LINQ to SQL Association Mapping

linq-to-sql-associations.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data.Linq;
using System.Data.Linq.Mapping;

namespace MyNS{
    static void Main(string[] args) {
        JobsDataContext db = new JobsDataContext("Data Source=ServerName;Initial Catalog=MSDB;Integrated Security=SSPI;");
        Table<SysJobStep> primary_sysjobs = primary_db.SysJobSteps;  //error occurs here
        List<string> primary_sysjobstep_query = (from sjs in primary_sysjobs select sjs.SysJob.Name + "." + sjs.Name).ToList();
    }

    public class JobsDataContext : DataContext {

        public Table<SysJob> SysJobs;
        public Table<SysJobStep> SysJobSteps;

        public JobsDataContext(string connection) : base(connection) { }
    }

    [Table(Name = "SysJobs")]
    public class SysJob {

        private string _jobid;
        private string _name;

        private EntitySet<SysJobStep> _SysJobSteps;

        public SysJob() {
            this._SysJobSteps = new EntitySet<SysJobStep>();
        }

        [Column(Name = "job_id", Storage = "_jobid", CanBeNull = false,
            DbType = "uniqueidentifier not null")]
        public string JobId {
            get { return this._jobid; }
            set { this._jobid = value; }
        }

        [Column(Name = "name", Storage = "_name", CanBeNull = false)]
        public string Name {
            get { return this._name; }
            set { this._name = value; }
        }

        [Association(Storage = "_SysJobSteps", OtherKey = "JobId")]
        public EntitySet<SysJobStep> SysJobSteps {
            get { return this._SysJobSteps; }
            set { this._SysJobSteps.Assign(value); }
        }
    }

    [Table(Name = "SysJobSteps")]
    public class SysJobStep {
        private string _jobid;
        private int _stepid;
        private string _name;
        private EntityRef<SysJob> _job;

        public SysJobStep() {
            this._job = new EntityRef<SysJob>();
        }

        [Column(Name = "job_id", Storage = "_jobid", CanBeNull = false, DbType = "uniqueidentifier not null", IsDbGenerated = true)]
        public string JobId {
            get { return this._jobid; }
            set { this._jobid = value; }
        }

        [Association(Storage = "_job", ThisKey = "JobId")]
        public SysJob SysJob {
            get { return this._job.Entity; }
            set { this._job.Entity = value; }
        }

        [Column(Name = "step_id", Storage = "_stepid", CanBeNull = false, DbType = "int not null")]
        public int StepId {
            get { return this._stepid; }
            set { this._stepid = value; }
        }

        [Column(Name = "name", Storage = "_name", CanBeNull = false)]
        public string Name {
            get { return this._name; }
            set { this._name = value; }
        }
    }
}