Code first Approach

Hello Umain,

Please do below class and DBContext for your code first approach,

Classes:

using System;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;

public class Job
{
    [Key]
    public int JobId { get; set; }

    // Other job-related properties
    public string JobTitle { get; set; }
    public string Description { get; set; }

    // Navigation property for applications related to this job
    public virtual ICollection Applications { get; set; }
}

public class Employer
{
    [Key]
    public int EmployerId { get; set; }

    // Other employer-related properties
    public string CompanyName { get; set; }

    // Navigation property for applications submitted by this employer
    public virtual ICollection Applications { get; set; }
}

public class JobSeeker
{
    [Key]
    public int JobSeekerId { get; set; }

    // Other job seeker-related properties
    public string FullName { get; set; }

    // Navigation property for applications submitted by this job seeker
    public virtual ICollection Applications { get; set; }
}

public class Application
{
    [Key]
    public int ApplicationId { get; set; }

    // Foreign keys
    [ForeignKey("Job")]
    public int JobId { get; set; }

    [ForeignKey("Employer")]
    public int EmployerId { get; set; }

    [ForeignKey("JobSeeker")]
    public int JobSeekerId { get; set; }

    // Other application-related properties
    public string Resume { get; set; }

    [DataType(DataType.Date)]
    public DateTime ApplyDate { get; set; }

    // Possible statuses: Submitted, In Progress, Approved, Rejected, etc.
    public string Status { get; set; }

    // Navigation properties for related entities
    public virtual Job Job { get; set; }
    public virtual Employer Employer { get; set; }
    public virtual JobSeeker JobSeeker { get; set; }
}

DBContext :

public class YourDbContext : DbContext
{
    public DbSet JobApplications { get; set; }
    public DbSet Jobs { get; set; }
    public DbSet Employers { get; set; }
    public DbSet JobSeekers { get; set; }

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        // Configure relationships here
        modelBuilder.Entity()
            .HasRequired(ja => ja.Job)
            .WithMany(j => j.Applications)
            .HasForeignKey(ja => ja.JobId);

        modelBuilder.Entity()
            .HasRequired(ja => ja.Employer)
            .WithMany()
            .HasForeignKey(ja => ja.EmployerId);

        modelBuilder.Entity()
            .HasRequired(ja => ja.JobSeeker)
            .WithMany()
            .HasForeignKey(ja => ja.JobSeekerId);
    }
}

I am not sure what the various fields are for. In my understanding, an applicant and a candidate are the same thing. Perhaps you could call your main table a positions tabel. That is one possibility but you can use whatever term is meaningful for you but I think your table here is not a table of applications. A position might have one and only one job and employer and an associated list of candidates. A candidate (applicant) might have an ApplyDate and fields such as phone number. A position might have a list of skills and an applicant might also have a list of skills. It is important to begin with a good database design, You can use GenMyModel to make an impressive database design if you want.

https://app.genmymodel.com

Personally what I do is to create a sample database then I use generate code for it. In ohter words, I use Database First. It is easier for me to understand.

Instead of using byte for the Status field, consider using an enum

public enum ApplicationStatus
{
    Applied,
    UnderReview,
    Rejected,
    Accepted
}

public class Application
{
    // ... other properties

    public ApplicationStatus Status { get; set; }
}

int jobId = 123; // Replace with the actual job ID
var applicantsForJob = dbContext.Applications
    .Where(app => app.JobId == jobId)
    .Select(app => app.Candidate)
    .ToList();