AppDbContext> options) : base(options) { } protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder) { optionsBuilder.UseNpgsql("Host=localhost;Database=testdb;Username=postgres;Password=12345"); } protected override void OnModelCreating(ModelBuilder modelBuilder) { modelBuilder.Entity<Student>() .HasOne<Grade>(s => s.Grade) .WithMany(g => g.Students) .HasForeignKey(s => s.CurrentGradeId); } public DbSet<Student> Students { get; set; } public DbSet<Grade> Grades { get; set; } } public class Student { public int Id { get; set; } public string Name { get; set; } public int CurrentGradeId { get; set; } public Grade Grade { get; set; } } public class Grade { public int GradeId { get; set; } public string GradeName { get; set; } public string Section { get; set; } public ICollection<Student> Students { get; set; } }
References
https://www.entityframeworktutorial.net/efcore/configure-one-to-many-relationship-using-fluent-api-in-ef-core.aspx
https://docs.microsoft.com/en-us/ef/core/modeling/relationships?tabs=fluent-api%2Cfluent-api-simple-key%2Csimple-key