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how to seed data in many to many relation using ef

Zany Zebra answered on July 3, 2023 Popularity 3/10 Helpfulness 1/10

answer how to seed data in many to many relation using ef

how to seed data in many to many relation using ef

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public class Student
{
    public int StudentId { get; set; }
    public string Name { get; set; }

    public ICollection<Course> Courses { get; set; }
}

public class Course
{
    public int CourseId { get; set; }
    public string Title { get; set; }

    public ICollection<Student> Students { get; set; }
}

public class YourDbContext : DbContext
{
    public DbSet<Student> Students { get; set; }
    public DbSet<Course> Courses { get; set; }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Student>()
            .HasMany(s => s.Courses)
            .WithMany(c => c.Students)
            .UsingEntity(j => j.ToTable("StudentCourses"));


		SeedData(modelBuilder);
    }
}
private void SeedData(ModelBuilder modelBuilder)
    {
        // Add students
        var students = new List<Student>
        {
            new Student { Name = "John Doe" },
            new Student { Name = "Jane Smith" },
            new Student { Name = "Michael Johnson" }
        };
        modelBuilder.Entity<Student>().HasData(students);

        // Add courses
        var courses = new List<Course>
        {
            new Course { Title = "Mathematics" },
            new Course { Title = "History" },
            new Course { Title = "Science" }
        };
        modelBuilder.Entity<Course>().HasData(courses);

        // Add student-course relationships (seeding the junction table)
        var studentCourses = new List<object>
        {
            new { StudentsStudentId = 1, CoursesCourseId = 1 }, // John Doe takes Mathematics
            new { StudentsStudentId = 1, CoursesCourseId = 3 }, // John Doe takes Science
            new { StudentsStudentId = 2, CoursesCourseId = 2 }, // Jane Smith takes History
            new { StudentsStudentId = 3, CoursesCourseId = 1 }, // Michael Johnson takes Mathematics
            new { StudentsStudentId = 3, CoursesCourseId = 2 }, // Michael Johnson takes History
            new { StudentsStudentId = 3, CoursesCourseId = 3 }  // Michael Johnson takes Science
        };
        modelBuilder.Entity("StudentCourses").HasData(studentCourses);
    }

Popularity 3/10 Helpfulness 1/10 Language csharp

Source: chat.openai.com

Tags: c# many-to-many relation seed using

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Contributed on Jul 03 2023

Zany Zebra

0 Answers Avg Quality 2/10

how to seed data in many to many relation using ef

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