With EF, any data value in Entity instance can be saved back to database by calling SaveChanges which can be overridden to add custom action.
So I try to override SaveChanges in following way:
public override int SaveChanges(System.Data.Objects.SaveOptions options)
{
try
{
return base.SaveChanges(options);
}
catch (Exception ex)
{
//error log here
//write the error message to database table errorlog
throw ex;
}
}
when SaveChange failed, I want to grab the exception and save the error message to a table in same database. With about code, even save data to table errorlog, also should call SaveChanges. How to resolve this problem?
Initialize a new context instance in your catch block and log the error.
public override int SaveChanges(System.Data.Objects.SaveOptions options)
{
try
{
return base.SaveChanges(options);
}
catch (Exception ex)
{
var context = new MyContext();
// your log class instance populated with relevant details
var error = new Error { Message = ex.Message; };
context.Errors.AddObject(error);
context.SaveChanges();
throw;
}
}
In addition to #Eranga's advice use separate context type just for error logging (it will map only Error entity). This new context type will not have overriden SaveChanges - that will avoid infinite loop in case of error fired during error saving.
Related
I would like to rollback a transaction for the data in case of errors and at the same time write the error to db.
I can't manage to do with Transactional Annotations.
Following code produces a runtime-error (1/0) and still writes the data into the db. And also writes the data into the error table.
I tried several variations and followed similar questions in StackOverflow but I didn't succeed to do.
Anyone has a hint, how to do?
#Service
public class MyService{
#Transactional(rollbackFor = Exception.class)
public void updateData() {
try{
processAndPersist(); // <- db operation with inserts
int i = 1/0; // <- Runtime error
}catch (Exception e){
persistError()
trackReportError(filename, e.getMessage());
}
}
#Transactional(propagation = Propagation.REQUIRES_NEW)
public void persistError(String message) {
persistError2Db(message); // <- db operation with insert
}
You need the way to throw an exception in updateData() method to rollback a transaction. And you need to not rollback persistError() transaction at the same time.
#Transactional(rollbackFor = Exception.class)
public void updateData() {
try{
processAndPersist(); // <- db operation with inserts
int i = 1/0; // <- Runtime error
}catch (Exception e){
persistError()
trackReportError(filename, e.getMessage());
throw ex; // if throw error here, will not work
}
}
Just throwing an error will not help because persistError() will have the same transaction as updateData() has. Because persistError() is called using this reference, not a reference to a proxy.
Options to solve
Using self reference.
Using self injection Spring self injection for transactions
Move the call of persistError() outside updateData() (and transaction). Remove #Transactional from persistError() (it will not work) and use transaction of Repository in persistError2Db().
Move persistError() to a separate serface. It will be called using a proxy in this case.
Don't use declarative transactions (with #Transactional annotation). Use Programmatic transaction management to set transaction boundaries manually https://docs.spring.io/spring-framework/docs/3.0.0.M3/reference/html/ch11s06.html
Also keep in mind that persistError() can produce error too (and with high probability will do it).
Using self reference
You can use self reference to MyService to have a transaction, because you will be able to call not a method of MyServiceImpl, but a method of Spring proxy.
#Service
public class MyServiceImpl implements MyService {
public void doWork(MyService self) {
DataEntity data = loadData();
try {
self.updateData(data);
} catch (Exception ex) {
log.error("Error for dataId={}", data.getId(), ex);
self.persistError("Error");
trackReportError(filename, ex);
}
}
#Transactional
public void updateData(DataEntity data) {
persist(data); // <- db operation with inserts
}
#Transactional
public void persistError(String message) {
try {
persistError2Db(message); // <- db operation with insert
} catch (Exception ex) {
log.error("Error for message={}", message, ex);
}
}
}
public interface MyService {
void doWork(MyService self);
void updateData(DataEntity data);
void persistError(String message);
}
To use
MyService service = ...;
service.doWork(service);
I'm using EF Core and Devart's data provider library. I've hit an issue I can't figure out with handling user input errors smoothly. The error seems to be limited to adding a new entity to the context.
Scenario
User inputs an invalid value in a field.
Save changes is called and throws then displays error.
Prompt user to fix the error.
After this if the error is fixed and save is called again (this is good data now), I get an exception "Transaction already exists" from the Devart data provider library.
StackTrace
at Devart.Data.Oracle.OracleConnection.BeginTransaction(IsolationLevel il)
at Devart.Data.Oracle.OracleConnection.BeginDbTransaction(IsolationLevel isolationLevel)
at System.Data.Common.DbConnection.BeginTransaction(IsolationLevel isolationLevel)
at .BeginDbTransaction(IsolationLevel )
at System.Data.Common.DbConnection.BeginTransaction(IsolationLevel isolationLevel)
at Microsoft.EntityFrameworkCore.Storage.RelationalConnection.BeginTransactionWithNoPreconditions(IsolationLevel isolationLevel)
at Microsoft.EntityFrameworkCore.Storage.RelationalConnection.BeginTransaction(IsolationLevel isolationLevel)
at Microsoft.EntityFrameworkCore.Storage.RelationalConnection.BeginTransaction()
at Microsoft.EntityFrameworkCore.Infrastructure.DatabaseFacade.BeginTransaction()
at
I tried to break out the transaction and handle it manually MSDN Transactions but I still get the same error.
public bool SaveAllChanges()
{
var result = false;
using (var transaction = _context.Database.BeginTransaction())
{
try
{
_context.Database.AutoTransactionsEnabled = false;
_context.SaveChanges(true);
transaction.Commit();
result = true;
}
catch (Exception exc)
{
InvokeError(exc, "Error saving changes.");
result = false;
}
}
_context.Database.AutoTransactionsEnabled = true;
_context.Database.CloseConnection();
return result;
}
How do I recover from a db error without scrapping all of the user's input? I would hate for that to be practice. I could be validating all the data going in but recovering from simple errors would be better.
After fussing around with this I found the magic sauce. This type of error only seems to come up when adding an object to the DB. It's as if the context doesn't dispose of the transaction on fail.
public bool SaveAllChanges()
{
var result = false;
_context.Database.AutoTransactionsEnabled = false;
using (var transaction = _context.Database.BeginTransaction())
{
try
{
_context.SaveChanges(true);
transaction.Commit();
result = true;
}
catch (Exception exc)
{
transaction.Rollback(); <-------- Here.
InvokeError(exc, "Error saving changes.");
result = false;
}
}
_context.Database.AutoTransactionsEnabled = true;
_context.Database.CloseConnection();
return result;
}
If someone has a solution to where I don't need to handle the transaction in this way please post it.
We cannot reproduce the "Transaction already exists" exception with the following code:
using (var _context = new MyContext())
{
var entity = new MyEntity() { ID = 10, Name = "entry exceeds max length of the field" };
_context.MyEntities.Add(entity);
try
{
_context.SaveChanges(true); // error
}
catch (Exception ex)
{
//InvokeError(exc, "Error saving changes.");
}
entity.Name = "correct input";
_context.SaveChanges(); // success
}
Please localize the issue in a small application and send us this project for reproducing.
Have a list of data need to be saved. Before the save had to delete the existing data and save the new data.
If any of the delete & save is failed that transaction need to roll back, rest of the delete & save transaction should continue.
public LabResResponse saveLabResult(List<LabResInvstResultDto> invstResults) {
LabResResponse labResResponse = new LabResResponse();
List<Long> relInvstid = new ArrayList<Long>();
try{
if(invstResults != null){
List<LabResInvstResult> labResInvstResults = mapper.mapAsList(invstResults, LabResInvstResult.class);
for(LabResInvstResult dto: labResInvstResults){
if(dto != null){
//delete all child records before save.
deleteResult(dto, relInvstid);
}
}
}
labResResponse.setRelInvstids(relInvstid);
}catch(Exception e){
e.printStackTrace();
}
return labResResponse;
}
Here new transaction will added for each delete & save
#Transactional(propagation = Propagation.REQUIRES_NEW, rollbackFor = { Exception.class })
private void deleteResult(LabResInvstResult dto, List<Long> relInvstid) {
try{
labResultRepo.deleteById(dto.getId());
LabResInvstResult result = labResultRepo.save(dto);
}catch(Exception e){
e.printStackTrace();
}
}
On delete it throws an exception "Caused by: javax.persistence.TransactionRequiredException: No EntityManager with actual transaction available for current thread - cannot reliably process 'remove' call"
I can solve this by adding a #Transactional for public LabResResponse saveLabResult(List invstResults) method.
But my intial usecase will not work this will roll back entire list of transaction.
Here are two problems.
The first problem is that you call the "real" deleteResult method of the class. When Spring sees #Transactional it creates a proxy object with transactional behavior. Unless you're using AspectJ it won't change the class itself but create a new one, proxy. So when you autowire this bean you will be able use proxy's method that runs transaction related logic. But in your case you're referencing to the method of the class, not proxy.
The second problem is that Spring (again if AspectJ is not used) can't proxy non-public methods.
Summary: make the deleteResult method public somehow and use proxied one. As a suggestion, use another component with deleteResult there.
You are catching exception out of for loop, while your requirement says you want to continue the loop for other objects in list.
Put your try/catch block with-in loop. It should work fine
public LabResResponse saveLabResult(List<LabResInvstResultDto> invstResults) {
LabResResponse labResResponse = new LabResResponse();
List<Long> relInvstid = new ArrayList<Long>();
try{
if(invstResults != null){
List<LabResInvstResult> labResInvstResults = mapper.mapAsList(invstResults, LabResInvstResult.class);
for(LabResInvstResult dto: labResInvstResults){
if(dto != null){
//delete all child records before save.
try {
deleteResult(dto, relInvstid);
} catch(Exception e){
e.printStackTrace();
}
}
}
}
labResResponse.setRelInvstids(relInvstid);
}catch(Exception e){
e.printStackTrace();
}
return labResResponse;
}
God day!
I have a tree of entities and at specific point of time i need to update only scalar properties of one entity. Classic update rise entire graph lookup, but relations not need to update.
The trouble in Category entity what one category have another categories in children. My method generate exceptions when saving changes about duplicate key. I think EF try to add children to database.
Static method of my data context listed below:
public static void Update<T>(T item) where T : KeyedObject
{
if (item == null)
throw new ArgumentNullException("Item to update is null");
item.ValidateIsNotNew();
using (DataContext db = new DataContext())
{
T original = GetOriginalWithException<T>(db, item);
DbEntityEntry entry = db.Entry(original);
entry.CurrentValues.SetValues(item);
entry.State = EntityState.Modified;
try
{
db.SaveChanges();
}
catch (Exception ex)
{
throw new DatabaseException(
"Cant update list item. See inner exception for details.",
ex);
}
}
}
I tries another method: attaching object. This method does not throw exception, but it rise entire graph update and take many resources. Code listed below:
public static void Update<T>(T item) where T : KeyedObject
{
if (item == null)
throw new ArgumentNullException("Item to update is null");
item.ValidateIsNotNew();
using (DataContext db = new DataContext())
{
db.Set<T>().Attach(item);
db.Entry(item).State = EntityState.Modified;
try
{
db.SaveChanges();
}
catch (Exception ex)
{
throw new DatabaseException(
"Cant update list item. See inner exception for details.",
ex);
}
}
}
I am using EJB 3.0 timer.When my Timeout method gets invoked,I use JPA to insert a record in one of the table.I use JPA to persist the data.I defined the persist code in a Stateless Session Bean and invoked the local interface inside my timeout method.I get the following exception when the thread comes out of the timeout method:
javax.transaction.xa.XAException: JDBC driver does not support XA, hence cannot be a participant in two-phase commit.
To force this participation, set the GlobalTransactionsProtocol attribute to LoggingLastResource (recommended) or EmulateTwoPhaseCommit for the Data Source
Our DB does not support XA transaction.We use WL 10.3.1.Here is the code which i do :
#EJB
private MyejbLocal myejbLocal
#Timeout
public void callEjb(timer) {
try {
myejbLocal .store();
} catch (EntityExistsException e) {
e.getMessage();
} catch (Exception ex) {
ex.getCause();
}
}
Here is my implementation:
#Override
public void Store() {
try {
Mytable mytable= new Mytable (new Date());
persist(mytable);
} catch (EntityExistsException e) {
e.getMessage();
} catch (Exception ex) {
ex.getCause();
}
}
I don't call flush() method.
Please let me know if I have missed any?
I also faced the same issue. You need to keep your JPA entity operation in a separate session bean and it will work.
http://prasunejohn.blogspot.in/2014/02/understanding-ejb-timer-service-31.html