We're investigating using RIA Services (July 09 Preview) to expose parts of an existing EF model. We've added a Domain Service class to our web application and specified the EF model to use and selected a few of the entities we wish to make available via the domain service (some have editing enabled, most do not).
We build and everything is great, but if we want to add an additional entity to the domain service how do we do that. Is it a case of delete your current class and re-add and this hole will be plugged when RIA Services hits RTM?
I agree, that's annoying to type in all that manually every time the DB changes. What i end up doing is creating a new temporary domain service classes (and metadata) and cut&pasting the code into the existing domain service and then removing the temp service from the project.
Another option can be (didn't try it) to make the generated file a partial class, put all the new queries into a separate file and every time the DB Schema changes just blow away the generated file and recreate it using the wizard. Just a thought
You can just add the code for the new entities... just add the right methods, query, and depending on which operations you need, insert, update, delete and custom ones.
Yoiu shouldn't have to delete your current class, which theoretically contains a bunch of interesting app logic (I'd imagine) just because you want to add an entity.
My solution to this problem was to create a code snippet that does most of the work.
I only have to type efdsmethods, tab twice, and replace the EntitySet name, EntityType name, and entity variable for the methods to use and then I'm done. It makes adding the 4 standard methods very easy.
I've submitted my snippet as a patch (#10154) to the Silverlight Contrib project on codeplex, but it hasn't been accepted yet. Until then you can download the snippet from here.
Hope this helps you.
Related
Let's say that I have a simple WPF or Winforms solution. To that solution I add a new project (based on a class library template , which I then reference in the main project) which is intended to be a data layer containing an entity framework data model. When I create the data model in the new project the connection string that it uses gets added to the app.config file of the main project in the solution.
Now let us say that I want to add two more projects to the solution (both of which will again be based on class libraries) to contain details of WCF services that I wish to use. In each case I add the WCF service by using the ADD Service Reference option from the right click context menu of the projects.
Unlike the data model project though the bindings for the service model get added to the local projects app.config file ass opposed to the app.config file of the main start-up project.
Should I simply copy those bindings to the start-up project's app.config file, or should I copy and then delete, or in fact should I be doing something completely different. Thus far trying combination of the first two suggestions I get error messages connected with endpoint configuration, however my knowledge of WCF is not really sufficiently good to fully understand the MSDN articles that the error list points me to.
Note that if the service references are added to the main project I get no errors whatsoever, so I figure this must be a configuration problem of some description.
Would anyone be able to provide the correct procedure for adding projects that essentially contain no more than a WCF service reference to an existing visual studio solution.
Edit
The screenshot below shows my main app.cofig file after having copied over the bindings configurations from the two service contracts. I'm not sure whether I should have commented out the bit that I did or not, I had thought that by doing so I might get rid of the blue squiggly underlines telling me the following (which I must admit to not understanding):
Warning The 'contract' attribute is invalid - The value 'ErsLiveService.IERSAPIService' is invalid according to its datatype 'clientContractType' - The Enumeration constraint failed.
You're likely getting the blue squigglies because the namespace ErsTestService is defined within the project in which you created the service reference. If the root namespace of that project is MyServiceReferenceProject then try changing the namespace to MyServiceReferenceProject.ErsTestService.IERSAPIService.
I have Umbraco 7 website with MVC.
I want to perform some custom action on the database.
As I understand I should be using DbContext to connect.
I have referenced System.Data.Entity to get to DbContext class. However when I'm trying to use DbContext I'm getting an error saying
The type or namespace name 'DbContext' could not be found (are you missing
a using directive or an assembly reference?)
In my models namespace:
public class umbracoDbDSN : DbContext
{
//some code
}
Can you let me know what I am missing?
Thanks
You are mixing things up. Umbraco uses PetaPoco as ORM, not entity framework. You don't need to include the System.Data.Entity. Neither you need the DbContext.
However, if you have existing DataLayer logic which you need to incorporate, for legacy systems, you might need to continue with your code above. Then look for entity framework tutorials on the internet to continue your journey.
If you are not dragging legacy stuff, then the question is: do you want to perform queries on custom tables or do you want to query the Umbraco tables for some reason.
Let's start with the last one. Querying the umbraco tables:
If you want to connect to the umbraco SQL tables, I start wondering why. There is a ContentCache, which is blasting fast, and it enables you to query very quickly everything you need from the content section. You have API's for relationships, media, users, members and everything you need. So the question remains, WHY would you ever connect to the umbraco tables.
However, if you want to store data in custom tables, I would read this article of Warren: http://creativewebspecialist.co.uk/2013/07/16/umbraco-petapoco-to-store-blog-comments/
The idea is simple, you reuse the existing code base to extend umbraco behaviour without storing stuff in the content section.
Below a simple example for reusing the databaseconnection while querying some proper created table...
var db = ApplicationContext.Current.DatabaseContext.Database;
// Fetch a collection of contacts from the db.
var listOfContacs = db.Fetch<Contact>(new Sql().Select("*").From("myContactsTable"));
Some days I love my dba's, and then there is today...
In a Grails app, we use the database-migration plugin (based on Liquibase) to handle migrations etc.
All works lovely.
I have been informed that there is a set of db administrative meta data that we must support on every table. This information has zero use to the app.
Now, I can easily update my models to accommodate this. But that answer is ugly.
The problem is now at each migration, Liquibase/database-migration plugin, complains about the schema and the model being out of sync.
Is there anyway to tell Liquibase (or GORM) that columns x,y,z are to be ignored?
What I am trying to avoid is changesets like this:
changeSet(author: "cwright (generated)", id: "1333733941347-5") {
dropColumn(columnName: "BUILD_MONTH", tableName: "ASSIGNMENT") }
Which tries to bring the schema back in line with the model. Being able to annotate those columns as not applying to the model would be a good thing.
Sadly, you're probably better off defining your own mapping block and taking control of the Data Mapper (what Hibernate essentially is) yourself at this point. If you need to take control of the way the database-integration plugin handles migrations, you might wanna look at the source or raise an issue on the JIRA. Naively, mapping your columns explicitly in the domain model should allow you to bypass unnecessary columns from the DB.
I have a class running in a winforms app which uses EF Code First. The DbContext is created via DI through the class constructor. All works well.
The problem is the data being referenced is also being modified via a web site, using the same DI pattern with EF Code First, and the data changes are not being reflected in the context instance in the winforms app.
I can solve this by recreating the DbContext object in winforms every time I access it, but seems to be more of a service location pattern to me?
Is there a true DI technique to achieve this?
Or should I remove the context from the DI and use service location?
Were you not happy with the answer to your other question (http://stackoverflow.com/questions/7657643/how-to-force-ef-code-first-to-query-the-database) which suggested using Detach, AsNoTracking or Overwrite Changes?
1) Maybe you could pass an interface that has the ability to create a DbContext, instead of the context itself.
using(var context = _contextFactory.Create()) {
var entity = from table in context.Blah...;
}
The Create method could either create the concrete class itself (defeating the DI pattern a bit), or use service location to have one created for it. Not that nice, but it's better than embedding service location calls everywhere and still means you're controlling the lifecycle yourself.
2) Change the WinForm to read from a webservice run by the website, effectively similar to disabling caching.
3) Deep in the heart of MVC (well not really that deep) it is referencing the DI container directly and using it as a service locator to pass as arguments for newly created objects. Technically you could do something similar in WinForms, but it would need you to split your application up into little chunks (controllers) that don't have a very long lifetime. Maybe it's worth looking at some MVC/MVP frameworks for WinForms, although I found myself cringing at most I saw after a quick google.
The problem is the data being referenced is also being modified via a web site, using the same DI pattern with EF Code First, and the data changes are not being reflected in the context instance in the winforms app.
This is a problem with your expectations.
If your web service and window forms app are in separate processes, they won't share in-memory data.
If you want to sync their in-memory data, simply re-query in one context after committing to the database in the other. This is the same as trying to share data between different SQL connections.
I can solve this by recreating the DbContext object in winforms every time I access it, but seems to be more of a service location pattern to me?
If you want to recreate the DbContext repeatedly, you could use an abstract factory to allow manual re-creation of the object, yet allow you to inject the specific implementation into the factory.
This is not (necessarily) the Service Locator pattern, and you would have to ensure that you manually dispose your DbContext instances. I'd give you some example code, but different DI containers have totally different ways of accomplishing a factory pattern.
Or you could simply make sure that you commit your data on the web service side, and re-query the data on the WinForms app side.
How to generate new table related code in existing Ria Service without deleting it. Please Suggest best Practice.
I am having one domain service. I have modified lot of auto generated code and meta data. Now I want to include couple of more tables auto generated code without deleting it.
Your best option is probably to add a second, temporary doamian service that includes those tables and then copy the code over to the existing domain service. Remove the temporary domain service once you are finished.
The other option is to hand craft the new code. Use the existing code for the other tables as an example.
My understanding is that the generator is only intended to be used for the creation of new domain services.