问题
I have a set of fluent object mappings that looks like this:
public class UserMap : ClassMap<User>
{
public UserMap()
{
Map(x => x.Id);
Map(x => x.Status);
}
}
public class SpecialUserMap : SubClassMap<SpecialUser>
{
public SpecialUserMap()
{
Map(x => x.Property);
}
}
public class DirectoryMap : ClassMap<Directory>
{
public DirectoryMap
{
Map(x => x.Id);
HasMany(x => x.SpecialUsers).Where("Status = 0");
}
}
User is a join table, which SpecialUser joins against to get things like status. However, when I try to reference a SpecialUser in Directory's SpecialUsers collection, I get an error of "Undefined column 'Status'", as in the generated SQL, NHibernate tries to grab the Status column from the SpecialUser table, and not the User table. Is there a way to explicitly tell NHibernate which table to get the Status column in the DirectoryMapping?
回答1:
The Status property of a User / SpecialUser needs to map onto a single column in the database. You can't have it coming sometimes from User and sometimes from SpecialUser.
As a workaround, you could add a SpecialUserStatus property to SpecialUser, and then you could query on that easily.
回答2:
That mappings looks right for table-per-subclass mapping, assuming that SpecialUser extends User. My guess is that it's a bug.
来源:https://stackoverflow.com/questions/1903988/nhibernate-explicit-fluent-column-mapping