Does any one can help me generate this ObjectPropertyRange using "The OWL API"??
<ObjectPropertyRange>
<Annotation>
<AnnotationProperty abbreviatedIRI="owl:backwardCompatibleWith"/>
<IRI>#ProgramLanguage</IRI>
</Annotation>
<ObjectProperty IRI="#specifiedBy"/>
<ObjectMaxCardinality cardinality="1">
<ObjectProperty IRI="#specifiedBy"/>
<Class IRI="#Grammars"/>
</ObjectMaxCardinality>
</ObjectPropertyRange>
This is how i got in the last 3 days....
<ObjectPropertyRange>
<ObjectProperty IRI="#has"/>
<ObjectMaxCardinality cardinality="1">
<ObjectProperty IRI="#has"/>
<Class IRI="#Quantity"/>
</ObjectMaxCardinality>
</ObjectPropertyRange>
From this code...
OWLClassExpression expression=df.getOWLObjectMaxCardinality(relations.max, objectProperty,range.getNNF());
OWLSubClassOfAxiom subClassOfAxiom=df.getOWLSubClassOfAxiom(df.getOWLClass(IRI.create(relations.class2)), expression);
OWLObjectPropertyRangeAxiom owlObjectPropertyRangeAxiom=df.getOWLObjectPropertyRangeAxiom(objectProperty,subClassOfAxiom.getSuperClass());
manager.addAxiom(new_ontology,owlObjectPropertyRangeAxiom);
To give a complete code snippet:
OWLDataFactory df = ...
OWLAnnotationProperty p=df.getOWLAnnotationProperty(IRI.create("urn:test#backwardCompatibleWith"));
OWLAnnotation ann=df.getOWLAnnotation(p, IRI.create("urn:test#languageDesign"));
OWLObjectProperty op=df.getOWLObjectProperty(IRI.create("urn:test#produces"));
OWLClass c = df.getOWLClass(IRI.create("urn:test#ProgramLanguage"));
OWLObjectPropertyRangeAxiom axiom=df.getOWLObjectPropertyRangeAxiom(op, c, Collections.singleton(ann));
At this point, add the axiom to your ontology and save in the preferred format. From the example, I'm guessing that's OWL/XML.
The question and this answer are available at https://github.com/owlcs/owlapi/issues/235 for further comments, discussions and any other activity that does not fit in StackOverflow format.
Regarding the mention of unsupported operations when adding annotations, note that all objects created by an OWLDataFactory are immutable. Annotations must be added when creating the objects, they cannot be added afterwards to already existing objects.
Related
I am using many classes per table mapping(subclasses with discriminator).
Is there a way to turn on second level caching for specific subclass only ?
NHibernate version is 3.1.0
If I put the tag <cache usage="read-only"/> right after the subclass tag, I get error at runtime(tells that cache is invalid child element for element subclass).
<class name="MyDomain.ParentClass, MyDomain" table="MyDomainClass">
<subclass name="MyDomain.SubClass, MyDomain" discriminator-value="SubClass">
</subclass>
</class>
NHibernate documentation (ch. 25.1) says:
Add <cache usage="read-write|nonstrict-read-write|read-only"/> (just after <class>) in the mapping of the entities you want to cache. It also works for collections (bag, list, map, set, ...).
So, sadly, no subclass.
Recently i had some performance problems in a SOAP webservice I wrote a while ago. I noticed I had a lot of queries going on and my hbm.xml mappings where full of lazy=false statements. I upgraded to NHibernate 3.0 and removed the lazy = false stuff and everything was a LOT faster....but now i am getting the following error:
System.InvalidOperationException: There was an error generating the XML document. ---> System.InvalidOperationException: The type UserProxy was not expected. Use the XmlInclude or SoapInclude attribute to specify types that are not known statically.
User is a class of which i removed the lazy=false property from the class tag like this:
<class name="User" table="Users" >
<id name="DatabaseID" unsaved-value="0" column="ID" type="integer" >
<generator class="native"/>
</id>
<property name="IsExpert"/>
.....more stuff here....
</class>
My webservice has a method like this (simplified a little..in real-life i use a repository-like pattern between the service and nhibernate):
[WebMethod]
public User GetUser(int userid)
{
session = GetCurrentSession();
return session.Load<User>(userid);
}
The webservice expects to serialize a user and NHibernate gives me a UserProxy (which is not a user exactly). How should I overcome this?
Don't return entities from the web method. Use a DTO.
Webservices cannot serialise proxies - session.Load(userId) will return a proxy. You should user session.Get(userId) .
I think the answers saying you should use DTOs are not helpful, there is a time and place for DTOs and sometimes you may just want to return the entity.
If the User has child proxy properties, I have a class for handling this situation. Basically it loops through all properties (using reflection, and recursively going through child objects and collections) and uses the NHibernate.IsInitialized to check whether the property is a proxy or the genuine article. If it is a proxy then it sets it to null, thus making it possible for WCF to serialise it.
I have a solution that was created with NHib 1.2 which we're upgrading to NHib 3.0.
Our hbm file has the following property:
<property name="ContentId" column="ContentId" access="field.camelcase-underscore" />
The class doesn't have a ContentId property. This was working fine in NHib 1.2 but now we're getting getting the following exception:
Could not compile the mapping document: XXXX.Core.Domain.Video.hbm.xml ---> NHibernate.MappingException: Problem trying to set property type by reflection ---> NHibernate.MappingException: class Core.Domain.Video, Core, Version=1.0.0.29283, Culture=neutral, PublicKeyToken=null not found while looking for property: ContentId ---> NHibernate.PropertyNotFoundException: Could not find the property 'ContentId', associated to the field '_contentId', in class 'Core.Domain.Video'.
Why would this stop working? Is it still supported in NHib 3?
We have many many properties like this that we might need to add.
NHibernate greatly improved its error messaging and diagnostics in NH2.X and again in NH3.X. You are telling NHibernate that you have a property and you want to map it via field access to a field named by _camelCase convention. You don't have a property named ContentId and NHibernate is letting you know that you lied to it. :)
Try updating your mapping to:
<property name="_contentId" column="ContentId" access="field" />
You will need to update any HQL or Criteria queries to use _contentId rather than ContentId. Another option would be to add a private ContentId property.
I'd like to provide information which helped me answer this question:
http://groups.google.com/group/nhusers/browse_thread/thread/e078734a221c3c0c/ec8b873b385d4426?lnk=gst&q=field+camelcase+underscore#ec8b873b385d4426
In this link Fabio explains the same problem you are having like this:
This mapping
<property name="PositiveValue" access="field.camelcase-underscore" />
mean: For my property named "PositiveValue" you (NH) have to access to
the field; to discover which is the associated field you (NH) have to
use the strategy "camelcase-underscore".
If there is no property you can't use the accessor with a specific
strategy.
Which struck me as a little odd because it meant adding dummy, unused properties, just to make the nhibernate3 compiler happy. The underlying functionality is the same.
Let's say my domain looks like this:
I have an object, Vehicle, that has an OdometerReading property.
An OdometerReading has the Miles & Date (when it was read).
I need to keep a history of all OdometerReadings for the Vehicle in the database, but don't want the entire odometer history to belong to the Vehicle object. What I would like is for the OdometerReading property map to the most recent OdometerReading entry out of the database.
I thought about mapping the whole collection of OdometerReadings to the Vehicle, and having a dynamic property called CurrentOdometerReading that would order them and return the latest one, but I don't need the whole collection under the Vehicle in my domain, and it seems like I would be getting more data out of the database than I need.
Is that possible with NHibernate? How would I map such a thing?
There are a few ways of doing this depending on what you want your domain model to look like. My preferred choice is to use a custom collection type, for example IOdometerReadingCollection, which you can add extra methods to. In this case it might be something like:
public interface IOdometerReadingCollection : IList<OdometerReading>
{
OdometerReading Latest { get; }
}
This way you can do:
OdometerReading reading = vehicle.OdometerReadings.Latest;
which I prefer to:
OdometerReading reading = vehicle.LatestOdometerReading;
There's lots of documentation about custom collections, which you can find with a simple google search.
If this approach isn't for you there are other options. You may be able to use a property with a formula (I'm not sure if that works with complex types?), or a regular NHibernate association where you'd have the key of the latest OdometerReading on your Vehicle mapping. As you also mentioned you could just load all the OdometerReadings, which depending on your use case might actually be fine.
I hope this helps, or at least points you in the right direction.
There is a "where" clause that you can put in your collection mapping. Check the reference documentation.
I would map the OdometerReading property as a component, then use a named query to ensure it's populated with the latest reading out of the database. (In this example, you'd have a sql-query with a name of "vehicle" that does the SQL to load the Vehicle columns along with the latest Odometer reading)
<class name="Vehicle">
<property name="Type" not-null="true"/>
<component name="OdometerReading">
<property name="Miles" />
<property name="Date" />
</component>
<loader query-ref="vehicle"/>
</class>
I've got two tables in my database: Articles and Tags
The Tags tables consist of ArticleID (foreign key) and a Tag (varchar).
Now I need to map an articles tags into a readonly collection on Article entity, either using IList Tags or ReadOnlyCollection Tags.
I've consulted the NHibernate reference material, but I can't seem to figure when to use Set, Bag and the other Nhibernate collections. I've seen examples using the ISet collection, but I really don't like to tie my entity classes to a NHibernate type.
How can I do the mapping in NHibernate?
edit: I ended up using a <bag> instead, as it doesn't require an index:
<bag name="Tags" table="Tag" access="nosetter.camelcase" lazy="false">
<key column="ArticleId" />
<element column="Tag" type="System.String" />
</bag>
The type of collection to use in your mapping depends on how you want to represent the collection in code. The settings map like so:
The <list> maps directly to an
IList.
The <map> maps directly to an IDictionary.
The <bag> maps to an IList. A does not completely comply
with the IList interface because the
Add() method is not guaranteed to
return the correct index. An object
can be added to a <bag> without
initializing the IList. Make sure to
either hide the IList from the
consumers of your API or make it
well documented.
The <set> maps to an Iesi.Collections.ISet. That
interface is part of the
Iesi.Collections assembly
distributed with NHibernate.
so if you want an IList to be returned, then you would use the <list> mapping. In your case, I'd probably map using the <list> mapping.