I have a many to many relationship between
Portfolio and PortfolioTags
A portfolio Item can have many PortfolioTags
I am looking at the best way of saving tags to a portfolio item. My Nhibnerate maps are like so:
public class PortfolioMap : ClassMap<Portfolio> {
public PortfolioMap() {
Table("Portfolio");
LazyLoad();
Id(x => x.Id).GeneratedBy.Identity().Column("Id");
Map(x => x.AliasTitle).Column("AliasTitle").Not.Nullable();
Map(x => x.MetaDescription).Column("MetaDescription").Not.Nullable();
Map(x => x.Title).Column("Title").Not.Nullable();
Map(x => x.Client).Column("Client").Not.Nullable();
Map(x => x.Summary).Column("Summary").Not.Nullable();
Map(x => x.Url).Column("Url");
Map(x => x.MainImage).Column("MainImage");
Map(x => x.TitleAlt).Column("TitleAlt");
Map(x => x.Description).Column("Description").Not.Nullable();
HasMany(x => x.PortfolioImage).KeyColumn("PortfolioId").Inverse();
HasMany(x => x.PortfolioTag).KeyColumn("PortfolioId").Cascade.All().Table("PortfolioTag").Inverse();
}
}
public class PortfoliotagMap : ClassMap<Portfoliotag> {
public PortfoliotagMap() {
Table("PortfolioTag");
LazyLoad();
Id(x => x.Id).GeneratedBy.Identity().Column("Id");
References(x => x.Portfolio).Column("PortfolioId");
References(x => x.Tag).Column("TagId");
}
}
public class TagMap : ClassMap<Tag>
{
public TagMap() {
Table("Tag");
LazyLoad();
Id(x => x.TagId).GeneratedBy.Identity().Column("TagId");
Map(x => x.TagVal).Column("Tag").Not.Nullable();
HasManyToMany(x => x.Portfolio).Table("PortfolioTag").ParentKeyColumn("TagId").ChildKeyColumn("PortfolioId").Inverse();
}
}
In my portfolio controller I am first trying to save my tags that do not exist. I tried using SaveOrUpdate on a tag repository. However as the ids are different multiple save of tags occurs at this point.
I thought about the following steps but it seems long winded:
1) getting all tags:
var tags = _tagRepository.GetAll();
2) Iterating over the tags from the item to save and seeing if they exist in the database. If so I would need to get the tag and associate with the portfolio item. If not i would need to save the tag one by one and then associate with the portfolio item.
var tags = _tagRepository.GetAll();
foreach (var tagInPortfolio in StringUtilities.SplitToList(model.Tags, new[] { ',' }))
{
// tag does not exist so save it
if (tags.Any(i => i.TagVal == tagInPortfolio))
{
_tagRepository.SaveOrUpdate(new Tag {TagVal = tagInPortfolio});
}
}
3) I then need to delete any relationships i.e. tags to portfolio items that dont exist.
4) Finally need to add the tag to to the portfolioTag. I would need to get all the tags again and then associate:
portfolio.PortfolioTag.Add(new Portfoliotag {Portfolio = portfolio, Tag = tag});
_portfolioRepository.UpdateCommit(portfolio);
This seems to long winded. Can anyone explain the most simplest way of doing this please.
I have looked at saveandcommit on tags but i get multiple inserts because of ids being different. Do I need to delete all existing tag relationships also as this seems to much logic for something simple.
Create now works with a commit -
public void CreateCommit(T entity)
{
using (ITransaction transaction = Session.BeginTransaction())
{
Session.Save(entity);
transaction.Commit();
}
}
However using the below and the above maps still meant duplicates where occurring in the tag table. So if one portfolio record added a tag like abc and another portfolio record added a tag abc i need the join table to reference the same record in the tag and not create another instance of abc. Do i need to do a lookup on the tag table to avoid this
public void UpdateCommit(T entity)
{
using (ITransaction transaction = Session.BeginTransaction())
{
Session.Update(entity);
transaction.Commit();
}
}
If I understood correctly, I think you misunderstood the many-to-many mapping. If you really have a relationship like this between the Portifolio and the Tag classes, you should not map the PortfolioTag table.
In a simple many-to-many relationship the table used to connect the other two main tables should have only the foreign keys from the two tables (that would also be a composite key of this intermediate table). In this case, the PortfolioTag table would have only two columns: PortfolioId and TagId, that would be not only foreign keys for the Portfolio and Tag tables, but also the primary key of this intermediate table.
In this case, your Portfolio class should have a list of Tags instead of a list of PortfolioTag, and the Tag class a list of Portfolios. And you should map the Portfolio and the Tag like this (with no need of mapping the intermediate table):
public class PortfolioMap : ClassMap<Portfolio> {
public PortfolioMap() {
Table("Portfolio");
LazyLoad();
Id(x => x.Id).GeneratedBy.Identity().Column("Id");
//
// Code intentionally omitted for clarity
//
HasManyToMany(x => x.Tags)
.Table("PortfolioTag")
.ParentKeyColumn("PortfolioId")
.ChildKeyColumn("TagId")
.LazyLoad()
.Cascade.SaveUpdate();
}
}
public class TagMap : ClassMap<Tag> {
public TagMap() {
Table("Tag");
LazyLoad();
Id(x => x.Id).GeneratedBy.Identity().Column("Id");
Map(x => x.TagVal).Column("Tag").Not.Nullable();
HasManyToMany(x => x.Portfolios)
.Table("PortfolioTag")
.ParentKeyColumn("TagId")
.ChildKeyColumn("PortfolioId")
.Inverse();
}
}
You will also have to save the Portfolio inside the context of a transaction for the intermediate table to be populated, like bellow:
using (var trans = Session.BeginTransaction()) {
try {
Session.SaveOrUpdate(obj);
trans.Commit();
} catch {
trans.Rollback();
throw;
}
}
//or like this (with TransactionScope)
using (var trans = new TransactionScope()) {
Session.SaveOrUpdate(obj);
trans.Complete();
}
With this approach, you would also be excused of the need to iterate through the Tags list to save each one. You would be able to just save the Portfolio and everything should be fine.
P.S.: I tested this code with FluentNHibernate v1.4.0.0 and NHibernate v3.3.1.4000.
Related
I have the following use case:
public class Object {
long Id
...
ISet<Tags> tags
}
public class Tag : IEquatable<Tag> {
string Label;
}
Object is an Aggregate Root and Tag a Value Object.
Both are stored in 2 different tables:
CREATE TABLE incident(id bigint, ...)
CREATE Table tag (object_id bigint References object(id), label varchar,...)
I'm trying to create the ClassMap using FluentNhibernate, which works well for object but I couldn't find a way to map it with Tag
public ObjectsMapping()
{
Id(x => x.Id).GeneratedBy.Assigned();
Version(x => x.ObjectVersion).Column("object_version");
HasMany(x => x.Tags).Inverse().Cascade.All().KeyColumn("object_id");
}
public TagsMapping()
{
CompositeId().KeyProperty(x => x.Label).KeyProperty(x => x.CreationTimestamp);
Map(x => x.Label);
Map(x => x.CreationTimestamp);
}
Any idea how to map that an entity that has a oneToMany relation with a ValueObject from another table ?
Basically I'm looking for an equivalient of Set() in NHibernate
Thank you
I found the solution:
In ObjectMapping:
HasMany(x => x.Tags).Component(x => { x.Map(k => k.Label); }).Table("tag");
I'm trying to map a very basic parent-child relation with Fluent NHibernate.
However, when analyzing the SQL, only the parent-INSERT statement is created.
The situation is a simple class with a list of other classes. No relation back to the parent is needed. The children needs to be inserted/updated when the parent is inserted/updated.
var room = new Room();
room.Name = "Room1";
room.Courses.Add(new Course(){ Name = "Course1"});
room.Courses.Add(new Course(){ Name = "Course2"});
using (var session = sessionFactory.OpenStatelessSession())
{
using (var transaction = session.BeginTransaction())
{
session.Insert(room);
transaction.Commit();
}
}
The mapping looks like this.
public class RoomMapping : ClassMap<Room>
{
public RoomMapping()
{
Table("Rooms");
Id(x => x.Id)
.GeneratedBy.SeqHiLo("seq_rooms", "1000");
Map(x => x.Name);
HasMany(x => x.Courses)
.Cascade.All();
}
}
public class CourseMap : ClassMap<Course>
{
public CourseMap()
{
Table("Courses");
Id(x => x.Id)
.GeneratedBy.SeqHiLo("seq_courses", "1000");
Map(x => x.Name);
}
}
I already played with multiple options of the HasMany, however non with any success.
Sorry people. I just found it out.
I'm working in a Stateless session. So no relationships are managed ;)
I'm a new in nHibernate help me to save an object and his connections in the base.
I've got the base with two tables:
person (idPerson, firstName, secondName, idService
service (idService, name)
The table service has 3 positions (gold, silver, brilliant)
The Mapping:
public class PersonMap:ClassMap<Person>
{
public PersonMap()
{
Id(x => x.id);
Map(x => x.firstName);
Map(x => x.lastName);
Map(x => x.status);
References(x => x.serviceType).Column("idServiceType");
Table("Person");
}
}
public class ServiceMap : ClassMap<ServiceType>
{
public ServiceMap()
{
Id(x => x.id);
Map(x => x.serviceName);
Table("Service");
}
}
I use the next method in Repository for saving:
public void Saves(Person entity)
{
using (var session = hibernateHelp.OpenSession())
{
using (var transaction = session.BeginTransaction())
{
ServiceRepository srp = new ServiceRepository();
NHibernateUtil.Initialize(entity.service);
session.Save(entity);
transaction.Commit();
}
}
}
I recive the date (firstName="My" lastName="Go" status=TRUE, serviceType="gold"), then I create a Person:
Person df=new Person{
firstName="My",
lastName="Go",
status=true,
serviceType=new ServiceType{serviceName="gold"}
};
When I send it to the Repository method Save(see above) the mapping is working and saving the new object in the table person and create the new note in the table service.
I need't to create the new note in the table service since it containts one. How to make the saver's method in order to save the link to the table server, but not create the new one???
I appreciate any links and suggestions.
Person newPerson = new Person
{
FirstName = "My",
LastName = "Go",
Status = true,
serviceType = session.Load<ServiceType>(idOfGold) // returns the service if loaded or a proxy representing it which is enough to save the reference
// or
serviceType = session.Query<ServiceType>().Where(st.name == "gold").Single()
};
session.Save(newPerson);
having a little trouble with a mapping for the following table setup currently:
Shop
[1] [1]
/ \
[n] [n]
Category-[m]---[n]-Article
The behaviour should be the following :
1 - when deleting a shop, all Articles and Categories Should be deleted
2 - when deleting a Category, related Articles should be unassigned but not deleted
3 - when deleting an Article, related Categories should be unassigned but not deleted
Here's the current mapping:
public class ShopMap: ClassMap<Shop>
{
public ShopMap()
{
this.Table("shop");
Id(x => x.Id).Column("id").GeneratedBy.Native();
Map(x => x.Name).Column("name");
HasMany(x => x.Categories).Cascade.AllDeleteOrphan;
HasMany(x => x.Articles).Cascade.AllDeleteOrphan;
}
}
public class CategoryMap: ClassMap<Category>
{
public CategoryMap()
{
this.Table("category");
Id(x => x.Id).Column("id").GeneratedBy.Native();
Map(x => x.Name).Column("name");
References(x => x.Shop);
HasManyToMany(x => x.Articles).Cascade.AllDeleteOrphan()
.Table("article_category")
.ChildKeyColumn("article_id")
.ParentKeyColumn("category_id")
.Inverse();
}
}
public class ArticleMap: ClassMap<Article>
{
public ArticleMap()
{
this.Table("article");
Id(x => x.Id).Column("id").GeneratedBy.Native();
Map(x => x.Name).Column("name");
References(x => x.Shop);
HasManyToMany(x => x.Categories).Cascade.All()
.Table("article_category")
.ParentKeyColumn("article_id")
.ChildKeyColumn("category_id");
}
}
When deleting a Category (Session.Delete()), NH tries to delete the related Articles as well. Changing the Cascade-Mode to SaveUpdate will fix this, but will leave the entries in the link table *article_category*. Summing up : Cascade.SaveUpdate is too lazy, Cascade.All is too eager.
I tried everything that came to my mind in the mappings, but couldn't find a correct way to map this (rather simple schema).
Any ideas on how to (fluently) map this are greatly appreciated!
Thanks in advance
Sebi
The entries are left in the link table because Category.Articles is defined as the inverse side of the relationship. You need to remove the Category from Article.Categories before deleting it in order for the link record to be removed.
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?
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.
That mappings looks right for table-per-subclass mapping, assuming that SpecialUser extends User. My guess is that it's a bug.