In spring managed transaction i save a object using criteria,
MyObject ob = ...
getCurrentSession.save(ob);
after some i need to execute a update(HQL) query and in all those updated rows i need to update MyObject reference(ob).
while i try this i got "integrity constrains, no parent key " exception.
As a solution i done below,
MyObject ob = ...
getCurrentSession.save(ob);
getCurreentSession.flush();
then execute the update query and pass ref:ob to that.
works fine. But the problem is if update returns 0, i need to rollback my transaction.
Note: i should not throw exception.
Since i am inside spring managed below are my approaches,
1) TransactionInterceptor.currentTransactionStatus().setRollbackOnly(). this did not work.
2) manually i deleted the persisted object. This works fine.
Just want to know that is there any way to rollback all my transaction?
Related
I have a simple Core Data entity Story that occasionally I update with the latest data from a network call. This network call sometimes updates many, many stories instances, so I run an NSBatchInsertRequest, shown below. (The other reason I'm using a batch insert is that many stories might need to be added to the persistent store.)
The problem is a user can have already marked a Story as a favorite. When they do that, I set story.isFavorite = true on the main thread and save viewContext.
However, when the batch insert occurs it overwrites story.isFavorite, setting it back to false, even though I'm using NSMergeByPropertyObjectTrumpMergePolicy on both the batch insert and view contexts. I am not touching story.isFavorite in the batch insert handler either so I don't expect that property to be overwritten.
I thought the benefit of a batch insert with this merge policy was to avoid first fetching + then manually updating changed properties + finally saving. What is the right way to avoid changing property values in an NSBatchInsertRequest?
Story
#objc(Story)
public class Story: NSManagedObject {
#NSManaged public var title: String?
#NSManaged public var storyURL: URL?
#NSManaged public var updatedTime: Date?
#NSManaged public var isFavorite: Bool // <- the problem property
}
Batch insert
container.viewContext.mergePolicy = NSMergeByPropertyObjectTrumpMergePolicy
container.viewContext.automaticallyMergesChangesFromParent = false
let context = NSManagedObjectContext(concurrencyType: .privateQueueConcurrencyType)
context.parent = container.viewContext
context.mergePolicy = NSMergeByPropertyObjectTrumpMergePolicy
context.perform {
let batchInsert = NSBatchInsertRequest(entity: Story.entity(), managedObjectHandler: { managedObject in
let story = managedObject as! Story
let storyResponse = downloadedStories[I]
// Update story with latest response data BUT don't modify story.isFavorite.
story.title = storyResponse.title
story.storyURL = storyResponse.storyURL
story.updatedTime = storyResponse.updatedTime
// ...
})
let result = try context.execute(batchInsert) as? NSBatchInsertResult
if let insertedIDs = result?.result as? [NSManagedObjectID] {
// Merge changes into parent context. Skip save() because not needed for batch insert.
NSManagedObjectContext.mergeChanges(fromRemoteContextSave: [NSInsertedObjectsKey: insertedIDs], into: [container.viewContext])
}
}
Edit
The Story entity does have a unique value constraint using attribute storyURL.
Update after Michael Tsai's answer
By making the Story entity attribute isFavorite a non-Optional Boolean without a default value (it was marked as Optional before, though I'm not sure it makes a difference here) and keeping the Use Scalar Type box checked, I can confirm that existing objects in the store will not be modified (at all) with this configuration of the batch insert context.
context.persistentStoreCoordinator = container.persistentStoreCoordinator
// HOWEVER, observe that regardless of the merge policy below,
// setting `context.parent = container.viewContext` will also
// overwrite the store data!
context.mergePolicy = NSMergeByPropertyStoreTrumpMergePolicy
// NSMergeByPropertyObjectTrumpMergePolicy ignores objects in the store
// (which have the same unique constraint value, here equal `storyURL`)
// and overwrites all properties.
// To confirm that the batch insert operation does not modify
// existing Story instances (at all), first delete all instances where
// where isFavorite == false. Then load the all story data again and
// execute the NSBatchInsertRequest with this change to managedObjectHandler:
story.title = storyResponse.title + " (modified)"
You will see the missing stories get inserted back, this time with their titles having a suffix " (modified)"; but previously favorited stories
do not get modified (basically, with this setup, the batch insert won't re-insert objects).
So the isFavorite property does not get overwritten BUT neither do any properties that should be changed (because they received a new title, for example).
Therefore, if you don't want your objects to get updated, but you want completely new objects to be inserted, you can use this approach.
However, if you are expecting your objects to require updates here are some alternatives:
you may opt to run a separate update operation, maybe an NSBatchUpdateRequest after you run your batch insert in this way,
or after the batch insert, you can update certain properties in a simple loop in a (possibly background/child) context without a batch operation, which could be fine if there isn't tons of data;
lastly, you might be able to first batch insert new data to a temporary store before somehow manually merging your choice of properties with the new store, then delete the temporary store.
A simpler approach: you could fetch the all properties you want to keep unchanged before you execute the batch insert (storing them in an dictionary keyed by your object's uniqueness constraint value), and then during the batch insert set the property again.
For this approach, you will want to use a different merge policy such as NSMergeByPropertyObjectTrumpMergePolicy so that the updated object gets re-inserted into the store (make sure to fetch all properties that you don't want to lose in advance of the batch insert)
random idea: How to Save Data When Using One ManagedObjectContext and PersistentStoreCoordinator with Two Stores
I don't think it is actually possible to do a partial update with a batch insert request. It's hard to know for sure because I don't think any of this is documented except in WWDC sessions. When I first watched the 2019 session, I was excited because the presenter said:
Attributes that are optional or configured with default values can be omitted from the dictionary as well.
In the case of updating an object with unique constraint, the existing values will not be changed.
I took this to mean that:
You can omit values for new objects, and you'll get the defaults or NULL. That makes sense.
If there's an existing object and you omit a value, that value will not the changed. So you can purposely omit values to do a partial update, i.e. update other values while leaving your isFavorite alone.
But, after writing code to test this and looking at the output from com.apple.CoreData.SQLDebug, what actually seems to happen with NSMergeByPropertyObjectTrumpMergePolicy is:
If you omit a value that's required you get a validation error.
If you omit a value that's optional, it updates the row to NULL. For a Bool property in Swift, this will become false.
If you omit a value with a default value, it updates the row to the default.
This is a shame because it seems like partial updates could be implemented by having the ON CONFLICT clause only specify DO UPDATE SET for the attributes that you actually set. But (as of macOS 11) Core Data seems to always generate SQL to set all of the columns.
In summary, with batch inserts, NSMergeByPropertyObjectTrumpMergePolicy does not actually merge by property based on what's changed (like with a regular Core Data save). Rather, it either inserts a new row (if the object is absent) or overwrites all the columns but preserves the objectID (if the object was present).
NSMergeByPropertyStoreTrumpMergePolicy also doesn't merge by property. It just means to leave the stored object alone if it's already present.
Update (2021-06-24): I heard from DTS that Apple considers the current (iOS 14/macOS 11) behavior described above a bug, and that it should let you batch insert without changing omitted properties. The Radar number is 79747419.
I want to update two database tables using hibernate entityManager. Currently I am updating 2nd table after verifying that data has been updated in 1st table.
My question is how to Rollback 1st table if data is not updated in 2nd table.
This is how I am updating individual table.
try {
wapi = getWapiUserUserAuthFlagValues(subject, UserId);
wapi.setFlags((int) flags);
entityManager.getTransaction().begin();
entityManager.merge(wapi);
entityManager.flush();
entityManager.getTransaction().commit();
} catch (NoResultException nre) {
wapi = new Wapi();
wapi.setSubject(merchant);
wapi.setUserId(UserId);
wapi.setFlags((int) flags);
entityManager.getTransaction().rollback();
}
Note - I am calling separate methods to update each table data
Thanks
I got the solution. basically I was calling two methods to update 2 db table and these two methods I am calling from one method.
Ex - I am method p and q from method r.
Initially I was calling begin, merge, flush and commit entitymanager methods in both p and q.
Now I am calling begin and commit in r and merge and flush in p and q.
So now my tables are getting updated together and rollback is also simple.
Hope it will help someone. Because I wasted my time for this, probably it can save someone else.
Thanks
I have multiple threads running a batch job. When each thread finishes it calls this method of mine:
private static readonly Object lockVar = new Object();
public void UserIsDone(int batchId, int userId)
{
//Get the batch user
var batchUser = context.ScheduledUsersBatchUsers.SingleOrDefault(x => x.User.Id == userId && x.Batch.Id == batchId);
if (batchUser != null)
{
lock (lockVar)
{
context.ScheduledUsersBatchUsers.Remove(batchUser);
context.SaveChanges();
//Try to get the batch with the assumption it has no users left. If we do get the batch back, it means there are no users left.
var dbBatch = context.ScheduledUsersBatches.SingleOrDefault(x => x.Id == batchId && !x.Users.Any());
//So this must have been the last user, the batch is empty, so we fetch it and remove it.
if (dbBatch != null)
{
context.ScheduledUsersBatches.Remove(dbBatch);
context.SaveChanges();
}
}
}
}
What this method does is very simple, it looks up the "BatchUser" to remove him from the queue, which it does. That part works swell.
However, after removing the user I want to check if that was the last user in the whole batch. But since this is multithreaded a race condition can happen.
So I put the removing of the batch user within a lock, after I remove the user, I check if the batch has no more batch users.
But here is my problem... even tho I have a lock, and the query to get the "dbBatch" clearly requires it to have no users to return the object... even so, I sometimes get it back with users like so:
When I do get that, I also get the following error on SaveChanges()
However, at other times I get the dbBatch object back correctly with no children, like so:
And when I do, it all works great, no exceptions.
With debugger I can catch the error by setting a breakpoint on the lock statement (see screenshot one). Then all threads get to the lock (while one goes in). Then I always get the error.
If I only have a breakpoint inside the if-statement it's more random.
With the lock in place, I don't see how this happens.
Update
I Ninject my context, and this is my ninject code
kernel.Bind<MyContext>()
.To<MyContext>()
.InRequestScope()
.WithConstructorArgument("connectionStringOrName", "MyConnection");
kernel.Bind<DbContext>().ToMethod(context => kernel.Get<MyContext>()).InRequestScope();
Update 2
I also tried this solution https://msdn.microsoft.com/en-us/data/jj592904.aspx
But strangely I don't get a DbUpdateConcurrencyException but rather I get a DbUpdateException that has an InnerException that is OptimisticConcurrencyException.
But neither DbUpdateException or OptimisticConcurrencyException contains a Entries property so I can't do ex.Entries.Single().Reload();
I'm also adding the exception in text form here
Here in text also, The outer exception of type DbUpdateException: {"An error occurred while saving entities that do not expose foreign key properties for their relationships. The EntityEntries property will return null because a single entity cannot be identified as the source of the exception. Handling of exceptions while saving can be made easier by exposing foreign key properties in your entity types. See the InnerException for details."}
The InnerException of type OptimisticConcurrencyException: {"Store update, insert, or delete statement affected an unexpected number of rows (0). Entities may have been modified or deleted since entities were loaded. See http://go.microsoft.com/fwlink/?LinkId=472540 for information on understanding and handling optimistic concurrency exceptions."}
I'm using an azure table query to retrieve all error entities assigned to a user.
Afther that I change a property of the entity to state that the entity is in processing mode.
After I have processed the entity I remove the entity from the table.
When I do parallel tests it can happen that during the query, an entity was already processed and deleted by another thread. So I get the error 404 ResourceNotFound when I want to Replace the entity.
Is there a way to test, if the entity was changed outside of the thread or if it still exists? Is it better to catch error 404 and ignore it or should I query for the entity again (seems all not right for me)?
TableQuery<ErrorObjectTableEntity> query = new TableQuery<ErrorObjectTableEntity>().Where(TableQuery.GenerateFilterCondition("PartitionKey", QueryComparisons.Equal, user));
List<ErrorObjectTableEntity> queryResult = table.ExecuteQuery(query).OrderBy(x => x.action).ToList();
foreach (ErrorObjectTableEntity entity in queryResult)
{
entity.inProcess = true;
try
{
TableOperation updateOperation = TableOperation.Replace(entity);
table.Execute(updateOperation);
}
catch
{
//..some logging here
//catch error 404?
}
//do some action
try
{
TableOperation deleteOperation = TableOperation.Delete(entity);
table.Execute(deleteOperation);
}
catch{...}
}
There are a couple of issues here as far as best practice. Your code as written could simply ignore the exception assuming another worker removed it but this could end up masking other classes of errors. One solution would be to use Queues to insert messages per user query, and then have various workers retrieve a message and process the query for a specific user. This way if a node goes down the app would absorb the fault and continue on. Additionally, this would keep your workers from duplicating work which would optimize the entire application. Lastly, if you don't care about the state of the entity and the keys are predictable you can use the Merge semantic to simply update a given property of an Entity without replacing the entire thing.
You should just catch the 404 error. Although they're represented as exceptions in .NET, HTTP 4xx error codes are more informational than exceptional. (5xx error codes are exceptional.)
Even if you checked that the entity existed before doing the replace, you would still need to catch the NotFound error in case it had been deleted between the check and the replace call. So you might as well skip the check.
I am using the following code to update an entity.
Service.Update(_policy);
where policy is a class generated using CrmSvcUtil.exe
public partial class new_policy : Microsoft.Xrm.Sdk.Entity, System.ComponentModel.INotifyPropertyChanging, System.ComponentModel.INotifyPropertyChanged
I retrieve the policies using LINQ, then update one attribute (an EntityReference) and then attempt the update
When this code runs I get the following error message:
EntityState must be set to null, Created (for Create message) or
Changed (for Update message)
There are other entities generated in the same way that I can update.
I tried
_policy.EntityState = EntityState.Changed
but then I get a message saying
The entity is read-only and the 'EntityState' property cannot be
modified. Use the context to update the entity instead.
Does anyone know what is causing this?
You have to tell your crmContext (use appropriate name) what to do with the changes.
You should add crmContext.UpdateObject(contact); before crmContext.SaveChanges();
See also How to update a CRM 2011 Entity using LINQ in a Plugin?
To avoid the problem you can simply use update-helper-objects instead of using the retrieved record:
var policyUpdater = new Policy { Id = _policy.Id, FieldToUpdate = "newValue" };
service.Update(policyUpdater);
Note: Properties of the update-helper-object that aren't set are simply ignored. The update won't set the corresponding record fields to null
I had the same problem. I switched from using
context.Update(object)
to
context.UpdateObject(object)
and it worked.
This worked for me:
recordToUpdate.EntityState = EntityState.Changed;
(recordToUpdate is an Entity to be updated)
Turns out it was an issue with my linq query that was retrieving the entity in the first place. When I replaced this with a query expression it worked okay.
Time to brush up on my linq!