EF简单例子 Entity Framework

1 public class DBTestContext : DbContext
2     {
3         public IDbSet<User> Users { get; set; }
4         public IDbSet<Company> Companies { get; set; } 
5     }

1 public class User
2     {
3         public Guid Id { get; set; }
4         public string Name { get; set; }
5 
6         public Guid CompanyId { get; set; }
7         public Company Company { get; set; }
8 
9     }

 1 var ef = new DBTestContext();
 2 
 3             //var c = new Company()
 4             //{
 5             //    Id = Guid.NewGuid(),
 6             //    Name = "nx"
 7             //};
 8             //var u = new User()
 9             //{
10             //    Id = Guid.NewGuid(),
11             //    Name = "我呵呵哒",
12             //    CompanyId = c.Id,
13             //};
14             //ef.Users.Add(u);
15             //ef.Companies.Add(c);
16              
17             var df = from u in ef.Users
18                 where u.Company.Name == "nx"
19                 select u;
20             var fddf = df.ToList();
21              
22             var dfe = from u in ef.Users
23                 join c in ef.Companies on u.CompanyId equals c.Id
24                 where c.Name == "nx"
25                 select u;
26             var fesi = dfe.ToList();
27 
28             ef.SaveChanges();