Hibernate delayed Loading

First, it indicates that the delayed loading of Hibernate3 is only useful for load, get, and find internal value methods, and does not work for SQL writing such as hql. The delayed loading mechanism is proposed to avoid unnecessary performance overhead. The so-called delayed loading means that data loading is performed only when data is actually needed. Hibernate provides delayed loading of object objects and delayed loading of collections, and delayed loading of attributes in Hibernate3. Next we will introduce the details of these types of delayed loading. A. Delayed loading of object:To use delayed loading for object objects, you must configure the ing configuration file of the object as follows: B. Delayed loading of Collection types:In the delayed Loading Mechanism of hibernate, it is of the most significant significance for the application of the set type, because it may greatly improve the performance, so hibernate has made a lot of efforts, this includes the independent implementation of JDK collection. In one-to-Multiple Association, the Set set defined to hold the associated object is not Java. util. set type or its subtype, but net. SF. hibernate. collection. set type. hibernate implements delayed loading of set types by using custom collection classes. To use delayed loading for the collection type, we must configure the related section of our object class as follows: C. Delayed attribute loading:In Hibernate3, a new feature-delayed loading of attributes is introduced, which provides a powerful tool for obtaining high-performance queries. As mentioned above, when reading a big data object, there is a resume field in the User object, which is a java. SQL. the Clob type contains the user's resume information. When we load this object, we have to load this field every time, whether or not we really need it, in addition, reading such big data objects will bring about great performance overhead. In Hibernate2, we only break down the User class through the granularity subdivision of the surface performance we mentioned earlier (refer to the discussion in that section ), however, in Hibernate3, we can use the property delay loading mechanism to obtain the ability to read data from this field only when we really need to operate on this field, therefore, we must configure our object class as follows: