I'm using Nhibernate 3.3.1 and I need to ensure that none of my string columns would have lengths smaller than 15 i.e.
I'm trying to check it no AfterMapProperty/BeforeMapProperty events of ModelMapper, but as I know Length property is private of PropertyMapper class or some base class of it.
I'm tryign to avoid to use Reflection to access private property to get Length and check it.
Can you help me?
You can use the check attribute to achieve this.. In your mapping file you need to define something like this:
<property name="Foo" type="string">
<column name="foo" check="DATALENGTH(foo) > 15"/>
</property>
This will create a check constraint.. I am not too sure about the DATALENGTH method but you can confirm that..
Refer section 20.1.1 of NH docs here: http://nhibernate.info/doc/nh/en/index.html
Related
Am using EclipseLink 2.4.2 with derby database. I have an Entity class which has a String array. Now, i need to map this array to a separate table 'MY_ARGS' such that index must be mapped to one column 'ARRAY_INDEX' and the value (at index) must be mapped to another column 'ARG'.
In hibernate we have 'array' element through which we can do this. Like below :
<array name="args" table="MY_ARGS" cascade="all">
<key column="PARENT_ID"/>
<list-index column="ARRAY_INDEX" />
<element type="string" column="ARG" length="16384" />
</array>
But in eclipse-link am not able to find any such element (am using eclipselink-orm.xml) through which i can achieve this!
Does Eclipselink support such array to table(multi-column) mapping?
I read about #Converter through which we can convert the data type while storing to/retrieving from DB. But it looks like converter deals with single column and cannot store to two columns simultaneously.
Is there a way that i can do this through converter or any such work around? (I prefer not to use collections)
Any quick help is greatly appreciated!
Thanks in Advance!
-Alekhya
I have a class with a field:
protected DateTime insertDate;
This is mapping for this fiels:
<property name="InsertDate" access="field.camelcase" update="false" />
This field is set when with ctor
public DocuBase(DateTime insertDate)
and is persisted only when row is added to the database. I don't need property for it at all, no setter & no getter. I worked in NHibernate 3.
And now, I've moved from NHiberbate 3 to NHibernate 3.3.1, and I get this exception when session factory is created:
Could not find the property 'InsertDate', associated to the field
'insertDate', in class 'XXXX'
Why is is happening & how can I change mapping in order to get rid of the exception?
EDIT: Below answer is completly correct. But for those of you that don't need/don't want to have a property, and only field, there's another solution:
set name attribute to field name (in my case it is insertDate) and remember to have correct column name
<property name="insertDate" column="InsertDate" access="field.camelcase" update="false" />
It is case sensitivity, this will work.
<property name="insertDate" column="InsertDate" update="false" />
Looks like in release 3.1.0, there was a breaking change
NH today accepts code below. It would be better if this would throw - it causes problem when configurate NH (or 3rd party tools) other ways than by hbm, using the property name (or memberinfo) of the public interface.
[hbm]
<property name="Name" access="field.camelcase" />
[code]
string name;
public virtual string SomeThingCompletelyDifferent{
get {return name;}
set{name=value;}
}
Note: This will be a breaking change.
ps - updated answer to remove reference to use Property with private set as this was not what was being looked for and above breaking change is more relevant.
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.
I am new to NHibernate.
I am using following property elements in my hbm file...
<property name="CountryId" length="4" />
<property name="CountryForCustomer"
formula="(SELECT *
FROM SystemCountry
WHERE SystemCountry.CountryId = CountryId)" />
Here I am trying to get Country details from the CountryId that I am having in an other table.
Property "CountryForCustomer" is of custom type "SystemCountry".
But this query in formula is not working.. So someone please help me solving this issue.
Thanks in Advance....
Should it not be
SELECT SystemCountry.Country FROM SystemCountry WHERE...
as the * would return multiple columns from the query
edit If you want to return the whole object back then the property element is not your friend here. What you want to do is look at the many-to-one element, note that this is just one way to do this.
<many-to-one name="CmsTemplate" column="TemplateId" ..
e.g. here or here
the Formula mapping does not map its value from the database ,it maps its value from the dataset which is loaded in the session
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>