I have an entity:
public class Foo
{
public virtual int Id;
public virtual IEnumberable<string> Bars;
}
And its mapping:
public class FooMapping : ClassMap<Foo>
{
public FooMapping()
{
Table("foo_table_in_database");
Id(x => x.Id, "Id");
HasMany(x => x.Bars)
.AsList()
.Table("bars_table_in_db")
.Element("BarId", m =>
{
m.Type<string>();
});
}
}
And an exception returned inside the entity insteaf of the expected result :(
base = {"could not initialize a collection: [Loya.Services.CouponsWeb.Promotion.LoyCouponCustomerGroups#2][SQL: SELECT loycouponc0_.Promotion_id as Promotion3_0_, loycouponc0_.LoyCustomerGroupId as LoyCusto1_0_, loycouponc0_.Index as Index0_ FROM loy_promotion__cu...
Database tables :
foo_table : *Id, other properties
bar_table : *FooId, *BarId
My aim is to get a List of BarId's (strings) in my Foo.
How do I map it properly?
I think you might need to specify the KeyColumn. I do something similar in one of my solutions and I would map the entities above as follows...
mapping.HasMany(x => x.Bars)
.Schema("Schema")
.Table("FooBars")
.Element("Bar")
.KeyColumn("FooID")
.ForeignKeyConstraintName("FK_FooBar_Foo")
.Not.Inverse()
.Cascade.All()
.Fetch.Select();
This will give a table called Schema.FooBars. It will have a FooID column (which is a foreign key back to the Foo table) and a Bar column which contains the value in your Bars collection.
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 couple of tables where the primary key in Bar is a foreign key to Foo i.e. a 1..0:1 relationship.
My mappings look like this:
class FooMapping : ClassMap<Foo>
{
public FooMapping()
{
Table("Foo");
Id(x => x.Id).Column("ID");
HasOne(x => x.Bar).Cascade.All();
}
}
class BarMapping : ClassMap<Bar>
{
public BarMapping()
{
Table("Bar");
Id(x => x.FooId).GeneratedBy.Foreign("Foo");
HasOne(x => x.Foo).Constrained();
}
}
The problem is that when I try to remove an instance of Bar by setting Foo.Bar = null and Bar.Foo = null, the record does not get deleted from the database.
What am I missing?
So basicly the problem is that you're using Cascade.All() in the mapping of Foo.
Instead of that you should be using Cascade.AllDeleteOrphan().
Cascade.All
when an object is save/update/delete, check the associations and save/update/delete all the objects found.
Cascade.AllDeleteOrphan
when an object is save/update/delete, check the associations and save/update/delete all the objects found. In additional to that, when an object is removed from the association and not associated with another object (orphaned), also delete it.
There is other dirty solution by making this relation with using HasMany and Cascade.AllDeleteOrphan.
class FooMapping : ClassMap<Foo>
{
public FooMapping()
{
Table("Foo");
Id(x => x.Id).Column("ID");
HasMany(x => x.Bar).KeyColumn("FooId").Cascade.AllDeleteOrphan();
}
}
I need a way to query in Nhibernate for items that have a Dictionary Property containing value.
Assume:
public class Item
{
public virtual IDictionary<int, string> DictionaryProperty {get; set;}
}
and mapping:
public ItemMap()
{
HasMany(x => x.DictionaryProperty)
.Access.ReadOnlyPropertyThroughCamelCaseField(Prefix.Underscore)
.AsMap<string>(
index => index.Column("IDNumber").Type<int>(),
element => element.Column("TextField").Type<string>().Length(666)
)
.Cascade.AllDeleteOrphan()
.Fetch.Join();
}
I want to query all Items that have a dictionary value of "SomeText". The following example in Linq fails:
session.Query<Item>().Where(r => r.DictionaryProperty.Any(g => g.Value == "SomeText"))
with error
cannot dereference scalar collection element: Value
So is there any way to achieve that in NHibernate? Linq is not an exclusive requirement but its preffered. Not that I'm not interested to query over dictionary keys that can be achieved using .ContainsKey . Φορ this is similar but not the same
Handling IDictionary<TValueType, TValueType> would usually bring more issues than advantages. One way, workaround, is to introduce a new object (I will call it MyWrapper) with properties Key and Value (just an example naming).
This way we have to 1) create new object (MyWrapper), 2) adjust the mapping and that's it. No other changes... so the original stuff (mapping, properties) will work, because we would use different (readonly) property for querying
public class MyWrapper
{
public virtual int Key { get; set; }
public virtual string Value { get; set; }
}
The Item now has
public class Item
{
// keep the existing for Insert/Updae
public virtual IDictionary<int, string> DictionaryProperty {get; set;}
// map it
private IList<MyWrapper> _properties = new List<MyWrapper>();
// publish it as readonly
public virtual IEnumerable<MyWrapper> Properties
{
get { return new ReadOnlyCollection<MyWrapper>(_properties); }
}
}
Now we will extend the mapping:
HasMany(x => x.Properties)
.Access.ReadOnlyPropertyThroughCamelCaseField(Prefix.Underscore)
.Component(c =>
{
c.Map(x => x.Key).Column("IDNumber")
c.Map(x => x.Value).Column("TextField")
})
...
;
And the Query, which will work as expected:
session
.Query<Item>()
.Where(r =>
r.Properties.Any(g => g.Value == "SomeText")
)
NOTE: From my experience, this workaround should not be workaround. It is preferred way. NHibernate supports lot of features, but working with Objects brings more profit
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.
this is my db:
tblGroups:
GroupID
GroupName
tblMembersInGroup
GroupID
MemberID
Rank
tblMembers
MemberID
Name
this is my Model:
class group
{
int groupid
string name
List<EnlistedMembers> myMembers;
}
class EnlistedMebmers
{
Member myMember;
int Rank;
}
class Member
{
int MemberID
string Name
}
I am not sure how to map this in FNH, as the Members class has no object that tells FNH who is the father.
I think the group mapping is obvious:
Table(tblGroup);
Id(x => x.groupid, "GroupID').GeneratedBy.Identity();
Map(x => x.name, "GroupName");
HasMany(x => x.myMembers).AsList().Inverse().Cascade.All();
What's next ?
how do I map enlistedmembers, with no identity object? and no group object ?
but with the extra rank data. the db has all the data, I need a way to create the classes right...
Thanks,
Dani
Is there a reason you need to map EnlistedMembers? If not, you could map Group.MyMembers like this:
HasManyToMany(z => z.MyMembers)
.AsList()
.Cascade.All()
.Table("tblMembersInGroup")
.ParentKeyColumn("GroupId")
.ChildKeyColumn("MemberId");
I suspect this may be a square peg for a round hole, but I'd look into SubClassing.
public class MemberMap : ClassMap<Member>
{
public MemberMap()
{
Table("tblMembers");
Id(x => x.MemberID);
Map(x => x.Name);
}
}
public class EnlistedMembersMap : SubclassMap<EnlistedMembers>
{
public EnlistedMembersMap()
{
Table("tblMembersInGroup");
Map(x => x.Rank);
}
}
You'll need to make EnlistedMembers inherit from Member. I'm also pretty sure it's going to bark about the composite key you have going in tblMembersInGroup. I don't have an answer for that... yet.