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Thank’s.
I will keep my model with the to-Many relationship, remove the class property…
…and (re)ceate all the methods to fetch objects, check when deleting et optimize the access to such a lists.
I'll start with the customers class and keep you informed,
Le 6 juin 2016 à 19:21, Ken Anderson < email@hidden> a écrit :
One other reason - non class property relationships help EOF resolve abstract entity relationships when prefetching. Without the non-class property back pointing relationships, the prefetched sub-entities don’t get connected properly.
On Jun 6, 2016, at 12:58 PM, Chuck Hill < email@hidden> wrote:
Relationships that are a class property are fetched and maintained by EOF. Relationships that are not a class property are just names that you can use in a fetch specification – it tells EOF how
to navigate the joins but EOF will not fetch or manage them.
Chuck
According to yours posts, it seems that for performance reasons, we have to think twice (or more) before adding a reverse to Many relationship.
Before removing all the non-usefull to Many relationships and add the associated delete controls, I have one more question (sic) :
- What’s the difference, in an EOModel, between a to Many relationship without Class Property and a to Many relationship with Class Property ?
(or : Is it worth keeping them or is it better deleting all of them)
Le 6 juin 2016 à 14:48, Samuel Pelletier < email@hidden> a écrit :
You can keep a cache of the results inside your EO. As the EO is specific to an EOEditingContext, it will be refreshed often if you use the pattern of creating a new EOEditingContext per main WOComponent.
BTW, the toMany is triggered by the fact we ask EOF to update the reverse relationships. By using an EO in a toOne, we add this EO to the reverse toMany, to add an object to an array, this array needs to exists.
Le 5 juin 2016 à 18:49, Jérémy DE ROYER < email@hidden> a écrit :
I tried this way last week but if it's faster when saving, it is much slower when reading because it fetches each time without caching...
The reading performances are really good but I have to find a way to speed up when inserting new objects that "overuse" the database and slow down the other users
Jeremy
That is what I meant by fetching. You need to re-implement those methods. Change it to do an fetch on Customer where modeTransport == this
You can still use it to fetch a ModeTransport based on “listOrder contains order”.
From: Jérémy DE ROYER <email@hidden>
Date: Sunday, June 5, 2016 at 3:26 PM
To: Chuck Hill <email@hidden>
Cc: WebObjects-Dev <email@hidden>
Subject: Re: How to avoid expensive fetches in database when setting to-one-relationship
What do you mean with « you can still use it for fetching » ?
I removed the class property for the Customer to Order (but keeped the « listOrder » relationship)
When I set the customer to the order, it runs fast.
But when I retrieve the orders using the method below :
public NSArray<Customer> listOrder() {
return (NSArray<Customer>)storedValueForKey("listOrder");
<com.webobjects.foundation.NSKeyValueCoding$UnknownKeyException message
‘<Customer 0x72c7423b> valueForKey(): lookup of unknown key: 'listOrder'.
This class does not have an instance variable of the name listOrder or _listOrder, nor a method of the name listOrder _listOrder, getListOrder, or _getListOrder' object ‘{...}'
key 'listOrder'>
at com.webobjects.foundation.NSKeyValueCoding$DefaultImplementation.handleQueryWithUnboundKey(NSKeyValueCoding.java:1377)
at com.webobjects.eocontrol.EOCustomObject.handleQueryWithUnboundKey(EOCustomObject.java:1545)
at com.webobjects.foundation.NSKeyValueCoding$Utility.handleQueryWithUnboundKey(NSKeyValueCoding.java:494)
at com.webobjects.foundation.NSKeyValueCoding$_KeyBinding.valueInObject(NSKeyValueCoding.java:894)
at com.webobjects.eocontrol.EOCustomObject.storedValueForKey(EOCustomObject.java:1634)
at Customer.listeOrder(_Customer.java:890)
Remove the “class property” setting for the ModeTransport to Order. You can still use it for fetching.
In our app, we have a one to many relationship between order and mode transport
For each order, we set the mode transport using the method below :
public void setModeTransportRelationship(ModeTransport
value) {
if (_CommandeClient.LOG.isDebugEnabled())
{
_CommandeClient.LOG.debug("updating modeTransport from " +
modeTransport() + " to " + value);
ModeTransport oldValue = modeTransport();
removeObjectFromBothSidesOfRelationshipWithKey(oldValue, "modeTransport");
addObjectToBothSidesOfRelationshipWithKey(value, "modeTransport");
Then, an objectWillChange() is fired for the mode transport… but the (not wished) consequence is that every to many relationships from the mode transport are fetched (even if we don’t call the associated method for the mode transport). However,
the objects associated with the to one relationships are not fetched.
We observed the same behavior for the customer object when using the setCustomerRelationship method of the ordre. The (bigger) problem is that the customer object has dozen of to many relationships... fetched for nothing…
At the beginning we had few orders but now, we have to wait from 10 to 30 seconds until de saveChange is ended and that’s really not effective. More than 90 % of this time is spent for fetching the to many relationship whereas we just had to save the order
values...
Any idea how to deal with theses not-wished-fetches ?
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