cascade s customizer

Hibernate often uses set, bag and other sets of 1-to-many relationship, when the entity can be obtained by the relationship between the associated object or object set out, you can also set Cacade for association update and delete. This has to say that Hibernate's ORM is doing very well, very close to Oo's usage habits.But the database access still must consider the performance problem, after setting 1 to many this kind of relationship, the query will

Hibernate n+1 Problems and SolutionsWhy the problem occurred:Hibernate often uses set, bag and other sets of 1-to-many relationship, when the entity can be obtained by the relationship between the associated object or object set out, you can also set Cacade for association update and delete. This has to say that Hibernate's ORM is doing very well, very close to Oo's usage habits.But the database access still must consider the performance problem, afte

up cache, each cleanup cache call Session.flush () method will emit 20 insert statements, but there is no data in the database and so all the data issued INSERT statement Unified COMMIT TRANSACTION, A transaction is a hierarchy with a session and therefore requires a unified control transaction.Hibernate n+1 ProblemsHibernate often uses set and other sets to represent 1-to-many relationships, and in the Iron Academy project We do, we can retrieve the associated object or collection of objects a

the cache. PS: After saving, run get or load to know the Object ID. After the save method is executed, although there is no data in the database, the Object ID has been generated and can be queried through this ID. Batch insert data When you insert data in batches, insert a part of data each time. For example, insert 20 data records at a time without one insert. public void testInserBatch() {Session session = sf.openSession();session.beginTransaction();for(int i=0; i Cache is cleared every ti

columns in the view are determined by it, otherwise the columns included in the query's results are determined. (2) Deletion of views The view deletion statement provided by the SQL language is Drop view, which is used in the following format: DROP View [cacade| RESTRICT] The most important difference between the deletion of a view and the deletion of the general relational table is that the deletion of the view simply deletes the view's organi