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0

Is there a way to create the reference of the child in a method but persist the child entity in a different method?

Right now, I am creating the reference first and then persisting the child in the same method. Only after this is being done, the parent is persisted. If DatastoreTimeoutException, ConcurrentModificationException, or DatastoreFailureException occurs during saving parent entity, I am left with child entity persisted in datastore which is of no use.

@Entity
@Index
public class parentEntity
 

@Id
private String uniqueIdentifier;
private String name = new String();
@Load
private LinkedList <Ref <childEntity>> refToChild = new LinkedList <Ref <childEntity>>();

 

@Entity
@Index
public class childEntity
 

@Id
private String uniqueIdentifier;
private String address = new String();
@Load
@Parent
public Ref <parentEntity> refToParent;

 

This method first creates the reference parent has with child and then persists the entity(child)

public static void createRefAndSaveChildEntity()

 Ref.create( key ) ;//creates the reference with child
 ofy().save().entity( childEntity ).now(); 
 

I want to persist the child only after the parent(with reference to child) is being persisted.

java google-cloud-datastore objectify

share|improve this question

asked Mar 28 at 7:17

Hanok JacobHanok Jacob

633 bronze badges

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  why would you want to link to an object that doesn't exist yet? what if there's a problem persisting the child entity?
  
  – Stultuske
  Mar 28 at 7:18
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Given that you are using a parent-child relationship, you should be able to use an ancestor query to retrieve the children instead of keeping an explicit reference to the child entities in the parent entity.
  
  – Jim Morrison
  Mar 28 at 16:49
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @Stultuske yeah, coming to think of it, a problem could arise when persisting the child.
  
  – Hanok Jacob
  Apr 5 at 13:52
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @JimMorrison, yeah for querying i could, but how to do while saving?
  
  – Hanok Jacob
  Apr 5 at 13:53
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  What I was saying is that you don't need to keep an explicit reference because you have an implicit reference through ancestor queries.
  
  – Jim Morrison
  Apr 6 at 16:04
  

  
  
  
  

add a comment | 

0

Is there a way to create the reference of the child in a method but persist the child entity in a different method?

Right now, I am creating the reference first and then persisting the child in the same method. Only after this is being done, the parent is persisted. If DatastoreTimeoutException, ConcurrentModificationException, or DatastoreFailureException occurs during saving parent entity, I am left with child entity persisted in datastore which is of no use.

@Entity
@Index
public class parentEntity
 

@Id
private String uniqueIdentifier;
private String name = new String();
@Load
private LinkedList <Ref <childEntity>> refToChild = new LinkedList <Ref <childEntity>>();

 

@Entity
@Index
public class childEntity
 

@Id
private String uniqueIdentifier;
private String address = new String();
@Load
@Parent
public Ref <parentEntity> refToParent;

 

This method first creates the reference parent has with child and then persists the entity(child)

public static void createRefAndSaveChildEntity()

 Ref.create( key ) ;//creates the reference with child
 ofy().save().entity( childEntity ).now(); 
 

I want to persist the child only after the parent(with reference to child) is being persisted.

java google-cloud-datastore objectify

share|improve this question

asked Mar 28 at 7:17

Hanok JacobHanok Jacob

633 bronze badges

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  why would you want to link to an object that doesn't exist yet? what if there's a problem persisting the child entity?
  
  – Stultuske
  Mar 28 at 7:18
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Given that you are using a parent-child relationship, you should be able to use an ancestor query to retrieve the children instead of keeping an explicit reference to the child entities in the parent entity.
  
  – Jim Morrison
  Mar 28 at 16:49
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @Stultuske yeah, coming to think of it, a problem could arise when persisting the child.
  
  – Hanok Jacob
  Apr 5 at 13:52
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @JimMorrison, yeah for querying i could, but how to do while saving?
  
  – Hanok Jacob
  Apr 5 at 13:53
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  What I was saying is that you don't need to keep an explicit reference because you have an implicit reference through ancestor queries.
  
  – Jim Morrison
  Apr 6 at 16:04
  

  
  
  
  

add a comment | 

Is there a way to create the reference of the child in a method but persist the child entity in a different method?

Right now, I am creating the reference first and then persisting the child in the same method. Only after this is being done, the parent is persisted. If DatastoreTimeoutException, ConcurrentModificationException, or DatastoreFailureException occurs during saving parent entity, I am left with child entity persisted in datastore which is of no use.

@Entity
@Index
public class parentEntity
 

@Id
private String uniqueIdentifier;
private String name = new String();
@Load
private LinkedList <Ref <childEntity>> refToChild = new LinkedList <Ref <childEntity>>();

 

@Entity
@Index
public class childEntity
 

@Id
private String uniqueIdentifier;
private String address = new String();
@Load
@Parent
public Ref <parentEntity> refToParent;

 

This method first creates the reference parent has with child and then persists the entity(child)

public static void createRefAndSaveChildEntity()

 Ref.create( key ) ;//creates the reference with child
 ofy().save().entity( childEntity ).now(); 
 

I want to persist the child only after the parent(with reference to child) is being persisted.

java google-cloud-datastore objectify

share|improve this question

asked Mar 28 at 7:17

Hanok JacobHanok Jacob

633 bronze badges

@Entity
@Index
public class parentEntity
 

@Id
private String uniqueIdentifier;
private String name = new String();
@Load
private LinkedList <Ref <childEntity>> refToChild = new LinkedList <Ref <childEntity>>();

 

@Entity
@Index
public class childEntity
 

@Id
private String uniqueIdentifier;
private String address = new String();
@Load
@Parent
public Ref <parentEntity> refToParent;

 

This method first creates the reference parent has with child and then persists the entity(child)

public static void createRefAndSaveChildEntity()

 Ref.create( key ) ;//creates the reference with child
 ofy().save().entity( childEntity ).now(); 
 

share|improve this question

asked Mar 28 at 7:17

Hanok JacobHanok Jacob

633 bronze badges

share|improve this question

asked Mar 28 at 7:17

Hanok JacobHanok Jacob

633 bronze badges

asked Mar 28 at 7:17

Hanok JacobHanok Jacob

633 bronze badges

asked Mar 28 at 7:17

Hanok JacobHanok Jacob

633 bronze badges