I'm facing this exception An attempt has been made to Attach or Add an entity that is not new, perhaps having been loaded from another DataContext. This is not supported. when I try to insert a new entity into my Employees table (the master one).
There is a relationship between the master Employees table and the details Orders table, and I'm sure that the relationship between these two tables (and specifically Employee.Orders EntitySet) is the cause of the problem since when I removed the relationship, it returns back to insert into Employees table with no problems.
When I searched for the problem, there was this blog post which I tried to implement but my case is a different than the one in the blog post in these items:
He faces the exception when tries to update (while I try to insert).
The tables architecture is different.
how can I solve this problem?
Here's the insertion code:
Employee emp = new Employee();
emp.Name = empName; // empName is a local variable
// What should I default emp.Orders to?
dc.Employees.InsertOnSubmit(emp);
dc.SubmitChanges();
P.S: My DataContext is defined on class-level in my repository and the exception is being thrown when I call dc.SubmitChanges();. and I didn't Attach any object why does it say that?
Here is an article explaining what you need to do using the Attach and Detach methods:
http://www.codeproject.com/KB/linq/linq-to-sql-detach.aspx
I am guessing it is trying to save something else besides just the employee object or you aren't showing us the full code in your repository. When you instantiate your DataContext object (dc) try setting DeferredLoadingEnabled = false, and ObjectTrackingEnabled = false and see if it works. If it does, try watching the SQL code in SQL Server Profiler and see if it is modifying other objects that may have came from a different context like the message says.
var dc = new MyDataContext()
{
DeferredLoadingEnabled = false,
ObjectTrackingEnabled = false
};
My bet is on the primary key.
Are you sure the primary key is also set on auto increment?
Did you
try changing the name, does it work then?
What happens if you remove
all rows from your DB? can you insert one then?
Related
I would like to use Umbraco Forms to not only insert data but to edit it as well. So far when I want to edit a record I am passing in the form guid and the record id via querystring and populating the correct data in the fields.
So far so good.
I am then hooking in to the Umbraco.Forms.Data.Storage.RecordStorage.RecordInserting event successfully like so
void RecordStorage_RecordInserting(object sender, Umbraco.Forms.Core.RecordEventArgs e)
{
var ms = (Umbraco.Forms.Data.Storage.RecordStorage)sender;
if(this record exists){
ms.UpdateRecord(e.Record, e.Form);
}
}
However when I try to submit an edited record, and the ms.RecordUpdate(e.Record, e.Form) line runs I get this error
The INSERT statement conflicted with the FOREIGN KEY constraint "FK_UFRecordDataString_UFRecordFields_Key". The conflict occurred in database "UmbracoPlay", table "dbo.UFRecordFields", column 'Key'.
The statement has been terminated.
I can't delete the old record and then insert a new record because it will re raise the same event everytime I call ms.InsertRecord
What am I missing?
How can I use Umbraco Forms to edit existing data?
I couldn't see a fix for this bug- it appears as though the UpdateRecord method actually tries to insert all UFRecordField objects a second time rather than updating the existing values ( or the existing field values ) resulting in this key violation.
If you really need to work around this - as I did - then one thing that works ( but leaves you with somewhat more fragmented primary keys ) is simply to remove and then reinsert the form data:
var ms = (Umbraco.Forms.Data.Storage.RecordStorage)sender;
if(this record exists){
ms.DeleteRecord(e.Record, e.Form);
ms.InsertRecord(e.Record, e.Form);
}
An untidy solution, but seemingly effective.
I am new to learning and understanding how Hydration works, just wanted to point that out first. I'm currently able to Hydrate Select and Insert queries without any problems.
I am currently stuck on trying to Hydrate Update queries now. In my entity I have setup the get/set options for each type of column in my database. I've found that the ObjectProperty() Hydrator works best for my situation too.
However whenever I try to update only a set number of columns and extract via the hydrator I am getting errors because all the other options are not set and are returning null values. I do not need to update everything for a particular row, just a few columns.
For example in my DB Table I may have:
name
phone_number
email_address
But I only need to update the phone_number.
$entity_passport = $this->getEntityPassport();
$entity_passport->setPrimaryPhone('5551239876');
$this->getTablePassport()->update($this->getHydrator()->extract($entity_passport), array(
'employeeid' => '1'
));
This returns an error because setName() and setEmailAddress() are not included in this update and the query returns that the values cannot be null. But clearly when you look at the DB Table, there is data already there. The data that is there does not need to be changed either, only in this example does the PrimaryPhone() number.
I've been looking and reading documentation all over the place but I cannot find anything that would explain what I am doing wrong. I should note that I am only using Zend\Db (Not Doctrine).
I'm assuming I've missed something someplace due to my lack of knowledge with this new feature I'm trying to understand.
Perhaps you don't Hydrate Update queries... I'm sort of lost / confused. Any help would be appreciated. Thank you!
I think you're having a fundamental misconception of hydration. A hydrator simply populates an entity object from data (hydrate) and extracts data from an entity object (extract). So there are no separate hydrators for different types of queries.
In your update example you should first retrieve the complete entity object ($entity_passport) and then pass it to the TableGateway's update method. You would retrieve the entity by employeeid, since that's the condition you're using to update. So something like this:
$entity_passport = $passportMapper->findByEmployeeId(1);
$entity_passport->setPrimaryPhone('5551239876');
$this->getTablePassport()->update($this->getHydrator()->extract($entity_passport), array(
'employeeid' => $entity_passport->getId()
));
This is assuming you have some sort of mapper layer. Otherwise you could use your passport TableGateway (I assume that's what getTablePassport() returns, no?).
Otherwise, if you think retrieving the object is too much overhead and you just want to run the query you could use just a \Zend\Db\Sql\Sql object, ie:
$sql = new \Zend\Db\Sql\Sql($dbAdapter);
$update = $sql->update('passport')
->set(array('primary_phone' => $entity_passport->getPrimaryPhone()))
->where(array('employeeid' => $employeeId));
Edit:
Maybe it was a mistake to bring up the mapper, because it may cause more confusion. You could simply use your TableGateway to retrieve the entity object and then hydrate the returned row:
$rows = $this->getTablePassport()->select(array('employeeid' => 1));
$entity_passport = $this->getHydrator($rows->current());
[...]
Edit 2:
I checked your gist and I noticed a few things, so here we go:
I see that your getTablePassport indeed does return an object which is a subclass of TableGateway. You have already set up this class for it to use a HydratingResultset. This means you don't need to do any manual hydrating when retrieving objects using the gateway.
You also already implemented a Search method in that same class, so why not just use that? However I would change that method, because right now you're using LIKE for every single column. Not only is it very inefficient, but it will also give you wrong results, for example on the id column.
If you were to fix that method then you can simply call it in the Service object:
$this->getTablePassport->Search(array('employeeid' => 1));
Otherwise you could just implement a separate method in that tablegateway class, such as
public function findByEmployeeId($employeeId)
{
return $tableGateway->select(array('employeeid' => $employeeId));
}
This should already return an array of entities (or one in this specific case). P.S. make sure to debug and check what is actually being returned when you retrieve the entity. So print_r the entity you get back from the PassportTable before trying the update. You first have to make sure the retrieval code works well.
While updating with the help of LINQ to SQL using Entity Framework, an exception is thrown.
System.Data.UpdateException: Unable to update the EntitySet 't_emp' because it has
a DefiningQuery and no <UpdateFunction> element exists in the
<ModificationFunctionMapping>
The code for update is :
public void Updateall()
{
try
{
var tb = (from p in _te.t_emp
where p.id == "1"
select p).FirstOrDefault();
tb.ename = "jack";
_te.ApplyPropertyChanges(tb.EntityKey.EntitySetName, tb);
_te.SaveChanges(true);
}
catch(Exception e)
{
}
}
Why am I getting this error?
The problem was in the table structure. To avoid the error we have to make one primary key in the table. After that, update the edmx. The problem will be fixed
Three things:
Don't catch exceptions you can't handle. You're catching every exception possible, and then doing nothing with it (except swallowing it). That's a Bad Thing™ Do you really want to silently do nothing if anything goes wrong? That leads to corrupted state that's hard to debug. Not good.
Linq to SQL is an ORM, as is Entity Framework. You may be using LINQ to update the objects, but you're not using Linq to SQL, you're using Entity Framework (Linq to Entities).
Have you tried the solution outlined here? The exception you posted is somewhat cut off, so I can't be sure it's exactly the same (please update your post if it isn't), and if it is the same, can you comment on whether or not the following works for you?
"[..] Entity Framework doesn't know whether a given view is updatable
or not, so it adds the <DefiningQuery> element in order to safeguard
against having the framework attempt to generate queries against a
non-updatable view.
If your view is updatable you can simply remove the <DefiningQuery>
element from the EntitySet definition for your view inside of the
StorageModel section of your .edmx, and the normal update processing
will work as with any other table.
If your view is not updatable, you will have to provide the update
logic yourself through a "Modification Function Mapping". The
Modification Function Mapping calls a function defined in the
StorageModel section of your .edmx. That Function may contain the
name and arguments to a stored procedure in your database, or you can
use a "defining command" in order to write the insert, update, or
delete statement directly in the function definition within the
StorageModel section of your .edmx." (Emphasis mine, post formatted for clarity and for Stack Overflow)
(Source: "Mike" on MSDN)
But You can Set primary Key in Model if use MVC Asp.net
Just Open model.edmx in your table ,go to your field property and set Entity Key = True
I have a POCO entity Report with a collection of a related POCO entity Reference. When creating a Report I get an ICollection<int> of ids. I use this collection to query the reference repository to get an ICollection<Reference> like so:
from r in referencesRepository.References
where viewModel.ReferenceIds.Contains(r.Id)
select r
I would like to connect the collection straight to Report like so:
report.References = from r in referencesRepository.References
where viewModel.ReferenceIds.Contains(r.Id)
select r;
This doesn't work because References is an ICollection and the result is an IEnumerable. I can do ToList(), but I think I will then load all of the references into memory. There also is no AddRange() function.
I would like to be able to do this without loading them into memory.
My question is very similar to this one. There, the only solution was to loop through the items and add them one by one. Except in this question the list of references does not come from the database (which seemed to matter). In my case, the collection does come from the database. So I hope that it is somehow possible.
Thanks in advance.
When working with entity framework you must load objects into memory if you want to work with them so basically you can do something like this:
report.References = (from r in referencesRepository.References
where viewModel.ReferenceIds.Contains(r.Id)
select r).ToList();
Other approach is using dummy objects but it can cause other problems. Dummy object is new instance of Reference object which have only Id set to PK of existing object in DB - it will act like that existing object. The problem is that when you add Report object to context you must manually set each instance of Reference in ObjectStateManager to Unchanged state otherwise it will insert it to DB.
report.References = viewModel.ReferenceIds.Select(i => new Reference { Id = i }).ToList();
// later in Report repository
context.Reports.AddObject(report);
foreach (var reference in report.References)
{
context.ObjectStateManager.ChangeObjectState(reference, EntityState.Unchanged);
}
I want to include a table (Events) from another database in my LINQ to SQL class.
How should I format the Data Source of that table?
I have tried with IP.dbo.Events, IP.DatabaseName.dbo.Events and so on, but can not get it to work.
The reason for all this is to select Events that a Client have attended.
I have also tried to have the table in another LINQ to SQL class, but then it complains on the Data Context.
public static IQueryable<Event> ByClientID(this IQueryable<Event> events, int clientID)
{
events = from e in events
from c in new MyDataContext().ClientCourses
where e.EventID == c.CourseID &&
c.ClientID == clientID
select e;
return events;
}
You can only use tables that reside on the same physical SQL Server in two different instances. I did this once as someone had "cleverly" put an application's DB across two database instances.
There is a blog post on it here that may help.
Could you create a view that returns the data from the 2nd database and use this instead? (Not tried this so absolutely no idea if it'll work :)
Obviously this is no good if you need to be saving to the other database too..