级联保存 - StaleObjectStateException：行已被另一个事务更新或删除

Question

更新 NHibernate 版本时遇到问题。当前版本是 3.3.1.4000，正在尝试更新到 4。更新单元测试后，用级联保存失败：

NHibernate.StaleObjectStateException: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect): [NHibernateTests.TestMappings.ProductLine#cdcaf08d-4831-4882-84b8-14de91581d2e]

映射:

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" assembly="NHibernateTests" namespace="NHibernateTests.TestMappings">
    <class name="Product" lazy="false" table="UserTest">
        <id name="Id">
            <generator class="guid"></generator>
        </id>

        <version name="Version" column="Version" unsaved-value="0"/>
        <property name="Name" not-null="false"></property>
        <property name="IsDeleted"></property>

        <bag name="ProductLines" table="ProductLine" inverse="true" cascade="all" lazy="true" where="IsDeleted=0" >
            <cache usage="nonstrict-read-write" />
            <key column="UserId" />
            <one-to-many class="ProductLine"  />
        </bag>
    </class>
</hibernate-mapping>


<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" assembly="NHibernateTests" namespace="NHibernateTests.TestMappings">
    <class name="ProductLine" where="IsDeleted=0" lazy="false">
        <cache usage="nonstrict-read-write" />
        <id name="Id">
            <generator class="guid"></generator>
        </id>

        <version name="Version" column="Version" unsaved-value="0"/>
        <property name="IsDeleted"></property>

        <many-to-one name="Product" class="Product" column="UserId" not-null="true" lazy="proxy"></many-to-one>

    </class>
</hibernate-mapping>

类:

public class Product
{
    public Guid Id { get; set; }
    public int Version { get; set; }
    public bool IsDeleted { get; set; }

    public string Name { get; set; }
    public bool IsActive { get; set; }
    public IList<ProductLine> ProductLines { get; private set; }

    public Product()
    {
        ProductLines = new List<ProductLine>();
    }
}

public class ProductLine
{
    public Guid Id { get; set; }
    public int Version { get; set; }
    public bool IsDeleted { get; set; }

    public Product Product { get; set; }
}

测试：

[TestMethod]
public void CascadeSaveTest()
{
    var product = new Product
    {
        Id = Guid.NewGuid(),
        Name = "aaa",
        IsActive = true
    };
    var productLine = new ProductLine
    {
        Id = Guid.NewGuid(),
        Product = product,
    };
    product.ProductLines.Add(productLine);

    using (var connection = new RepositoryConnection())
    {
        using (var repositories = new Repository<Product>(connection))
        {
            repositories.Create(product);
            //the below just calls the Session.Transaction.Commit();
            connection.Commit();   //NH3.3.1.400 passes, NH4 fails
        }
    }
}

提前感谢您的想法。

Answer 1

好吧，我想我现在已经明白是什么导致了 NH 4 的错误。如果我是对的，那是一个有点人为的案例，导致这种行为很难被认定为错误。

在您的示例中，产品系列通过 bag 映射。 bag 可以包含重复项，这需要 Product 和 ProductLine 之间的中间值 table。（类似于带有 UserId (ProductId) 列和 ProductLineId 列的 ProductProductLine table。）

您已将此中间 table 设置为 ProductLine table。我怀疑对 db 的提交导致 NHibernate 插入产品，然后是产品线，然后尝试通过在 ProductLine table 中再次插入来插入关系。（您可以通过在您的数据库上分析 SQL 查询来检查这一点。）

事情有点混乱，因为 doc 状态（强调是我的）：

table (optional - defaults to property name) the name of the collection table (not used for one-to-many associations)

但是，如何遵守 collection 中允许重复的 bag 语义？来自同一文档：

A bag is an unordered, unindexed collection which may contain the same element multiple times.

无论如何，在您的示例中，您确实应该将 one-to-many 映射到 set，如 doc.

所示

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" assembly="NHibernateTests" namespace="NHibernateTests.TestMappings">
    <class name="Product" lazy="false" table="UserTest">
        <id name="Id">
            <generator class="guid"></generator>
        </id>

        <version name="Version" column="Version" unsaved-value="0"/>
        <property name="Name" not-null="false"></property>
        <property name="IsDeleted"></property>

        <set name="ProductLines" inverse="true" cascade="all" lazy="true" where="IsDeleted=0" >
            <cache usage="nonstrict-read-write" />
            <key column="UserId" />
            <one-to-many class="ProductLine"  />
        </set>
    </class>
</hibernate-mapping>

并更改您的 collection 类型以使用 .Net fx 4 System.Collections.Generic.ISet<T>。

public ISet<ProductLine> ProductLines { get; private set; }

public Product()
{
    ProductLines = new HashSet<ProductLine>();
}

如果这导致您的问题消失，则意味着 NH 4 中 bag 处理方式发生了一些变化。但是我们是否应该将此变化视为一个错误？不确定，因为在这种情况下使用 bag 不适合我。

Answer 2

进一步深入研究发现 NHibernate4 在与 Cascade 相关时无法识别它是新实体还是已经存在的实体。对于有问题的场景，它正在为 ProductLine 调用 SQL Update，而不是 Create。

它适用于以下更改，但我对 NHibernate 版本之间的此类更改感到非常困惑。

更改为 ProductLine 映射

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" assembly="NHibernateTests" namespace="NHibernateTests.TestMappings">
    <class name="ProductLine" where="IsDeleted=0" lazy="false">
        <cache usage="nonstrict-read-write" />
        <!-- here comes the updated line -->
        <id name="Id" type="guid" unsaved-value="00000000-0000-0000-0000-000000000000">
            <generator class="guid"></generator>
        </id>

        <version name="Version" column="Version" unsaved-value="0"/>
        <property name="IsDeleted"></property>

        <many-to-one name="Product" class="Product" column="UserId" not-null="true" lazy="proxy"></many-to-one>

    </class>
</hibernate-mapping>

更改测试方法

[TestMethod]
public void CascadeSaveTest()
{
    var product = new Product
    {
        Id = Guid.NewGuid(),
        Name = "aaa",
        IsActive = true
    };
    var productLine = new ProductLine
    {
        Id = Guid.Empty,            //The updated line
        Product = product,
    };
    product.ProductLines.Add(productLine);

    using (var connection = new RepositoryConnection())
    {
        using (var repositories = new Repository<Product>(connection))
        {
            repositories.Create(product);
            connection.Commit();
        }
    }
}

级联保存 - StaleObjectStateException：行已被另一个事务更新或删除

Cascade Save - StaleObjectStateException: Row was updated or deleted by another transaction

nhibernate

nhibernate-mapping