Am very new to Entity Framework. I am using vs 2012 professional 2012 for building my mvc4 app.
I will try to explain problem in my limited knowledge
I have created Ado.net entity data model. After that I have chnaged db for setting relations. After "update model from database" the relations are not gettng added to model classes. So when I run my app errors like
The relationship 'x.FK_Privileges_Module' was not loaded because the type 'x.Privilege' is not available.
is shown
How can I solve this. I even tried adding manually the relation to corresponding . cs file and still getting error for every newly added relation.
How can I solve this?
You can remove entities from model designer (Press Yes when message box will ask) and then add entities again.
Note: To delete, select entities and press delete key
The edmx is not able to find a Primary Key on Privilege and therefore the foregin key is not valid.
Add a Primary Key on Privilege
Related
I am using Visual Studio 2012 and i have created a .sdf and .edmx for my database.
I was wondering what would be the best way to set the relationships between the entities.
I have tried just setting the association with the multiplicity set and get an error saying that they are not mapped.
Also how do you set the foreign keys.
I am trying to create a estate agent like system to book appointments online and in branch. I am creating it in C#.
I Assume you are going Database first.
If so, if you just simply creat your foreign keys and constraints in your database and then try to add your entities again, then your edmx file will have the relationships and everything.
I am working on a custom ado.net provider and using that provider I am integrating Entity Framework support in Visual Studio 2010. I'm creating all possible mapping and reading all the related metadata from database for table objects. For my test, a table contains primary keys and and other fields. When I create a model from database using this table and I get a model with all column mappings and everything but I also get error messages that follow:
The model was generated with warnings or errors.
Please see the Error List for more details. These issues must be fixed before running your application.
Loading metadata from the database took 00:00:11.4799371.
Generating the model took 00:00:04.2751189.
Added the connection string to the App.Config file.
Writing the .edmx file took 00:00:00.0005060.
If I open the .edmx file with XML editor, I see the following error:
<!--Errors Found During Generation:
warning 6002: The table/view 'sqlfire.APP.CUSTOMERS' does not have a primary key defined. The key has been inferred and the definition was created as a read-only table/view.
-->
It also added a DefiningQuery with a SELECT ... statement for the table.
I am going in a circle to find a solution and desperately looking for some help on this issue.
From the error message looks like one of your table/view doesn't have a Primary-Key. EF needs a Primary-Key in every table in order to generate Entity keys.
You may still be able to run your application, but I strongly suggest you add primary keys as warned.
I'm experiencing an unusual issue with Entity Framework in VS2008. The problem is when I create my Entity Model from my existing database, the designer add all the corresponding tables but it appears that it randomly omits some of my Foreign Key fields. Yet if I browse the Model in the Browser I can clearly see that the fields were included.
This became apparent when during the build I started receiving multiple errors that these fields were not mapped. This led me to manually add the fields in the designer to the corresponding tables and map them to the datasource.
After this however, I get multiple errors:
Error 102 Error 10023: Could not find the conceptual model to validate.
Error 103 Error 10024: Could not find the storage model to validate.
Error 104 Error 10025: Could not find the mapping model to validate.
Error 105 Could not find the Conceptual Schema node to embed as a resource for input file
Error 106 Could not find the Storage Schema node to embed as a resource for input file
Error 107 Could not find the Mapping node to embed as a resource for input file
When I open the edmx file in XML Editor, the file is riddled with squiggly lines.
I have successfully created the Entity Model in VS2010 without issue but our client isn't at 4.0 Framework.
I have identified others having the issue but I can't find any resources to assist on fixing the problem.
Any suggestions would be greatly appreciated.
This is probably EF1 did not support foreign keys. So for foreign key columns EF will create navigation properties but will not create foreign key properties on the Entities. You can find foreign properties in model browser but this is in the model representing the database and not the conceptual model. Note that navigation properties are modeled based on foreign keys in the store and you are not losing the relationship functionality even though you don't have foreign keys exposed. In other words - if you use navigation properties in queries they will be translated correctly to use foreign key values in the SQL queries. One thing where having foreign key properties in the conceptual model is very useful is when you would like to reason or modify a relationship without having to load the related entity - if you know the key value you just set the foreign key property to this value and you are done with it. This is impossible in EF1 - whenever you need to change the relationship or query against a related entity you first need to load said entity and use navigation property.
I am using EF 4.0 and am generating my Entity Model (.edmx) file from my database. I have several foreign key constraints for Cascade OnDelete, however, these are not getting set on my associations in my entity model. I click on the association and it shows End1 OnDelete: None.
When I check the Delete rules in my SQL Server 2008 database on my foreign key constraint, it says 'Cascade'.
Is there something I am missing to get the Cascade OnDelete flag to set in my entity model?
This answer
"I was having the same problem with SQL Server. When I tried to update mode from database, it didn't pick up the cascade rules. Note that the rules were added after the model was already created. I even tried deleting a table from the model and adding it back in. That had the same effect - no cascade rules.
However, when I created a brand new model with the same exact tables, it picked up the cascade rules. So my solution was just to delete the old model and create a new one with the same name, etc.
I guess is that there is something wrong with the update model from database process."
from this thread worked for me.
I've got a pretty large DB hooked up to my Entity Framework. I've got one particular set of tables where a common key (fk) was deleted from the design. When I "update the model from the database", I get a series of errors about this now-missing key.
Why doesn't the update process accurately detect that this key was removed? Also, if I manually remove the property from the model, I just end up with other errors. I also tried to simply delete the table and re-add it, but now the table doesn't show up in the "Add" section of the update wizard.
So, short of deleting the entire thing and starting over, is there any way to recover gracefully? Has the EF team released any newer versions of this wizard that has some of these issues fixed in it already?
Entity Framework does get confused from time to time. What you need to do is delete the Entity Table from the model, then rename the table in SQL Server to TableName_Temp, refresh the model, now the Entity Table should be OK, so delete the entity table again rename it back to the original name and refresh the model once more. This time everything should be fine.
I know this is a messed up procedure but this is the only way I found to fix this issue without blowing away the entire edmx and starting from scratch. Currently at my organization we have a policy not to make changes to the EDMX unless absolutely necessary so that we can delete and recreate when ever needed without any problems.
Hope this helps!