[英]unsupported class hierarchy change in Db4o
I have: 我有:
static class Db4o...
and: 和:
class Db4oBase... // which uses Db4o class
where I can: 我可以在哪里:
class Customer : Db4oBase
{
public Customer(string name)
{
}
}
so that I can: 这样我可以:
Customer customer = new Customer("Acbel Polytech Philippines");
customer.store(); //something like that
It worked, until sometime in my development, the code below suddenly bugged down: 它一直有效,直到我开发某个时候,下面的代码突然出现错误:
class Db4o
{
.
.
.
public static IObjectSet Retrieve(object obj)
{
IObjectSet objectSet = null;
objectSet = container.Ext().QueryByExample(obj); // This part of the code
// throws a unsupported
// class hierarchy.
return objectSet;
}
}
The QueryByExample instruction throws an unsupported class hierarchy. QueryByExample指令将引发不受支持的类层次结构。 Does anybody know what should I do? 有人知道我该怎么办吗?
It happened when you: 当您:
yes, Hierarchy (inheritance) is supported but change it is not so simple to apply on existent file. 是的,支持层次结构(继承),但要更改其应用于现有文件并不是那么简单。
Somehow your class hierachy has changed -- which is not directly supported by db4o . 您的类层次结构以某种方式发生了变化-db4o 不直接支持 。 What ever happend, you have the following options (from db4o docs): 无论发生什么,您都有以下选项(来自db4o docs):
Okay this is what I did to remove the exception. 好的,这就是我删除异常的方法。 I just created another clean database file. 我刚刚创建了另一个干净的数据库文件。 But I haven't find out what is the root cause that led to that error. 但是我还没有找出导致该错误的根本原因。 No time for that yet. 现在还没有时间。 But it removed the "Unsupported class hierarchy change" exception. 但是,它删除了“不支持的类层次结构更改”异常。 So if any of you encountered this you might want to try doing what I've done but if you know the root cause, please post it here as an answer. 因此,如果您遇到任何此问题,您可能想尝试做我所做的事情,但是如果您知道根本原因,请在此处张贴它作为答案。 Thanks. 谢谢。
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.