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nhibernate - NHibernate 在查询中使用错误的键，抛出 ObjectNotFoundByUniqueKeyException

问题描述

ObjectNotFoundByUniqueKeyException使用 NHibernate 5.2，当我执行以下操作时，由于使用无效键执行错误查询，我得到了一个：

var session = sessionFactory.OpenSession();

var employee = new Employee(){
    UserId = "joe",
    Certifications = new List<Certification>()
};

employee.Certifications.Add(new Certification() { Employee = employee});

var id = session.Save(employee);
session.Flush();
session.Clear();
var emp = session.Get<Employee>(id);

foreach(var e in emp.Certifications)
{
    Console.WriteLine(e.Id);
}

执行的查询

NHibernate: INSERT INTO Employee (UserId) VALUES (@p0); select SCOPE_IDENTITY();@p0 = 'joe' [Type: String (4000:0:0)]
NHibernate: INSERT INTO Certification (UserId) VALUES (@p0); select SCOPE_IDENTITY();@p0 = 'joe' [Type: String (4000:0:0)]
NHibernate: SELECT userquery_0_.Id as id1_0_0_, userquery_0_.UserId as userid2_0_0_ FROM Employee userquery_0_ WHERE userquery_0_.Id=@p0;@p0 = 1 [Type: Int32 (0:0:0)]
NHibernate: SELECT certificat0_.UserId as userid2_1_1_, certificat0_.Id as id1_1_1_, certificat0_.Id as id1_1_0_, certificat0_.UserId as userid2_1_0_ FROM Certification certificat0_ WHERE certificat0_.UserId=@p0;@p0 = 1 [Type: Int32 (0:0:0)]
NHibernate: SELECT userquery_0_.Id as id1_0_0_, userquery_0_.UserId as userid2_0_0_ FROM Employee userquery_0_ WHERE userquery_0_.UserId=@p0;@p0 = '1' [Type: String (4000:0:0)]

我期待@p0 = 'joe'在最后两个查询中，而不是1and '1'。任何人都可以看到下面可以解释这种行为的映射问题吗？

类/映射

public class Employee
{
    public virtual int Id { get; set; }
    public virtual string UserId { get; set; }
    public virtual ICollection<Certification> Certifications { get; set; }
}

public class EmployeeMap : ClassMap<Employee>
{
    public EmployeeMap()
    {
        Table("Employee");
        Id(x => x.Id);
        Map(x => x.UserId);
        HasMany(x => x.Certifications)
            .KeyColumn("UserId")
            .Cascade.All();
    }
}

public class Certification
{
    public virtual int Id { get; set; }
    public virtual Employee Employee { get; set; }
}

public class CertificationMap : ClassMap<Certification>
{
    public CertificationMap()
    {
        Table("Certification");
        Id(x => x.Id);
        References(x => x.Employee)
            .Column("UserId")
            .PropertyRef(x => x.UserId);
    }
}

标签： nhibernatefluent-nhibernate

解决方案

Collection没有使用 Employee 的主键，而是另一个属性 - PropertyRef。我们必须像多对一一样通知一对多映射

    HasMany(x => x.Certifications)
        .KeyColumn("UserId")
        .Cascade.All()
        // use property, not the ID, when searching for my items
       .PropertyRef("UserId")
       ;

缺少此映射的事实导致在 NHibernate 加载集合时使用 ID（魔术 1）

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