I'm using the entity framework that comes with 3.5sp1, and I'm trying to add a custom entity that I will propulate with searchresults from a stored procedure. But I have problems with the designer....... when I pick "Add + Entity" and give it a name, and hit save, the whole diagram stops working...... blah entities namespace could not be found..... all the other entities have lost its reference or summet. Works when I add a "table" to it that exists in database. But when custom it screws everything up.
How should I fix this? I've imported the function, I just need to add an entity for it...
I've read http://blogs.microsoft.co.il/blogs/gilf/archive/2009/03/13/mapping-stored-procedure-results-to-a-custom-entity-in-entity-framework.aspx but I cant get to step 3 since of all the errors when saving on step 2.
/M
Apparently I must have the primary key option checked when adding entity.
Related
Everything I find through Google refers to Code First so I'm wondering what the Key attribute is actually doing in regards to a Database First design? I'm mainly curious because a lot of the entities contain composite keys so I've been adding the Key annotation to the respective properties, but is this really necessary? And if so, what do I gain from it?
If you're using the database-first workflow (i.e. you have an .edmx file in your solution). Then the Key attribute will have no effect.
However, if you're using the code-first workflow to map to an existing database, the Key attribute tells code first that that property is part of the entity's primary key.
For more info on the different workflows see this video: Visual Studio Toolbox: Entity Framework Part 1
It appears to me that a strange phenomenon is occurring with inherited entities (TPT) in EF4.
I have three entities.
1. Asset
2. Property
3. Activity
Property is a derived-type of Asset.
Property has many activities (many-to-many)
When modeling this in my EDMX, everything seems fine until I try to insert a new Property into the database. If the property does not contain any Activity, it works, but all hell breaks loose when I add some new activities to the new Property.
As it turns out after 2 days of crawling the web and fiddling around, I noticed that in the EF store (SSDL) some of the constraints between entities were not picked up during the update process.
Property_Activity table which links properties and activities show only
one constraint
FK_Property_Activity_Activity but
FK_Property_Activity_Property was
missing.
I knew this is an Entity Framework anomoly because when I switched the relationship in the database to:
Asset <--> Asset_Activity <--> Activity
After an update, all foreign key constraints are picked up and the save is successful, with or without activities in the new property.
Is this intended or a bug in EF?
How do I get around this problem?
Should I abandon inheritance altogether?
Not a but but a poor visual designer.
Its generally best to simply manage the Entity XML by hand.
No inheritance works well for many situations.
Basically I use the update from database in the visual designer but knowing that the designer has its quirks. I have simply used the update from database to stub out the basics of what I want. Then I go into the Entity XML my self and clean it up the way I want. Just of note Complex types are a pain with the designer. If you plan to use complex types get ready to learn your Entity XML well.
I'm working on a C#.NET 3.5 WCF RIA Services app and having an issue with my Entity Framework model.
My entity Foo is mapped to a DB table and has a primary key called FooId. My Bar is mapped to a DB view. I've selectively designed this view to generate a composite key in the EF using two of the columns (by making sure they were non-nullable and the others are all nullable. This was done using NULLIF and ISNULL in the view design.)
I'm able to add this view to the model with no problem but I keep running into an issue when I try to map an association between the two. Foo should contain many Bars but I keep getting the following error when I add the association:
Unable to retrieve AssociationType for
association 'FK_Bar_Foo'
According to this page, it looks like this might work if I can properly name the association (since RIA Services looks for specific names.) I've tried several variants of names that match the pattern of other associations with no success. Does anyone know if there's a place I can look to find out what name it's looking for?
Thanks,
After some research I found a workaround to the issue here. The problem with this solution is that you have to repeat it every time the model is updated, which just won't work for me. It appears the current version of the EF doesn't support this type of relation.
The solution I finally went with was to redesign the client to independently call the service and request an entity collection by passing the primary key (FooId) of my Foo type. It's not the best approach (and requires a lot more manual coding) but it does the job. I hope Entity Framework version 4 solves this limitation.
Maybe im just an idiot, but I am having serious issues mapping relationships with the new entity framework.
When using LinqToSql, you would just right click the table, add association, select the two tables, and selected the property from each table the association was based on. End of story, it worked perfectly.
Using the entity framework and the slightly different visual editor, I go about doing the same thing, but there is no option in the initial association menu to select the actual properties. So after that, you bring up the association map, and thats where the problems start... What the hell? The only thing you can edit in here is the column to which a key is mapped, but the only columns you can choose are those in the same table as the key... Im completely lost.
Instead of mapping the association in the designer, try setting up your foreign key constraints on your tables then update the model from the database and the associations will be setup for you.
There is no possibility to map association end to an incomplete Entity Key.
This is an Entity Framework limitation.
I am getting an error 3007 when I add my entity model to my solution.
I found these links:
Good explination
Short answer
About this error:
Error 1 Error 3007: Problem in Mapping
Fragments starting at lines 89, 94:
Non-Primary-Key column(s) [Person_ID]
are being mapped in both fragments to
different conceptual side properties -
data inconsistency is possible because
the corresponding conceptual side
properties can be independently
modified.
Their Answer: I agree with their conclusion that by simply deleting the Scalar Property Person_ID and leave the Navigation Property my problem is fixed. However this is not very scalable since I am dynamically building my database and my entity is updated very often. I dont want to have to go through and clean up my entity every time I update it.
My Question: Is there a way to fix the error by correcting the way EF builds the entity? Or is there a way to remove the Scalar Property through code? Perhaps there is even a few options that I am overlooking.
Try to remove foreign property column from Entity set using entity model design it will solve your problem
For example
We have two tables one is customer and other one is order, using entity model design we added association between customers and orders when we do this Ado.net entity framework i will add navigation properties to both below tables.
Like
Customer.Orders - Here order is list
Order.Customer
One - Many relation.
So we need to remove property from with name CustomerId[Foreign key column] from Order entity set.
For reference:
http://social.msdn.microsoft.com/forums/en-US/adodotnetentityframework/thread/2823634f-9dd1-4547-93b5-17bb8a882ac2/
My experience with EF v1 is similar to yours. When the EDM is generated incorrectly and you can't work around the issue, you have to manually edit the EDM. EF v.Next (Entity Framework v4 I believe) will support "Code Only" Entity Data Models, and the EDM designer is supposed to be much better. One or the other improvement should make our lives easier. Until then...