EclipseLink is an advanced, object- persistence and persistence, supporting the JPA (Java Persistence API) specification and a native API. Refer to the EclipseLink Documentation Center. Please see the EclipseLink Solutions Guide and Understanding EclipseLink ( Concepts Search the EclipseLink JPA documentation wiki.
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Not Used Use for frequently executed non-primary key queries with infrequently changing result sets. For the best performance of selects, where batch fetching is not supported, a join is recommended Lazy loading Without lazy loading on, when EclipseLink retrieves a persistent object, it retrieves all of the dependent objects to which it refers.
Weaving Can disable through persistence. Refreshing can be enabled at the entity level alwaysRefresh or refreshOnlyIfNewer and expiry documentstion at the query level with the eclipselink.
This chapter introduces EclipseLink. This is an optimization feature that lets you tune the way EclipseLink detects changes in an Entity. The persistence property in persistence.
Object-Relational Data Type — For transactional persistence of Java objects to special-purpose structured data source representations optimized for storage in object-relational data type databases such as Oracle Database. You may also consider using optimized loading with LoadGroups which allows a query to force instantiation ecclipselink relationships. Oracle supports the locking policies shown in Table The application constructs message text of type DateFormatwhich is used by the generateHelloMessage method to create events of type HelloWorldEvent.
Where appropriate, this documentation provides links to the pertinent section of the specification. The annotation documentqtion Cacheable specifies whether an entity should be cached.
Can also be set at the query level through query hint ” eclipselink.
EclipseLink Documentation Center | The Eclipse Foundation
This default caching policy can lead to stale data eclopselink the application. Performance Monitoring and Profiling at http: Generally it is recommended that you leave caching enabled. Join fetching is a query optimization feature that enables a single query for a class to return the data to build the instances of that class and its related objects.
Declarative Web Service solution for accessing relational databases. Thanks for the info Doug!
Subsequent queries for these objects access the cache and thus improve performance by reducing data source access and avoiding the cost of rebuilding object’s and their relationships. The schema for the native EclipseLink ddocumentation file http: The student example is intended to provide a simple example of using JPA-RS with a single entity persistence unit in a web application.
Id; Entity public class SaleEvent implements java. The query hints for a query cache are: This provides support for very large L2 caches that span cluster nodes. In the case when you are not concerned about stale data, you should use optimistic locking; this automatically refresh stale objects in the cache on locking errors.
That’s where JPA comes in. If you have an object that is always read from the documentayion, as in a pessimistic locked object, then the cache for that entity should be disabled.
By default, EclipseLink assumes that documentationn application has exclusive access to the data it is using that is, there are no external, non-EclipseLink, applications modifying the data. The EclipseLink properties specify the settings for database read and write operations and logging. For large queries that return a large number of objects, you can configure the row fetch size used in the query to improve performance by reducing the number database hits required to satisfy the selection criteria.
Leave at default AttributeLevel for best performance. For entities that can be updated concurrently, consider using the locking policy to prevent a user from writing over another users changes.
DoNotCheckCache For faster performance on primary key queries, where the data is typically in the cache and does not require a lot of refreshing, it is recommended to check the cache first on these queries using CheckCacheByExactPrimaryKey.