I'm looking for software that can do the mapping for me in nhibernate.
I looked over for this but the only thing that I found was tools for fluent. I couldn't find anythings for clean nhibernate.
Is their such a tool?
Nhiberante 3.2 has build in mapping by convention ability.
Another way is to use conform library.
You may also want to take a look at the NHibernate Mapping Generator
Just to complement the other answers, there are tools such as Visual Nhibernate that inspect your database and generate your mappings while providing hooks for you to customize the code generation process.
Related
Can anyone give/point me to 'official references' about component inheritance support in Nhibernate 3.10 ?
Already google it, but never find any reference about that.
Thanks
NHibernate (and Hibernate for that matter) does not support component inheritance out of the box. You have two relatively unpleasant options:
Map hierarchy as entities.
Write custom hydration/dehydration code using IUserType. This workaround is described in this article
(java, but should work for C#).
In the mean time you can vote for this feature to be implemented in Hibernate and maybe some day ported to NHibernate. NHibernate version of this feature request.
Here there's some doc but I'm not sure if this can help you:
https://ayende.com/blog/3941/nhibernate-mapping-inheritance
Updated
I think it's not possible! look here:
https://stackoverflow.com/q/3739806/735864
We have a large array of projects that were built using LinqToSQL and are interested in restandardizing on NHibernate. Most of the ORM we do is pretty straightforward. It occurs to me that there might be a semi-automated way to convert these systems to use NHibernate, perhaps by creating a tool that can point to a DBML and generate corresponding POCO entities and fluent NHibernate mappings.
Has anyone given thought to this or encountered any tools that could speed us along?
Thanks!
You can find a T4 impl at this link, but imho you could try to use the automappings.
Consider our DMS Software Reengineering Toolkit.
DMS can parse many languages including C# 4.0 and LINQ, producing ASTs. It can carry out source-pattern matches and source-to-source transformations on code, generating revised ASTs, and then can regenerate valid source code. It can likely accomplish your task.
I know annotations to do the hibernate mapping in Java and am looking now for a similar way to do the same in C# and NHibernate. I found out that there exists several approaches
do the mapping in xml files
NHibernate.Mapping.Attributes (NHMA)
Fluent
are there any more??
I tried NHMA and found out it had some blocking points for me...
I don't want you to discuss, whats the best way to map models to NHibernate, but I was looking for a good comparison on the internet.
Do you know such sites? What facts are the main points to consider, if I choose one of the "frameworks" listed above? I'm thinking of aspects like 'is this project offically supported by the NH-Developers?', 'are there models that can be mapped in xml-mapping but not in fluent/NHMA/etc...?'
What can you recommend?
Why?
Fluent NHibnernate auto mapping or code generation (CodeSmith, MyGeneration, T4, etc.) are the most productive ways to create the mapping files. I dislike the attributes approach because I like to keep my POCOs plain.
Another option, if you don't mind attributes, is Castle ActiveRecord.
Here's an article that might help you decide.
Can anyone throw some light on tools that can be used with NHibernate and which perform the below mentioned tasks:
Generates the Mapping File
Generates the Entity Class
Generates the Configuration file
And also provide information whether these tools are open source or licensed.
Thanks
One tool I've used that did a decent job was CodeSmith. It looked at the existing database and created the entities, mappings and configuration file. However, this is only to be used as a starting point as there are many tweaks you'll likely want to do to make it more usable and better performing. Things such as when to lazy load vs. eager load, creating subclasses or components. This tool really just mimics the database structure in your entities which is not always the best way to represent in code.
This is a licensed solution but it includes a fully functional demo you can use to gen your files initially. After that, you'll most likely just enhance just as you would your database.
Another is MyGeneration. Same thing, it'll get you 75% of the way there in most cases.
Just be cautious as to which version of NHibernate these tools are producing. They may be using an older version which may have some obsolete code.
I really like Visual NHibernate (http://www.slyce.com/VisualNHibernate/).
Not free, but has a nice set of features, including the definition of templates for the entities, and generating both HBM.XML as well as Fluent NHibernate mappings.
A similar question with some answers you might find useful is already on SO.
NHibernate Generators
As mentioned in that question's answers, fluent NHibernate is a good option. It just went RTM. You can find more info at http://fluentnhibernate.org/
Check out LLBLGen Pro. It's got a competing ORM but can also act as a code generator for nhibernate. Very good for DB first work.
I just want to do a quick poll to see if Fluent Nhibernate is well received or if it is having lot of issues. I like Nhibernate but I definitely see the problem with xml to do mapping.
So, I am looking forward to community members for some insight and help me pick one over the other.
I am not considering either linq2sql or entity framework at this time.
I like Fluent NHibernate and I think it's mature enough if you are going to start a new project. Using it on a new project should allow the Fluent NHibernate project to continue to mature as yours progresses. There is a possibility for breaking changes (as happened recently with the convention mappings) but you should be able to deal with those. I've had a few issues with the mappings but the project is pretty responsive to bug reports and has mostly worked as expected.
The mapping options are:
Xml mappings - Standard of NHibernate. The maintenance headaches are well known but the advantage is that you have access to all of the configuration options provided by NHibernate. There are a few less-used configuration options are still being added to Fluent (at least last time I paid attention). So, if you are anticipating some crazy mappings, you may want to consider this option.
Standard Mapping - Provided by Fluent. You can create the mappings through code and is much better for refactoring and authoring. Not much to say about it, in my experience, other then that it works well and is a big improvement on the xml option.
Auto Mapping - Provided by Fluent. Allows you to map object properties by convention and it attempts to create the mappings automatically. It's a good idea but I think it still has some maturing to do. I'm currently using this mapping method and it works fine but I have ended up writing a large number of conventions and specifying the object relationships that it doesn't feel like it's saved much effort from the standard mappings.
Fluent NHibernate also provides nice test helpers for testing your mappings and some configuration APIs that can make it easier to configure NHibernate. Overall, it's a good project and it provides some nice additional functionality to NHibernate.
edit:
One additional thing to note: If you start off with Fluent NHibernate and decide it isn't going to work for your scenario, you can easily migrate back to the xml mappings. Fluent NHibernate allows you to export the mappings it creates and you can use those exports to not lose whatever mapping work you've already done.
One of the best advantages of using Fluent Nhibernate over vanilla NH is nice integration testing with PersistenceSpecification<T>:
[Test]
public void TestProductSave()
{
new PersistenceSpecification<Product>()
.CheckProperty(x => x.ProductName, "Wax")
.CheckProperty(x => x.Price, 20)
.VerifyTheMappings();
}
I've been using fluent on a new project of mine. The only minor bump I've hit so far is that it doesn't play so well with Castle Windsor out of the box, but it was quite easy to extend Windsor to do the job. Other than that I've been loving it. It's much more concise than the XML mappings.
The nice thing about fluent is that it isn't an all or nothing investment. You can write most of your mappings in fluent and if you find any issues you can map those classes in the standard XML mapping until the fluent issues are resolved.
Like any good answer, it depends.
I didn't get as much mileage out of the automapping features as I would have wanted to. I often have to work with preexisting databases.
I already had several projects using NHibernate under my belt, so using the hbm mapping wasn't difficult. After I figured out how to include in the hbm schema, it was much easier.
The one real advantage I gained from having fluent-nhibernate is being able to refactor my domain classes and have my mappings automatically change. I didn't really notice that much of a speed increase in writing the mappings.
Like anything, YMMV.
I am using FNH for a new project. What I like the best is the ability to generate and build the database directly from the entity classes.
I have had to write a few conventions for the properties but I'd rather that then maintain more than one list for each class.