How to create mapping relationship using Fluent NHibernate - nhibernate

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.

Related

Entity Framework and using Fluent API for mapping two entities to another one

Scenario seems to be trivial and I'm really confused on what I'm doing wrong.
So, I have a Client class
public class Client
{
[Key]
public int ClientID { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public virtual Account Account { get; set; }
}
Employee class
public class Employee
{
[Key]
public int EmployeeID { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public virtual Account Account { get; set; }
}
and an Account class
public class Account
{
[Key]
public int AccountID { get; set; }
public string Login { get; set; }
public string Password { get; set; }
public virtual Employee Employee { get; set; }
public virtual Client Client { get; set; }
}
Both Client and Employee may have an Account or not ( online access is optional ). As database is not compatible with EF namingconvention I have to come up with Fluent API explicit mappings.
Both Client and Employee tables have "AccountID" column that I'm trying to use to build a relation.
modelBuilder.Entity<Client>()
.HasOptional(e => e.Account)
.WithRequired(a => a.Client)
.Map(m => m.MapKey("AccountID"));
modelBuilder.Entity<Employee>()
.HasOptional(e => e.Account)
.WithRequired(a => a.Employee)
.Map(m => m.MapKey("AccountID"));
but I get
Schema specified is not valid. Errors:
(15,6) : error 0019: Each property name in a type must be unique. Property name 'AccountID' was already defined.
(16,6) : error 0019: Each property name in a type must be unique. Property name 'AccountID' was already defined.
so, is there a way to fix this other than modification of the table/entity structure?
Turns out you don't need Fluent API in this case, what you need is to DataAnnotate your properties in Entities with InverseProperty attribute
[InverseProperty("AccountID")]
There is a great answer by Ladislav Mrnka in Entity Framework 4.1 InverseProperty Attribute question
However if anyone knows how to do that correctly with Fluent answers are highly appreciated

How do I use Fluent NHibernate ReferencesAny mapping?

I've read a lot about Fluent NHibernate's ReferencesAny but I haven't seen a complete example. I think I understand most of it, but there is one part I don't get. In the class mapping ReferencesAny(x => x.MemberName) is used to define the relationship to the one or more referenced classes. What is MemberName? How is it defined and how is it used to create the data in the database.
I have three tables, the records in one table can reference records in one of the other two tables. The first two are auto mapped, so the Id field is not specifically defined.
public class Household
{
public virtual string Name { get; set; }
public virtual IList<AddressXref> AddressXrefs { get; set; }
}
public class Client
{
public virtual string Name { get; set; }
public virtual IList<AddressXref> AddressXrefs { get; set; }
}
I'm not sure if the AddressXref table can be auto mapped. If so I need to find out how to do that too. For now I'll do it the conventional way with Fluent.
public class AddressXref
{
public virtual int id { get; set; }
public virtual string TableName { get; set; }
public virtual Int32 Table_id { get; set; }
public virtual string Street { get; set; }
public virtual string City { get; set; }
}
class AddressXrefMap : ClassMap<AddressXref>
{
public AddressXrefMap()
{
Table("AddressXref");
Id(x => x.id);
Map(x => x.TableName);
Map(x => x.Table_id);
Map(x => x.Street);
Map(x => x.City);
ReferencesAny(x => x.TableRef)
.AddMetaValue<Household>(typeof(Household).Name)
.AddMetaValue<Client>(typeof(Client).Name)
.EntityTypeColumn("TableName")
.EntityIdentifierColumn("Table_id")
.IdentityType<int>();
}
}
The part I need help with is how is the TableRef, referred to in ReferencesAny(), member of AddressXref defined in the class?
Also, how it is used in the code when creating data records? I image it will be similar to this:
Household Household = new Household();
Household.Name = "Household #1";
AddressXref AddrXref = new AddressXref();
AddrXref.Street1 = "123 Popular Street";
AddrXref.City = "MyTown";
AddrXref.TableRef = Household;
Session.SaveOrUpdate(AddrXref);
I love using Fluent with NHibernate, but I'm still amazed at the learning curve. :)
Thanks,
Russ
since both Household and Client don't share a base class other than object you have to declare it as this:
public class AddressXref
{
public virtual int Id { get; set; }
public virtual object TableRef { get; set; }
public virtual string Street { get; set; }
public virtual string City { get; set; }
}
and test it like this
if (addrXref.TableRef is HouseHold)
// it's a household

FluentNhibernate many-to-many and Inverse()

I have the following database tables defined:
Club: Id, Name
Member: Id, Name
ClubMember: ClubId, MemberId
I have the following entity Classes defined:
public class Club() {
public virtual int Id { get; set; }
public virtual string Name { get; set; }
public virtual IList<Member> Members { get; set; }
}
public class Member() {
public virtual int Id { get; set; }
public virtual string Name { get; set; }
public virtual IList<Club> Clubs { get; set; }
}
I have the following overrides defined:
public class MemberOverride : IAutoMappingOverride<Member>
{
public void Override(AutoMapping<Member> mapping_)
{
mapping_
.HasManyToMany(x_ => x_.Clubs)
.ParentKeyColumn("MemberId")
.ChildKeyColumn("ClubId")
.Cascade.All()
.Table("ClubMembers");
}
}
public class ClubOverride : IAutoMappingOverride<Club>
{
public void Override(AutoMapping<Club> mapping_)
{
mapping_
.HasManyToMany(x_ => x_.Members)
.ParentKeyColumn("ClubId")
.ChildKeyColumn("MemberId")
.Inverse()
.Table("ClubMembers");
}
}
I can see from my overrides that the Inverse on the ClubOverride means you cannot do the following
session.Save(club.Members.Add(member));
but this works:
session.Save(member.Clubs.Add(club);
But it doesn't make logical sense. I want to be able to save either the club with members or member with clubs.
Am I trying to do something impossible with FluentNhibernate?
TIA
Yes, you're right, that's not possible. But it's not a question of FluentNhibernate, NHibernate works like that.
Only one side is the owner of the relation and on charge of adding elements.
From official documentation:
Changes made only to the inverse end of the association are not persisted. This means that NHibernate has two representations in memory for every bidirectional association, one link from A to B and another link from B to A. This is easier to understand if you think about the .NET object model and how we create a many-to-many relationship in C#:
You can create add or remove methods on your entities that will help accomplish this:
public class Club() {
public virtual int Id { get; set; }
public virtual string Name { get; set; }
private IList<Member> members;
public virtual IEnumerable<Member> Members { get { return members.Select(x => x); } }
public Club() {
members = new List<Member>();
}
public virtual void AddMember(Member member){
if (members.Contains(member))
return;
members.Add(user);
member.AddClub(this);
}
public virtual void RemoveMember(Member member){
if (!members.Contains(member))
return;
members.Remove(member);
member.RemoveClub(this);
}
}

Fluent NHibernate map 2 identical classes to one table, first-lazy on, second-lazy off

So, I need to map my class to database table, but sometimes I need lazy loading to be on, sometimes to be off.
Example:
I made duplicates of these two classes described below, and I map them using FNH but with lazy loading on in original, and off in duplicate.
http://i.stack.imgur.com/goG30.png
Basically, I want to be able to get a team from DB that has all lists with TeamMembers fetched but those members should not have all their teams and everything else, just plain info about a TeamMember. Also when i get an TeamMember from DB, I want all its teams to contain only plain info's.
"http://i.stack.imgur.com/7OkyD.png" ->they don't allow new users to post pics or links.
So if I have only those two classes, then if lazy loading is turned on on any side, one of the situations explained before is not satisfied. If lazy is off on both sides I get a whole bunch of data that I don't need nor want.
At first original and duplicate had same names and were in different packages, but I got an exception that mapping was ambiguous. If there is a way for this to work, that would be ideal.
Is there a way to do this?
I couldn't find an answer so I changed name of duplicate to be NameOfOriginal+Lite.
Mapping was parsed but when I wanted to get a team from database, I get an exception:
{"ORA-00904: \"SUPERVIZ_\".\"TEAMMEMBERLITE_ID\": invalid identifier\n"}
So, apparently FNH reads a class name and ads an "_ID" and uses that as a ID for my duplicate class and that causes the problem. I tried with
.ParentKeyColumn("")
.ChildKeyColumn("")
but no success.
I hope I didn't confuse you too much :)
[DataContract]
public class Team
{
[DataMember]
public virtual int Team_id { get; private set; }
[DataMember]
public virtual String Name { get; set; }
[DataMember]
public virtual String Description { get; set; }
[DataMember]
public virtual TeamMember Deputy { get; set; }
[DataMember]
public virtual TeamMember Leader { get; set; }
[DataMember]
public virtual IList<TeamMember> TeamMembers { get; set; }
[DataMember]
public virtual IList<TeamMember> Supervizors { get; set; }
...
}
[DataContract]
public class TeamMember
{
[DataMember]
public virtual int TeamMember_id { get; set; }
[DataMember]
public virtual String First_name { get; set; }
[DataMember]
public virtual String Last_name { get; set; }
[DataMember]
public virtual String Sid { get; set; }
[DataMember]
public virtual IList<Team> SupevisingTeams { get; set; }
[DataMember]
public virtual IList<Team> LeaderInTeams { get; set; }
[DataMember]
public virtual IList<Team> DeputyInTeams { get; set; }
[DataMember]
public virtual IList<Team> MemberInTeams { get; set; }
...
}
You can map a class multiple times if you give the mapping an entity name. You will need to use ClassMap for this rather than auto mapping.
Using Fluent NHibernate:
public class Foo
{
public int Id { get; set; }
public string Name { get; set; }
}
public class FooMap1 : ClassMap<Foo>
{
public FooMap1()
{
Table("Foo");
EntityName("Foo");
Id(x => x.Id);
Map(x => x.Name);
}
}
public class FooMap2 : ClassMap<Foo>
{
public FooMap2()
{
Table("Foo");
EntityName("Bar");
Id(x => x.Id);
Map(x => x.Name);
}
}
You need to specify the entity name when building the query to make nhibernate use the correct mapping:
using (var session = _sessionFactory.GetCurrentSession())
{
return session.CreateCriteria("Bar")
.Add(Restrictions.Eq("Name", "Andrew"))
.List<Foo>();
}

Fluent NHibernate Automap Joined Sub-Class Setting the Key

When automapping a joined subclass in fluent nhibernate, I can't figure out how to give the joined subclass a primary key.
public class Address:Entity {
public virtual string Address1 { get; set; }
public virtual string Address2 { get; set; }
public virtual string City { get; set; }
public virtual string State { get; set; }
public virtual string Zip { get; set; }
public virtual string Phone { get; set; }
public virtual string Fax { get; set; }
public virtual IList<Location> Locations { get; set; }
}
public class Location:Address {
public virtual Address BillingAddress { get; set; }
public virtual string OfficeHours { get; set; }
public virtual string PatientAgeRestrictions { get; set; }
public virtual bool WheelchairAccess { get; set; }
public virtual string ContactPerson { get; set; }
public virtual string ContactEmail { get; set; }
public virtual string ContactPhone { get; set; }
public virtual string ContactFax { get; set; }
public virtual string TaxId { get; set; }
}
I want Location to have it's own id "location_ id" with it's own sequence. Then I want that mapped to address through an address_id column.
Right now it's generating the location with "addressid" as the primary key, which isn't what I want. How do I change this with the automapping?
I'm not sure you have a joined-subclass relationship. That is, by definition a joined subclass has the same ID as its parent class. For example, you might have a Person entity stored in your database for generic "people" information like name/age/etc and then an Employee subclass entity which is stored in a different table and holds data like position, salary, and dates of employment. So an Employee is a subtype of Person and to get the full "Employee-Person" object, you must join the two tables on their primary keys (e.g. SELECT * FROM Employee INNER JOIN Person ON Employee.Employee_id = Person.Person_id).
Are you sure about your relational model here? Is Location truly a subtype of Address? Inferring a bit from your property names, it seems to me that this is not what you intend. It seems like you probably have a many-to-many between an Address and an Organization (that is, there may be many "organizations" at the same address and an "organization" may have many addresses), with a "contact person" for the organization at a specific address. In which case you should map "organization", "contact", and another entity that defines the relationship between Address and "organization".