Questions tagged [union-subclass]
10 questions
6
votes
1 answer
How to overcome the performance issues caused by the generated SQL of union-subclass in Hibernate
I am using Hibernate support for TABLE_PER_CLASS inheritance strategy. Functionality wise it works well. Whenever polymorphic query is issued Hibernate generates an SQL containing "union all" for my two concrete classes A & B. The generated SQL has…
user1392212
- 61
- 3
4
votes
2 answers
Why can't NHibernate use Identity in union-subclass Table per Concrete Class mapping?
Several sources state that NHibernate can not use identity with table per concrete class and union-subclasses. Is this true, and what is the exact reason behind this ?
Denis Biondic
- 7,943
- 5
- 48
- 79
4
votes
1 answer
Hibernate inheritance performance
I am using Hibernate 3 with a MySQL database (I tried with Hibernate 4 with no more success). I've implemented a table-per-concrete-class inheritance strategy (union-subclass).
It makes the job except for the polymorphic queries.
Hibernate…
yamichaud
- 41
- 2
3
votes
2 answers
How to map an abstract property with NHibernate union subclass?
Referring to Ayende's post here:
http://ayende.com/blog/3941/nhibernate-mapping-inheritance
I have a similar situation that can be reached by extending the union-subclass mapping of the above post a bit, by adding an abstract Name-property to the…
proge
- 31
- 3
2
votes
1 answer
Why doesn't NHibernate limit the sub query of a union subclass to a particular id?
Ayende in his post on NHibernate Mapping – Inheritance outlines how the various NHibernate inheritance strategies work. His explanation of union-subclass shows the SQL generated as using a sub query which unions the various tables. This subquery is…
ahsteele
- 26,243
- 28
- 134
- 248
1
vote
0 answers
Questions relevant to "Table per concrete class mapping" in hibernate technique
Am trying to understand inheritance types with hibernate.
when i look document there is "Table per concrete class" topic using union-subclass technique. Regarding this I am having some questions,
1). Why we need union-subclass mapping?
2). When…
Mohan
- 877
- 10
- 20
- 32
0
votes
1 answer
"NHibernate.ObjectNotFoundException: No row with the given identifier exists" on access to child collection
Little explanation: I have coupon series and coupons linked to the series.
Some coupons may ne activated, and they are stored in the separate table.
Here are my .hbm.xml files:
…
flam3
- 1,897
- 2
- 19
- 26
0
votes
1 answer
Object does not match target type.. Exception occured getter
I have a huge problem! I keep getting an exception when mapping an abstract class with multiple union-subclasses in nhibernate.
When I use only one union-subclass I dont get any error and everything works fine. When I use more subclasses this error…
Dominic Jordan
- 65
- 1
- 12
0
votes
1 answer
Nhibernate : Cannot use identity column key generation with mapping for:
I have three entity where Email & Sms entities is inherited of Message entity
public class Message
{
virtual public long Id { get; set; }
virtual public string Body { get; set; }
}
public class Email : Message
{
virtual public string…
Ehsan
- 3,431
- 8
- 50
- 70
0
votes
1 answer
Loading a collection of union-subclass entities polymorphically - column specified multiple times
Take the following entities:
public class Company : Entity
{
public virtual string Name { get; set; }
public virtual IList Employees { get; set; }
public Company()
{
Id = Guid.NewGuid();
Employees =…
Paul T Davies
- 2,527
- 2
- 22
- 39