Mybatis level 1 and level 2 cache, and mybatis Level 2 CacheLevel 1 Cache
First, perform a test to create a mapper configuration file and mapper interface. Here I use the simplest query for demonstration.
public interface UserMapper { List
Then write a unit test
Public c
Hibernate Level 1 cache and level 2 cache, hibernate Level 1 Cache
The cache is between applications and physical data sources. It is used to reduce the frequency of applications accessing physical data sources and improve the running performance of applications. Data in the cache is the replication of data in the phys
Level 1 cache, level 2 cache, and lazy loading (transfer) in Hibernate, and level 1 cache in hibernate1. Why cache?
Hibernate uses cache to reduce the number of accesses to the database, thus improving the execution efficiency of hibernate. There are two types of cache in hibernate:
Hibernate
Secondary cache:
Definition:
1. The second-level cache is called the process-level cache or sessionFactory-level cache. The second-level cache can be shared by all sessions.
2. the life cycle of the second-level cache i
Hibernate cache category:Session cache, level 1 cache;
Sessionfactory caches are divided into built-in caches and external caches. the built-in cache stores data contained in some collection attributes of the sessionfactory object (ing element data and predefined SQL statements). For applications, it is read-only. the external cache stores copies of database data, which is similar to the primary cache. in addition to using memory as the storage medium
This article describes how to use jQuery's AJAX function and asp.net to achieve the three-level linkage effect between provinces and municipalities. Other second-level, third-level, or multi-level linkages can also be completed according to this method.
The data table involved in this article is City, for convenient m
Before giving you a detailed description of the second-level cache of hibernate, we will first let you know the next-level cache, and then give a comprehensive introduction to the second-level cache of hibernate. Hibernate provides two levels of cache. The first level of cache is session-
(Rational)
Summary
The Software Engineering Association (SEI) Capability Maturity Model (CMM) provides a well-known software process maturity benchmark. CMM has become a popular tool in many fields to evaluate the maturity of an organization's software processes. This White Paper explains how rational uniied process supports organizations that are working to reach CMM Level 2 (repeatable) and
get operations will not cause nhib.pdf to query the database, but retrieve objects from the first-level cache.
Clear Cache
We use the following statement to request the session to remove an entity from the first-level cache:
Session. evict (product );
To completely clear the cache, you can use the following code:
Session. Clear ();
The preceding statement should only be used in special cases, be
Mybatis (9) ------ Level 1 cache, level 2 cache, mybatis ------
In the previous chapter, we explained how to improve query efficiency through mybatis lazy loading. In addition to lazy loading, what other methods can be used to improve query efficiency? This is the cache in this chapter.
Mybatis provides a level-1 cache
Hibernate uses cache (level 1, level 2, and query) to improve system performance and hibernate system performanceIn hibernate, we usually use three types of caches: level-1 cache, level-2 cache, and query cache. Below we will anal
I,Level 1 Cache1. The first-level cache only caches the entire object and does not cache object attributes;2. The first-level cache is a session-level cache and cannot be used across multiple session objects;3. The load/get method of the session supports reading and writing
Hibernate provides two levels of cache. The first level of cache is session-level cache, which belongs to the scope of transactions. This level of cache is managed by Hibernate and generally requires no intervention. The second level of cache is the sessionfactory level cach
Before introducing the cache mechanism of hibernate, let's take a look at what cache is:Cache: a very common concept in the computer field. The cache is a collection. It is between an application and a permanent data storage source (such as a file or database on a hard disk). Its function is to reduce the frequency of applications directly reading and writing permanent data storage sources, this improves the Running Performance of applications. The cached data is the copy of the data in the data
Transaction scope: The cache can only be accessed by the current transaction. The life cycle of the cache depends on the lifecycle of the transaction, and when the transaction ends, the cache ends the lifecycle. In this range, the cached media is memory. Note: The first-level cache, which is the session cache, is actually a transaction-scoped cache.
2 Process scope: caching is shared by all transactions w
[Hibernate] level-1 and level-2 buffering, and hibernate Buffering
Hibernate buffer is divided into two types by level: Session and SessionFactory. Some are also three types, and the other is Query Buffer. Of course, query buffering relies on second-level buffering.
OK. Wha
Level 1 and level 2 pointers in C Language
Pointer Concept
The pointer is the address, which can be used to find the specified data.
The pointer is the address, so when using it, it is often said that the pointer variable is a pointer
The pointer variable is the variable that stores the address.
Int * p1; // a variable is applied for, that is, a memory is opened
principle of caching is that when the CPU needs to read a piece of data, it first looks for it from the cache. if it finds it, it immediately reads it and sends it to the CPU for processing. If it does not, it reads data from the memory at a relatively slow speed and sends it to the CPU for processing. At the same time, it transfers the data block of the data to the cache, this allows you to read the entire block of data from the cache without calling the memory.
This reading mechanism makes t
Level 1 cache and level 2 Cache
A. level 1 cache (Session-level cache): load the same object twice in a session. During load, Hibernate first searches for the object in the session cache, load data to the database if not found. Therefore, when an object is loaded twice in th
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