我真的是EF的新手(使用EF core 2.1),到目前为止,我一直在学习大量教程,但是现在我开始尝试创建自己的数据库结构,并在尝试向数据库中添加值时迷失了方向:
private async Task<int> Insert()
{
var address = new Address { AddressLine1 = "1 any street", AddressLine2 = "", AddressLine3 = "", City = "Any city" };
using (var context = new BranchContext())
{
context.Addresses.AddAsync(address);//ERROR HERE
....
}
}
我得到了错误:
InvalidOperationException:属性“ Branch.Address”的类型为“ Address”,当前数据库提供程序不支持。可以使用“ [NotMapped]”属性或通过“ OnModelCreating”中的“ EntityTypeBuilder.Ignore”来更改属性CLR类型或忽略该属性。
我创建了以下课程:
public class Address
{
public int Id { get; set; }
public int Guid { get; set; }
public DateTime CreatedOn { get; set; }
public string Number { get; set; }
public string AddressLine1 { get; set; }
public string AddressLine2 { get; set; }
public string AddressLine3 { get; set; }
public string Town { get; set; }
public string City { get; set; }
public string Postcode1 { get; set; }
public string Postcode2 { get; set; }
public string Latitude { get; set; }
public string Longitude { get; set; }
}
public class Branch
{
public string Id { get; set; }
public string Name { get; set; }
public Address Address { get; set; }
public IEnumerable<EmployeeBranch> Employee { get; set; }
public bool IsMain { get; set; }
}
public class Employee
{
public int Id { get; set; }
public string Guid { get; set; }
public string EmailAddress { get; set; }
public JobTitle JobTitle { get; set; }
public DateTime DateOfBirth { get; set; }
public IEnumerable<EmployeeBranch> Branches { get; set; }
public Branch PrimaryBranch { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public string PreferredName { get; set; }
public Salutations Salutation { get; set; }
}
public enum Salutations
{
Mr = 1,
Mrs = 2,
Miss = 3,
Ms = 4
}
public class EmployeeBranch
{
public int BranchId { get; set; }
public Branch Branch { get; set; }
public int EmployeeId { get; set; }
public Employee Employee { get; set; }
}
public class JobTitle
{
public int Id { get; set; }
public string Guid { get; set; }
public string Name { get; set; }
}
然后我跑了
Add-Migration init
Update-Database
已创建以下内容:
为清楚起见,这是一个运行时错误,我已经查看了几个线程在尝试更新数据库here和here时遇到此错误,但是他们的讨论并没有指出我正确的观点。方向(也许我错过了明显的方向)。
我该如何解决?最好不要更改结构,尽管我很高兴有足够的理由这样做
答案 0 :(得分:6)
在引用导航属性而不是约束或类似条件内的映射属性的愚蠢情况下,也会出现此错误:
modelBuilder.Entity<TheEntity>().HasKey(ma => new { ma.SomeKey, ma.NavPropInsteadOfProp });
不幸的是,该错误还不够明显,但是暂时将错误的罪魁祸首注释掉将导致问题的根源。
答案 1 :(得分:0)
最后似乎是一个相当简单的答案,这个错误让我查看了我的类的结构并试图找出哪里出了问题。问题在于,在我的BranchContext
(我不考虑在问题中共享)中,我迷上了OnModelCreating
并根据需要设置了地址
错误
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.Entity<EmployeeBranch>()
.HasKey(s => new { s.BranchId, s.EmployeeId });
modelBuilder.Entity<Branch>()
.Property(s => s.Address).IsRequired();
modelBuilder.Entity<Branch>()
.Property(s => s.Name).IsRequired();
base.OnModelCreating(modelBuilder);
}
右
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.Entity<EmployeeBranch>()
.HasKey(s => new { s.BranchId, s.EmployeeId });
modelBuilder.Entity<Address>()
.Property(s => s.AddressLine1).IsRequired();
modelBuilder.Entity<Address>()
.Property(s => s.Postcode1).IsRequired();
modelBuilder.Entity<Address>()
.Property(s => s.Postcode2).IsRequired();
...the other required elements...
modelBuilder.Entity<Branch>()
.Property(s => s.Name).IsRequired();
base.OnModelCreating(modelBuilder);
}
答案 2 :(得分:0)
假设:目标是将Address
设为Branch
的必需属性
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.Entity<Branch>()
.HasOne(s => s.Address)
.WithMany()
.IsRequired();
}
您可以使用Fluent API来配置关系是必需的还是可选的