lazy-loading

问题 I currently mark collections in entity beans as eager to avoid getting a lazy initialization exception when I try to access the collection properties after loading the bean with the EntityManager. If I instead leave the collection as lazy loading, how do I keep a session open? I thought about trying @Transactional, but even if that worked I wouldn't want to do it because it doesn't seem right to leave a transaction open over a long method. 回答1: https://www.hibernate.org/43.html Basically, you

问题 I read here that Django querysets are lazy, it won't be evaluated until it is actually printed. I have made a simple pagination using the django's built-in pagination. I didn't realize there were apps already such as "django-pagination", and "django-endless" which does that job for. Anyway I wonder whether the QuerySet is still lazy when I for example do this entries = Entry.objects.filter(...) paginator = Paginator(entries, 10) output = paginator.page(page) return HttpResponse(output) And

问题 I'm starting to use cakePhp to make a small website. I defined relationship between table, and I want to know: will those related data loaded every time? Because depending of the current view, some linked table will never be used, and actually they are queried every time. It's a big cost for what it brings to us, no? So how to have this kind of relationship and activate it only when we need it? Some kind of lazy loading which loads the related table only if I need it? 回答1: Cake facilates to

问题 I went through all the possibilities trying to make my project running on Tomcat and point cut the model (getters) and woven them using AspectJ Load Time Weaver. Basically, I followed all the steps in the Spring Documentation http://docs.spring.io/spring/docs/current/spring-framework-reference/html/aop.html#aop-atconfigurable. I also followed the same approach mentioned Lazy/Eager loading/fetching in Neo4j/Spring-Data. My project is divided in two main project: - core: spring-data-neo4j

问题 I'm trying to pull my own flavor of the usual UITableView + async download + cache technique. What I'm doing is, for each cell that gets dequeued in cellForRowAtIndexPath: 1-Check if it's corresponding thumbnail image is already 'cached' in /Library/Caches 2-If it is, just use that. 3-If not, load a default image and enqueue an NSInvocationOperation to take care of it: 4a-The NSInvocationOperation gets the image from a remote server 4b-Does the UIGraphicsBeginContext thing to scale down the

问题 I expect to get only one sql query, but I run into the N+1 select trap. I don't really understand why. Here is is the problem in detail: I have an entity "PlayerRef": @Entity @Table(name = "player_ref") public class PlayerRef { //constructor etc... @OptimisticLock(excluded = true) @LazyCollection(LazyCollectionOption.TRUE) @ManyToMany(fetch = FetchType.LAZY, mappedBy = "playerRefs") public Set<Player> getPlayers() { return players; } } And a class Player: @Entity @Table(name = "player")

问题 I have a data model class Account.In Account class I have one one property Contact(Custom class) and this is having one to one mapping.So I am using like this in Account class: @OneToOne(mappedBy = "account", cascade = CascadeType.ALL, fetch = FetchType.LAZY) public Contact getContact() { return contact; } After doing this contact property is not lazy loading.I have tried optional=false and @LazyToOne (LazyToOneOption.NO_PROXY) .But no luck. Could you please help me? 回答1: Lazy Loading with

问题 I know this exception is caused by some properties being defined as virtual and therefore it's trying to load them lazily after the context has been disposed. However, I don't want to load the entire object graph just to perform a fairly simple query. And if I try to cache the objects when the context is still alive, it tries to lazily load everything, and slows it down considerably . Is there any way of performing the query, and then getting a disconnected result set, so that it doesn't try

问题 I'm a relative newbie at NHibernate, so I'll beg forgiveness in advance if this a stupid question. I've googled it and searched the documentation, and am getting all wrapped around the axle. I'm maintaining/enhancing an existing application that uses NHibernate for a relatively straightforward table. The table has about 10-12 fields, and no foreign key relations. The table contains somewhere around a dozen or so rows, give or take. Two of the fields are huge blobs (multi-megabytes). As a

问题 I'm a relative newbie at NHibernate, so I'll beg forgiveness in advance if this a stupid question. I've googled it and searched the documentation, and am getting all wrapped around the axle. I'm maintaining/enhancing an existing application that uses NHibernate for a relatively straightforward table. The table has about 10-12 fields, and no foreign key relations. The table contains somewhere around a dozen or so rows, give or take. Two of the fields are huge blobs (multi-megabytes). As a