Hibernate懒加载深入分析(国外英文资料).doc

Hibernate懒加载深入分析(国外英文资料) Can lazy loading improve performance? Can not simply say can, because of the Hibernate mapping to drag down the SQL performance, so come up with a lazy loading to make up for. Just make up for, will not go beyond. So you dont use lazy loading overall performance is improved, but the overall performance is not falling, it luckily. -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- Hibernates lazy properties can be configured: (common) set list , you can evaluate true, false, extra Defaults to true, when to true, will be lazy loading, when accessing a collection property to a SQL statement. But the set. The size (), is not very smart, will not generate the count () statement, but all records assigned to set it up. The select count (*) from tableName is generated when the call to the set is called set.size () (less) many-to-one one--to-one , you can use false, proxy, noproxy When is true, there will be a lazy loading features, N + 1 problem when to false, such as corresponding to a class, a student with a SQL found 10 students, when visiting student of the class attribute Hibernate will produce 10 SQL respectively detected each student of the corresponding class. On the class label, you can evaluate true, false By default to true, when it is false, the load () method will lose the lazy loading feature as well as get (), which does not affect the lazy feature on the set ( set list ) (no) property tag, you can evaluate true, false The default value is false, lazy load a field, meaningless, not used -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- The difference between get () and load () The get () lazy load feature executes the SQL query immediately. Load () has a lazy loading features, wi