Hi i write because i have configured the Audit for one single table for all my entities and its working fine for the general tables in my model, but with the Many-To-Many tables i don't know how can i do for setup the "AssociationEntryRecord"? the event is fired by EF when i do one change in this tables but i don't know how saved!
Could you please help me with this questions, thanks in advance for your help & the library...
For configuring the Entity Framework event provider use the fluent API provided by Audit.EntityFramework.Configuration.Setup()
You can include the associations as follows:
Audit.EntityFramework.Configuration.Setup()
.ForAnyContext(config => config
.IncludeIndependantAssociations());
And about your sample code (what you should have included as textual code and not as an image):
The first line is not needed, since the UseEntityFramework() will
override the DataProvider
The primary key value can be calculated as: entity.TablePk = entry.PrimaryKey.FirstOrDefault().Value.ToString();
Related
Mates, I want to update a role description using my application
I don´t know what is the better way to connect to the database and run a UPDATE statement.
Would it be Entity Framework? LINQ? None of this 2 options..
Please, suggestions.
I would say that Entity Framework would be currently the best solution for you. Not only it is strongly supported by Microsoft (well Silverlight was as well) but:
If you start with it, you can use designer. It's graphical UI will guide you when generating the model (based on database) or generating the database schema when starting with model.
Read some tutorials abut it:
http://msdn.microsoft.com/en-us/data/ee712907
And later take a look how to use some more profesionla techniques as Repository pattern or unit of work
http://www.asp.net/mvc/tutorials/getting-started-with-ef-using-mvc/implementing-the-repository-and-unit-of-work-patterns-in-an-asp-net-mvc-application
Not Linq ..well yes linq, but linq is the querying framework where as entity framework is the object relational mapper. So Both actually. You could do this in various other ways but those two technologies work very well together from my experience.
In Visual studio you would create a new ADO.NET project template which you then hook up to your database. and then you can update the tables and do a whole bunch of stuff. Linq is build into .NET so technically you can query any objects using linq ( which makes it so much fun ) and because your entity is an object you just reference it ( first declare it ) and then play with it
FooModel foo = new FooModel(); // Entity
var fooQuery = from _ in foo.DescriptionTable // Linq query
where _.Description == SelectedDesc // table selection query
select _;
foo.Add(fooQuery); // add to database
foo.SaveChanges(); // save changes
Something like that. There is a bit more to it that would project specific but you would have to give more details.
It is most certainly worth learning both technologies and have doubt you will find them very useful. Both can get very complex but for what you need it for you just need the basics down and then you can explore from there.
I am using EF 4.3 in an ASP.NET WebForms application. I've started with model first approach with context object of type ObjectContext and POCO code generator (via T4).
At the beginning the Context was created at the beginning of every service method. While working on performance I decided to switch to context per web request. Unfortunately I have encountered an issue with Table-per-Type inheritance. I have two entities: Offer and OfferEdit. They are in a one to one relationship, and both share the same primary key. Basically an OfferEdit (OfferEdits table) is created once an Offer is being edited.
I query the context for a particular Offer entity more then once during web request. The error I get trying to execute:
var offer = Context.Offer.Where(o => o.Id == offerId).FirstOrDefault()
when this offer is already loaded to Context.Offer.EntitySet is
All objects in the EntitySet 'RuchEntities.Offer' must have unique primary keys.
However, an instance of type 'Ruch.Data.Model.OfferEdit' and an instance of type'Ruch.Data.Model.Offer' both have the same primary key
value,'EntitySet=Offer;Id=4139'.
Will appreciate all advice.
Sounds like you are misusing TPT inheritance. To make it clear EF inheritance works exactly same way as in .NET - the entity can be either of type Offer or OfferEdit. You can convert OfferEdit to Offer but it is still OfferEdit. It can never be of both types which means you can never have Offer entity with Id same as OfferEdit entity because same key cannot be used by two entity instances. You also never can change instance of Offer to OfferEdit because .NET doesn't allow you changing type of existing instance.
Could someone with some good knowledge answer this question please. Im having a problem with the schema in my Students.aspx page. I have done the walkthrough, but I get an error and I have copied the edmx file from the sample into my application and I still get the error. This is the error:
'EnrollmentDate' is not a member of
type 'SchoolModel.Person' in the
currently loaded schemas. Near simple
identifier, line 6, column 4.
I have also created a new EntityDataSource and I have the same problem. The sample works fine but I can't seem to get the EnrollmentDate and HireDate fields to be part of the 'SchoolModel.Person' Entity. The part which is Upto setting the EntityTypeFilter then I run the app and I get problems
It sounds like you're following the example on MSDN. By the end of the example, the fields EnrollmentDate and HireDate are no longer on the SchoolModel.Person class, they're on the subclasses SchoolModel.Instructor and SchoolModel.Student.
I faced the same problem while going through that walkthrough. The solution: Just delete the old EntityDataSource control on the page, put new EntityDataSource, configure it as given in walkthrough (with entity set name: People; EntityTypeFilter: Student or instructor), And every thing works as it should!!
Faraz
It sounds like you may have missed one or more EDS controls when you added the EntityTypeFilter attributes. Are you sure all your EDS controls that access students or instructors have EntityTypeFilter="Student" or EntityTypeFilter="Instructor"?
In my project many tables are linked to aspnet_Application table by ApplicationId foreign key. I don't want the users to view or edit it, so I'm looking for way to preset this sql table field value before the insert query is executed. I still have scaffolding enabled for this column (in order for DD to generate the right sql script) but I'm hiding this column/field in all my edit/list/insert pages.
Ideally I'm looking for a place to inject my code right before DynamicInsert is executed for any table in my LinqToSql class.
Thanks
So after some digging around I came up with an acceptable solution. I've created a partial class for my data context and added a partial Insert_ method for every table that's linked to the aspnet_Applications. In every method I set the ApplicationId field to current application id.
It looks like this:
public partial class MyDataContext
{
partial void InsertMyTable(MyTable instance)
{
instance.ApplicationId = HttpContext.Current.Session["ApplicationId"] as Guid?;
this.ExecuteDynamicInsert(instance);
}
}
Note that you can't execute other LINQ statements while in this method. In particular I had to store the application id in session rather than querying the aspnet_Applications table.
While this is acceptable solution it isn't perfect (a lot of repetitive code) so if anyone knows better throw me a bone here :)
In the future the best solution would be to use DomainService part of .Net RIA Services preview just released at MIX09 see there videos here:
.NET RIA Services - Building Data-Driven Applications with Microsoft Silverlight and Microsoft ASP.NET
Microsoft ASP.NET 4.0 Data Access: Patterns for Success with Web Forms
The first is an introl to .net RIA Services from the point of view od Silverlight but more of it applied to DD the second is David Ebbo's presentation at MIX and shows how DomainService works with DD I think this is the way forward as you can do all your business logic here in the DomainService.
I have a problem with the following Linq query using Entity Framework:
from o in ctx.Entity
where o.EntityID = entityid
select o;
Simple enough right? Well the 'Entity' set is the parent class of a whole lot of other classes. The generated SQL for this simple query is about 20K worth of characters with a slew of 'case' and 'union'. In addition of taking a while for the framework to compile the query, it takes a while to execute too.
So how can I improve the SQL generated by the framework in case of queries using classes with heritage? Or what other technique can I use to avoid this problem?
AD
The reason it is doing that is because of the relationships of Entity with other tables in your database. To cut down on that, you need to read up on how to better control the explicit/lazy loading of references that EF is doing for you
http://blogs.msdn.com/jkowalski/archive/2008/05/12/transparent-lazy-loading-for-entity-framework-part-1.aspx
No post like this would be complete without a plug for nhibernate, which is more powerful/robust/performant/and easier to use ;-) but hopefully that link will help you out