问题描述
|
我有这些表/类(示例):
table FirstTable (
Id INTEGER NOT NULL DEFAULT AUTOINCREMENT,Name VARCHAR(100) NOT NULL,Document VARCHAR(20) NOT NULL
)
table SecondTable (
Id INTEGER NOT NULL,Something VARCHAR(100) NULL,FOREIGN KEY (Id) REFERENCES FirstTable (Id)
)
public class FirstClass {
public string Name { get; set; }
public string Document { get; set; }
public SecondClass SecondClass { get; set; }
}
public class SecondClass {
public string Something { get; set; }
public FirstClass FirstClass { get; set; }
}
映射为:
public class FirstClassMap : ClassMap<FirtsClass> {
Table(\"FirstTable\");
Id(x => x.Id).GeneratedBy.Identity();
Map(x => x.Name);
Map(x => x.Document);
References(x => x.SecondClass,\"Id\").ForeignKey();
}
public class SecondClassMap : ClassMap<SecondClass> {
Table(\"SecondTable\");
Id(x => x.Id).GeneratedBy.Foreign(\"FirstClass\");
Max(x => x.something);
HasOne(x => x.FirstClass).PropertyRef(x => x.SecondClass).Cascade.SaveUpdate();
}
FirstClass可以具有(0,1)SecondClass,而SecondClass可以具有(1,1)FirstClass。
下面的代码返回错误“试图从空的一对一属性分配ID:SecondClass”
var test = new SecondClass();
test.FirstClass = new FirstClass();
test.something = \"New test\";
test.FirstClass.Name = \"My name\";
test.FirstClass.Document = \"My document\";
// ... commands to save.
解决方法
看来NH正在尝试先保存SecondClass,但无法从尚未保存的FirstClass抓取生成的ID。
尝试将
.Cascade.SaveUpdate()
移至FirstClassMap
中的References
声明,并在FirstClass上调用save命令。