consider this:
company model:
public int id { get; set; }
public string name{ get; set; }
report model:
public int id { get; set; }
public string title { get; set; }
company2report (where one company can have many reports):
public int id { get; set; }
public int companyID { get; set; }
public int reportID{ get; set; }
public int sortorder{ get; set; }
where dbcontext is:
public DbSet<company> companies { get; set; }
public DbSet<report> reports { get; set; }
public DbSet<company2report> company2reports { get; set; }
if i wanted to join this in sql it is simply:
SELECT *
FROM companies as c
INNER JOIN company2reports as c2r ON c.id = c2r.companyID
INNER JOIN reports as r ON c2r.reportID = r.id
ORDER BY c2r.sortorder ASC
so here is my linq
var q = (from c in db.companies
join c2r in db.company2reports on c.id equals c2r.companyID
join r in db.hreports on c2r.reportID equals r.id
orderby c2r.sortorder
select new {
c.id, c.name,
r.id, r.title
});
which is all great except this fails
the sql which is generated looks like this:
SELECT c.id, c.name, r.id, r.title
FROM companies as c
INNER JOIN company2report as c2r ON c.id = c2r.companyID
INNER JOIN reports as r ON c2r.reportID = r.id
ORDER BY c2r.sortorder ASC
(see the first join on 3rd line) it generates COMPANY2REPORT rather than COMPANY2REPORTS
so then i tried adjusting the c2r model to look like this:
public int id { get; set; }
public int companyID { get; set; }
public int reportID{ get; set; }
public ICollection<report> reports { get; set; }
public int sortorder{ get; set; }
which made it worse
how do i get my models to work with my context and then to work with the join?
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UPDATE:
the answer supplied below is correct
but i wanted to clarify on a theoretical level:
it is because i was mixing my modes with relational db Fkeys vs. object association
in the end i chose to go with object association
i adjusted my models and code to look like this:
company model:
public class company
{
public int id { get; set; }
public string name { get; set; }
// navigation properties
public ICollection<report> reports { get; private set; }
}
report model:
public class report
{
public int id { get; set; }
public string title { get; set; }
public int companyId { get; set; }
public short sortorder { get; set; }
// navigation properties
public virtual company company { get; set; }
}
company2report DELETED
dbcontext:
public DbSet<company> companies { get; set; }
public DbSet<report> reports { get; set; }
//public DbSet<company2report> company2reports { get; set; }
linq:
var q = from c in db.companies
join r in db.reports on c.id equals r.companyId
where c.id == 4
orderby r.sortorder
select r;
If you want to create an one-to-many relationship between those two entities your model would be like this:
public class Company
{
public int Id { get; set; }
public string Name { get; set; }
public ICollection<Report> Reports { get; set; }
}
public class Report
{
public int Id { get; set; }
public string Title { get; set; }
public int? CompanyId { get; set; }
public Company Company { get; set; }
}
A company has many reports, each with one company. That relationship is represented as follows:
protected override void OnModelCreating(Modelbuilder modelBuilder)
{
modelBuilder.Entity<Company>()
.HasMany(c => c.Reports)
.WithOne(e => e.Company);
}
It can also be configured by starting with the other end of the relationship:
protected override void OnModelCreating(Modelbuilder modelBuilder)
{
modelBuilder.Entity<Report>()
.HasOne(e => e.Company)
.WithMany(c => c.Reports);
}
And dbContext
public class SampleContext : DbContext
{
public DbSet<Company> Companies { get; set; }
public DbSet<Report> Reports { get; set; }
}