I'm looking for a NHibernate Mapping generator which could generate a mapping file (hbm) and SQL Script from a C# class. I've found generators for the other way around, but not for this case.
Can you guys point me to nice generator?
Thanks a lot!
With Fluent NHiberate you can do without mapping files. In the instances where the automapping doesn't work, you can override.
This post discusses schema generation
Fluent Nhibernate Schema Generation
The newest, fastest and most extensible way to configure NHibernate is ConfORM.
You don't need to generate xml files (although you can do so if you want). It's an order of magnitude faster than Fluent NHibernate and, overall, less work.
For some examples, read Fabio Maulo's posts.
Related
How to write Queries for retreving, Checking Existence, and all we do in SQL
using NHIBERNATE (FLUENTNHIBERNATE)
Is FluentNhibernate is used in these Queries.
And
Which one is better Fluent Nhibernate Mapping or XML Mapping
Is there any relation or should i know LINQ for learning Nhibernate?
i can see several questions:
"How to write Queries for retreving, Checking Existence": see here for the different querylanguages in NH http://fabiomaulo.blogspot.com/2009/09/nhibernate-queries.html
"Is FluentNhibernate is used in these Queries": no FNH is used to configure NHibernate: alternative for hbm.xml and hibernate.cfg
"Which one is better Fluent Nhibernate Mapping or XML Mapping": in most cases FluentNHibernate is much easier to write than xml and covers 95% of options possible in xml. For beginners i would recommend FluentMappings because a lot of sensible defaults make it easier to get something to work.
"Is there any relation or should i know LINQ for learning Nhibernate?": LINQ is one of 6 ways to query in NHibernate. It is an elegant way but neither required nor the "works in all circumstances".
I have several projects using NH and FNH to generate the mappings (some Fluent some Automapped). There are still some bugs and missing features i need, but it seems that FNH could die because of mapping-by-code integrated into NHibernate.
Question: Contribute to FNH or to migrate the mappings to mapping-by-code or confORM and fixing problems/implementing features there?
At our office, we have been using NHibernate for 3 years now. We've been thinking about making a move to Fluent Nhibernate but never made the move. Using hbm.xml files was still the easiest to debug/alter. Two common problems of those xml files are that they are all validated during the creating of the sessionfactory and they are not refactor-safe.
Due to a bug I had to update a newer release of NHibernate (we were using NHib 2.1.2GA) and when I implemented 3.2GA we also were handed the ability to use loquacious mappings (mapping by code). I decided to use Loquacious over Fluent because I don't have a dependency to another project (Fluent) and the fact that NHibernate won't be shipped if mapping by code is broken.
Be aware though, that Loquacious mapping isn't complete either. While I was mapping everything by code, I found out basic stuff like property-ref wasn't always implemented. Thus even though it's shipped, it's not 100% complete. And while this will not come as a shocker, it has bugs. yes. really. ;-)
for more info on (reported) bugs, check out the NHibernate bug database: https://nhibernate.jira.com/browse/NH
Hope this helps.
Regards, Ted
thx to #TedOnTheNet i will continue to use and contribute to FNH, because it will take a while until mapping-by-code reaches FNH in some areas
Automapping
Fluent API tells a lot better which possibilities there are
far more verbose mappings
.Database(SQLiteConfiguration.Standard.InMemory()) is still easier to figure out than
.DataBaseIntegration(db =>
{
db.ConnectionString = ???;
db.Dialect<SQLiteDialect>();
db.Driver<???>();
});
and some features:
CompositeId and Table per Subclass
default values for legacy columns
property refs
Update: some features from hbm.xml (and FluentMapping) will not be possible at all with mapping by code:
default values for legacy columns: database column to constant value without the need for a property in the entity class with mapping by code
query only properties/collections: http://ayende.com/blog/4054/nhibernate-query-only-properties
NH 3.2 does not have anything remotely equivalent to FNH's Automapping, as far as I can tell. (For me, that would be a dealbreaker).
Edit
The FNH Automapper can deal with most of the common patterns in an object model, such as inheritance, one-to-many relationships, self-referencing, etc - without requiring any help from the programmer. So far, pure NH has not achieved this level of automation.
Also, James Gregory has publicly stated that he will continue to develop FNH, at least in the near term. (Think I saw this on the FNH Google group a few months back, but I'm not sure exactly where).
I am trying to integrate NHibernate into an existing application with several hundred tables. Due to the fact that there apparently wasn't a strict adherence to conventions, I am unable to use Automap. As a result, I'm going to use Fluent to manually map over all of the associations.
Rather than doing it by hand, I'm hoping that there is a tool in existance that can either run through my solution or the database and stub out mappings.
Does anyone know of any project out there with this in mind?
Thanks!
I don't know of a tool that does it in Fluent, but there are plenty of options for doing it with the old hbm xml files. CodeSmith and MyGeneration are two that are recommended as a starting point for your classes and hbms.
LLBLGen Pro V3 will do exactly this, it can generate either tradition .hbm.xml or fluent mappings for your entire database.
Old question, maybe still relevant to some. If you are looking for an open source solution, try NHibernate Mapping Generator
Is it possible to create the database from the classes with entity framework 4.0? I found many tutorials on how to do it the other way round. But since we have already implemented and tested all classes of the domain we'd like to avoid changing them to much.
If I used the wrong keywords in Google I'd appreciate you could post a link.
Cheers,
CA
Yes, it is possible. The approach is known as "model-first".
You define your entities with designer then call for "Generate database script" or something. Run this SQL against a database and it will create tables and relationships.
This is quite easy to do with Fluent NHibernate using Auto Mapping. You could also use Fluent Mapping if you want more control over how your entities are mapped, but this will require writing mapping classes. It shouldn't affect your existing classes though.
While looking up an other question on Stackoverflow I found an the solution for my problem:
Entity Framework 4 / POCO - Where to start?
I know that you can generate a database from classes and their mappings using nHibernate, but I can't find any good links to do this the other way around. We have a database that has already been designed, and we are looking at using nHibernate. It would be nice to use a tool to generate the mappings and classes from the database, and then we could tweak/manipulate them to suit our tastes.
NHibernate Mapping Generator
You can use nhibernate with an existing database. It is a matter of writing the mapping files.
I also recommend using Fluent Nhibernate...I started using this after this community recommended it..
Look at subsonic as well if you do not like maintenance of mappings.