继承不会对更新、删除和激活深度产生任何影响，只会影响到对象的查询方面。

Inheritance doesn't have any effect on updates, deletes, or activation depth, just the query aspect of objects.

youdao

换句话说，激活深度表示从根对象中标识的引用总数，db4o将在查询中遍历根对象并返回结果。

In other words, activation depth is a count of the number of references identified from the root object that db4o will traverse and return as part of a query.

youdao

在前面的例子中，当检索Ben时，默认的激活深度5足够用于检索Jessica，因为它只需要仅仅一个引用遍历。

In the previous case, when retrieving Ben, the default activation depth of 5 is sufficient to also retrieve Jessica because she only requires a single reference-traversal.

youdao