session cache

In hibernate, persistence objects can be divided into three states: transient, persistent, and detached ). Three States of persistent objects can be converted to each other.   This article introduces Hibernate Persistence objects to you. Many

If an object with the same OID (primary key) already exists in the session of hibernate save, an exception occurs. The details are as follows: Exception in thread "Main" org. hibernate. nonuniqueobjectexception: a different object with the same

The SAVE () method of session converts a temporary object to a persistent object. For example:CodeSave a customer object: Customer customer =NewCustomer (); customer. setid (NewLong (9 ));//The OID setting for the temporary customer object is

1. Immediate Search (Enquiry)Immediate retrieval is the call to the Get method, will be issued directly to the database SQL statement query, and the results are placed in the session cache, when the query will be cascaded object pair isolated,

  1) instantaneous status This instance was just created with the new statement and has not been persisted. It is not in the cache of any session, and it has no object identifier (primary key ); Features: It is not associated with any

The first-level cache of Hibernate is provided by the session, so it only exists in the session lifecycle. When the program calls methods such as Save (), update (), saveorupdate, and when the query interface list, filter, or iterate is called, if

Hibernate has two extremely similar methods: Get () and load (). Both of them can read data from the database through the specified object class and ID, and return the corresponding instance. 1. for the get (directly retrieve) method, Hibernate will

When the SELECT statement only selects some attributes of the query persistence class, the query result returned by Hibernate is relational data rather than a persistent object. For example: From customer C inner join C. Orders O group by C. Age

1. In hibernate, the following statement about the primary key generator is wrong (AC). A increment can be used for primary keys of type long, short,or byte (byte type not possible) B identity for databases that support identity columns such as

Internal test pen questions for the use of Hibernate to develop rental systemsFirst, the choice of questions (a total of 25 questions, 2.5 points per question, select one or more, the selection of the wrong choice is not divided)1. In Hibernate, the

Dirty Checkhow did the session end up with a dirty check? When a customer object is added to the session cache,session copies a snapshot of the properties of the value type of the Customer object. When the session cleans up the cache, itThe first

1.HTTPS FoundationHTTPS (Secure hypertext Transfer Protocol) Secure Hypertext Transfer Protocol It is a secure communication channel that is based on HTTP development and is used to exchange information between client computers and servers. It uses

Requirements: Look at such a simple interface. It has a lot of drop-down boxes, and the options in the drop-down boxes are not constant. Because the page is a static HTML page, it cannot be generated dynamically using a background JSP.The previous

Batch processing of 4.2 hibernateHibernate operates the database entirely in an object-oriented manner, and is automatically converted to operations on the database when it is manipulated in an object-oriented manner. For example, by calling the

MySQL Cache Optimization (continued) and mysql Cache Optimization MySQL is cached everywhere. When can I read the MySQL source code and analyze in detail how the cache is used. This part mainly optimizes various explicit cache: Query Cache

This is I recently see shop++4.0 source experience Some of the things, because to do two times development, so first recorded.1. Use the Load () method:hibernate considers that the object (database record) corresponding to the ID must exist in the

Cache LevelWhy use caching?Purpose: Reduce the number of accesses to the database! To improve hibernate execution efficiency!Hibernate Cache Classification:Cache LevelSecond-level cacheConcept1) hibenate cache, also known as the session cache, it

Before learning some new technology, always understand how it is applied, and seldom pay attention to its internal principle. Later found that if a period of time not to know the new technology, almost nothing to remember. But if in-depth to

Beginner easy to get started SSH-hibernate03 three states and cache, This chapter focuses on the three major statuses and caches of hibernate. First, let's look at the three major statuses: For example, the three statuses are temporary, Persistent,

Hibernate is an open source object-relational mapping framework that provides JDBC with a very lightweight object encapsulation, which speaks of pojo mapping with database tables, is a fully automated ORM framework, hibernate can automatically