We are working on a domain where the requirement is that a MemberAgreement varies based on Network and State combination. MemberAgreement has a Template which can be shared by multiple States for a Network.
The way we are modelling the Entities is
public class MemberAgreement
{
public Network Network { get; protected set; }
public List<State> States { get; protected set; }
public Template Template {get; protected set; }
}
The tables are designed as:
Agreement
---------
Id
NetworkId
StateId
TemplateId
In this table Agreement, NetworkId and TemplateId can repeat for different StateIds.
Now, how do I map this in Fluent NHibernate? We have One to Many relation between Network and State and combination of these two has Many to Many relation with Template.
Help is appreciated.
PC
The table structure as is will force you to change your MemberAgreement object definition. Every row (unique by ID) is referencing exactly one ReferenceType:
public class MemberAgreement
{
public virtual Network Network { get; protected set; }
// public List<State> States { get; protected set; }
public virtual State State { get; protected set; }
public virtual Template Template {get; protected set; }
}
Having this, your mapping will be simplified References(x => x.State). But more issues will come in your business layer, where you have to work with collection: IList<MemberAgreement>.
Other option is to use 6.9. Ternary Associations. Extracted and applied on a Network:
public class Network
{
...
public virtual IDictionary<State, Template> StateTemplates { get; set; }
}
<map name="States" table="Agreement" >
<key column="NetworkId" />
<index-many-to-many column="StateId" class="State" />
<many-to-many column="TempalteId" class="Template" />
</map>
and in Fluent like this :
HasMany(x => x.StateTemplates)
.KeyColumn("NetworkId")
.AsMap<State>("StateId")
.AsTernaryAssociation("TemplateId");
Related
I'm currently working on and ASP.NET MVC application in which I have a User entity like follows:
public class User
{
public virtual int Id { get; protected set; }
public virtual string Name { get; protected set; }
public virtual string Role { get; protected set; }
public virtual Location Location { get; protected set; }
}
Where location is just as straightforward:
public class Location
{
public virtual string Id { get; protected set; }
public virtual string Building { get; protected set; }
public virtual string City { get; protected set; }
public virtual string Region { get; protected set; }
}
My complication arises because I want to populate the User from Active Directory and not the database. Additionally, several classes persisted to the database reference a user as a property. I've got an ADUserRepository for retrieval, but I don't know how to integrate these Users into my object graph when the rest is managed by NHibernate.
Is there a way for NHibernate to persist just an id for a User without it being a foreign key to a Users table? Can I map it as a component to accomplish this? I've also looked at implementing IUserType to make the translation. That way it would map to a simple field and ADUserRepository could be put in the chain to resolve the stored Id. Or am I trying to hack something that's not really feasible? This is my first time around with NHibernate so I appreciate any insight or solutions you can give. Thanks.
Update
It appears my best solution on this will be to map the User with an IUserType and inject (preferably with StructureMap) a service for populating the object before its returned. Framed in that light there are a couple of questions here that deal with the topic mostly suggesting the need for a custom ByteCodeProvider. Will I still need to do this in order for IUserType to take a parameterized constructor or do the comments here: NHibernate.ByteCode.LinFu.dll For NHibernate 3.2 make a difference?
using a Usertype to convert user to id and back
public class SomeClass
{
public virtual string Id { get; protected set; }
public virtual User User { get; protected set; }
}
// in FluentMapping (you have to translate if you want to use mapping by code)
public SomeClassMap()
{
Map(x => x.User).Column("user_id").CustomType<UserType>();
}
public class UserType : IUserType
{
void NullSafeSet(...)
{
NHibernateUtil.Int32.NullSafeSet(cmd, ((User)value).Id, index);
}
void NullSafeGet(...)
{
int id = (int)NHibernateUtil.Int32.NullSafeGet(cmd, ((User)value).Id, index);
var userrepository = GetItFromSomeWhere();
return userrepository.FindById(id);
}
}
Fluent Nhibernate Many to Many association to multiple classes
We use Nhibernate and up to now we have been able use the auto mapping. But I think this is about to change.
We have a Code class that has a many to many relation with several other classes.
I’m thinking something along these lines:
public class Code
{
public virtual Guid Id { get; set; }
public virtual ICollection<CodeUsage> Usage { get; set; }
}
class CodeUsage
{
public virtual Guid Id { get; set; }
public virtual Code Code { get; set; }
// Class, [Property,] Id for "ANY" mapping to A & B
}
class A
{
public virtual Guid Id { get; set; }
public virtual ICollection<CodeUsage> Codes { get; set; }
}
class B
{
public virtual Guid Id { get; set; }
public virtual ICollection<CodeUsage> Codes { get; set; }
}
Many to Many will lead to the creation of a linking table, in the linking table their needs come a mapping to the classes using codes. In the documentation it is referred to as a “Any” mapping.
But I have no idea how get fluent to create one.
Thoughts anyone? or even better: a solution <);o)}{
You can't map <many-to-any> in Fluent NHibernate - it's not supported.
I think it may be a good reason to move to mapping-by-code, that supports it well.
I've searched a lot after a solution for this, but the only thing that came out was a solution with FH-mapping instead of XML-mappng.
I'm working with a QR-scanning system where two users can scan eachother. If one user shoots an other user their id got filled in in this table.
So the two FK's will be unique together. 1-2. 2-1, 1-3
So my domain actually contains this two classes:
public class SnappedUsers
{
public virtual User Shooter {get; set;}
public virtual User Target { get; set; }
public virtual DateTime SnapDate { get; set; }
}
public class User : Entity
{
public virtual string DisplayName { get; set; }
public virtual string EmailAddress { get; set; }
public virtual string Password { get; set; }
public virtual string ProfilePicUrl { get; set; }
public virtual int Money { get; set; }
public virtual DateTime RegistrationDate { get; set; }
}
The table SnappedUsers should contain two foreign keys from the User table.
(it's not necessary that i put an Shooter ISet and an Target ISet to my User class.)
How do i actually have to map these things with XML-mapping? I don't see a solution myself for now.
Thx in advance
<composite-id>
<key-many-to-one name="Shooter" column="shooter_Id" >
<key-many-to-one name="Target" column="target_Id" />
</composite-id>
How can I map one-to-many relationship with
User to Address,
Customer to Address,
Agency to Address and
store in a single Address Table using Fluent NHibernate
public class User
{
public virtual int Id { get; set; }
public virtual string Name { get; set; }
public virtual IList<Address> Address { get; set; }
}
public class Customer
{
public virtual int Id { get; set; }
public virtual string Name { get; set; }
public virtual IList<Address> Address { get; set; }
}
public class Agency
{
public virtual int Id { get; set; }
public virtual string Name { get; set; }
public virtual IList<Address> Address { get; set; }
}
public class Address
{
public virtual int Id { get; set; }
public virtual string Address1 { get; set; }
public virtual string Address2 { get; set; }
public virtual string City { get; set; }
public virtual string State { get; set; }
}
I think you'll need to store your relations independently to connect addresses and users/customers/agencies if you want to be able to use the same address for all types. This involves introducing a new table that only stores ID pairs, and making that the storage location for your relationship.
You can map collections as many-to-many and use the table method to name your link table. Your mapping would look something like:
public UserMap : ClassMap<User> {
Id (u => u.Id);
Map (u => u.Name);
HasManyToMany (u => u.Addresses).Table ("UsersXAddresses");
}
You'll need a similar link table for customers and agencies.
In the constructor for your mapping class, map the link using the HasMany method. HasMany will create a one-to-many relationship. HasManyToMany will create a many-to-many relationship.
For example: HasMany(x => x.Address).LazyLoad();
This will create a one-to-many relationship between the User class and the Address class.
For the many-to-many, you will also need to specify the table name and if you so desire, the left and right side table mappings.
For example: HasManyToMany(x => x.Address).Table("AddressToUser").ParentKeyColumn("AddressId").ChildKeyColumn("UserId").LazyLoad();
If you decide that you want to set up a distinction between a UserAddress and an AgencyAddress (where these are sub-classes of Address) - you can use the DiscriminateSubClassesOnColumn method in the AddressMap class so the FNH knows to create an extra column in order to determine which type of object to create.
For example: DiscriminateSubClassesOnColumn("Type").AlwaysSelectWithValue();
You should be able to use FNH Automapping to map these classes "as is".
It will handle all the relationships in your object model.
I believe it will put all the addresses in a single Address table as you desire, but can't say for sure.
Recently I came across a strange behavior in Automapping of Fluent NHibernate. I have the following class structure (some properties cut off for the sake of brewity).
public class UserGroup
{
public virtual UserGroup ParentGroup { get; set; }
public virtual UserGroupMember Manager { get; protected set; }
public virtual ISet<UserGroupMember> Members { get; protected set; }
}
and
public class UserGroupMember : BaseEntity
{
public virtual User User { get; set; }
public virtual UserGroup Group { get; set; }
}
The mapping for UserGroup:
public class UserGroupMap : IAutoMappingOverride<UserGroup>
{
public void Override(AutoMapping<UserGroup> mapping)
{
mapping.HasMany(el => el.Members)
.Cascade
.AllDeleteOrphan().Inverse().LazyLoad();
}
}
The automapping creates two column (both of which are foreign keys) in the UserGroupMember table to reflect the relation between UserGroup and UserGroupMembers. I've found out that the generated mapping contains wrong column (as seen below):
<set cascade="all-delete-orphan" inverse="true" lazy="true" name="Members" mutable="true">
<key>
<column name="Parent_Id" />
</key>
<one-to-many class="Groups.Data.UserGroupMember, Server, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" />
</set>
which results in wrong queries:
While insert in UserGroupMember - Group_Id is used (which is right), not using Parent_Id
While select in UserGroupMember - Parent_Id is used
Group_Id is the column in UserGroupMember mapping file which reflects the Group property in UserGroupMember.
I tried to modify the mapping adding .KeyColumn("Group_Id") and it is solves the problem. But is there any way to make Fluent NHibernate 'think the right way'?
This is from memory, as I don't have test code ready.
When using bidirectional many-to-many, you sometimes have to help FHN figure columns names, if they're not "alike" on both sides.
For example this should map correcly
public class User
{
public IList<Group> Groups { get; set; }
}
public class Group
{
public IList<User> Users { get; set; }
}
While this would not
public class User
{
public IList<Group> BelongsTo { get; set; }
}
public class Group
{
public IList<User> Contains { get; set; }
}
As a rule of thumb, if automapping (with or without conventions) doesn't generate right columns names, especially for non trivial cases, do not hesitate to put an override to set those column names manually.