hashcode composite

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composite primary key hibernate mapping of an example

MealfeeDetail.hbm.xml MealfeeDetail.java Database table fields:

hibernate3 annotations to generate an embedded composite primary key or primary key of the method and examples of

The continuous development of Hibernate, Java database persistence almost become a de facto standard, because it is very powerful, flexible, and possess excellent performance. Traditionally, Hibernate configuration depend on external XML file: database ma

hibernate composite-id

Encounter the following problems: In the browser display getSession (). Save (...) sentence has been reported nullException. First of all, the problem is definitely not getSession reference to the use of the Internet are so used, getSession () and th ...

Hibernate composite primary key

When a table has multiple fields in a composite primary key, hibernate how to handle it? As follows: Configuration is as follows: POJO as follows: We combined the two primary key fields in a POJO in the extracted. And as a component of another POJO. ...

hibernate configuration and use of composite primary key

When using the hibernate sometimes encounter configuration and use of composite primary key, such as the following table is to use a composite primary key So when in the configuration file to use hibernate composite-id to identify a compound primary key p

The composite primary key Hibernate

First, the database is as follows (MS-SQL2005): - Create a person table - Delete Person table DROP TABLE person; - Create Person Form CREATE TABLE person ( name VARCHAR (100) not null, phone VARCHAR (50) not null, age INT, PRIMARY KEY (name, phone) )

Hibernate fine-grained classification and composite primary keys

Fine-grained division Person.hbm.xml profile <? Xml version = "1.0" encoding = 'UTF-8'?> <! DOCTYPE hibernate-mapping PUBLIC "- / / Hibernate / Hibernate Mapping DTD 3.0 / / EN" "Http://hibernate.sourceforge.

hibernate (jpa) composite primary key annotation statement Ways

In the design of the database tables are designed with a composite primary key of the table, that table's record by more than one field joint identification, such as: Table CREATE TABLE TB_HOUR_DATA ( STAT_DATE DATE NOT NULL, PATH_ID NUMBER(20) NOT NULL,

HashMap override hashCode and equals methods

Original Address: http://blog.chinaunix.net/u1/53616/showart_432480.html We can put the definition of the basic variables or objects to carry out its own key -> value lookup Let's create a class of its own, as a hashmap of key Note that I have ...

JAVA_ advanced features (hashCode, clone, comparator, Class reflection, serialization)

http://blog.csdn.net/wjp553650958/archive/2009/09/28/4601103.aspx JAVA_ advanced features (hashCode, clone, comparator, Class reflection, serialization) <script type="text/javascript"> </ script> <script type="text/javascript

hashcode, equals

Put in to the HashSet collection of data, because of the underlying HashSet is HashMap stored in the Key property, so can not be repeated, that if he He judged the elements do not repeat it. This time, he concluded that there are two steps. 1. Call h ...

equals () & hashcode () Container Collection

Two objects, each equals (), two objects must have the same hashCode! true-true-true 96354 9635496354 Common Map interface class: HashMap, TreeMap, HashTable. HashMap object inside the store did not order, TreeMap objects inside the store with the or ...

Design patterns seen by the (combined mode Composite)

Definition: Object to a tree structure to organize themselves in order to reach "section - as a whole," the hierarchical structure, allowing the client portfolio of individual objects and the use of an object consistent. Combined mode in fa ...

equals & hashcode

import java.util .*; class A ( private int i; public A (int i) ( this.i = i; ) public String toString () ( return "" + i; ) public boolean equals (Object o) ( A a = (A) o; return (ai == i)? true: false; ) public int hashCode () ( return i; ...

equals, == and hashcode

equals and == hashcode == When acting on two objects when an object reference comparison (reference) is pointing to the same object String override the parent class Object's equals method returns true with the same content Running Results: false ...

The role of hashcode

Original Source: http://blog.chenlb.com/2009/09/hashcode-effect.html Java object Hashcode What is the role? Can be associated with the data structure hash table (hash table), hash function. Object.hashCode () is a hash function, used to calculate the ...

Hibernate composite primary key of the simple application of

1, written by someone else examples of Web site address: http://www.blogjava.net/alex/archive/2006/11/09/80231.html 2, you can also see the video Xinghua teachers also have to explain, pay attention to areas shown in Figure instructions. Click the pi ...

JSF2 of the template and composite components

Templates and composite components are Java ™ Server Faces (JSF) 2 of two powerful features, with the help of these two features, you can achieve easily modified and extended user interface. JSF2 by default the current display technology - Facelets - ...

Why, after rewriting the object equals the best method of rewriting the object's hashcode

To determine whether two objects are generally equal to the equals method with an object, but seldom use the object ==. If you change the equals method, that is changed according to object-based storage address compare methods. Then if there is no re ...

Oracle SOA Suite: Creating Composite Services with BPEL

Despite the fact that BPEL is mainly responsible for preparing to write long-running process, it also provides an excellent way to create composite services, namely, a collection of other services. We give a simple example: I have a stock quote for a ...

hiberante composite primary key + oscache cache can not hit the problem

Recently a project to do stress testing it was discovered that the memory rising from the feeling of memory leaks observed jconsole issue. Installation jprofiler, to track the changes in memory objects found oscache constantly adding objects, estimat ...

JAVA in the equals () and hashCode () method

Quote In the Java language, equals () and hashCode () using the two functions are closely co-ordinated if you are one of their own design, we must design another one. In most cases, these two functions are not considered, the direct use of their defa ...

HashMap Analysis of the settlement of the conflict-HashCode

Overview: Through a certain algorithm, the key's hashcode converted into an array index; will be key, value, hash and other information stored in an array of the corresponding index position. Question: 1. Some key the same as the hashcode 2.hashc ...

java in the hashcode () and equals () of the Xiang Jie [change]

java in the hashcode () and equals () of the Xiang Jie [change] October 30, 2008 Thursday, 11:23 PM Research this afternoon for a long time hashcode () and equals () method, finally had a little bit to understand, write down and share 1. First of equals (

Hibernate many to many mapping real-column (composite primary key)

Note: set the order of the key attributes of the order with the same entity class! ! ! !

java in equals and hashCode (Reprinted)

At some point, we need to determine whether two objects are equal. Java, every class inherits from Object class. It uses the equals () and hashCode () method to determine these two Object for equality. 1. Equals () Need to meet the 5 points: A self-e ...

equals () and hashCode () detailed analysis (reproduced)

HashCode is generated after the address and hash algorithm index values 1. First equals () and hashcode () These two methods are inherited from object class in the. equals () method in the object class is defined as follows: is clearly the address of ...

Nylon Composite Micro Fiber Alkali Splitting Process

Keywords: finishing, splitting technology, micro fiber, composite fiber, polyethylene terephthalate fiber, polyamide fiber Han Yan, Gao Ming, Xiang-Ying Meng, Li Yong, Zhu Ping (Institute of Chemical Technology, Qingdao University, Qingdao 266071) O ...

Composite scouring enzyme 301L in the Ma / sticky pre-treatment

Keywords: pre-treatment, enzymes, blended fabric, linen, viscose LIU Jiang-bo, Han Li, Chun-Guang Li, Lo Wei-hsin (Huafang Share Technology Center, Shandong Binzhou 256617) O Introduction traditional scouring and bleaching process using caustic soda ...

(Transfer) Mysql limit optimization, from one million to 10 million pages quickly - a reference to a composite index and applied to lightweight framework

http://hi.baidu.com/% D4% E7% B9% C8% C9% E7% C7% F8/blog/item/1fd6f3d04927fd86a1ec9c44.html MySql performance in the end to how high? Php spent more than six months, the real depth to think about this issue or from the day before yesterday. Had had a pai

String hashcode algorithm class

Engage in a night of equals () method and the hashCode () and == the relationship between the Well or can not override the equals () comparison object is to return true, is that the two objects are equal (that reference the same object) the hashcode ...

PET / PA composite ultra-fine silk fabric dyeing Difficulties and Countermeasures

Keywords: dyeing, dyeing properties, micro fiber, polyethylene terephthalate fiber, polyamide fiber Analysis: Cui Haoran Dyeing Co., Ltd. Changzhou New Hao 1 Introduction Nylon Composite ultrafine silk, is in a single wire in a certain regular arrang ...

Composite index of regulation

1, composite index of the rules take effect Query must contain the combination of the index in one or more conditions to take effect, and the first column is a must. For example: create index idx1 on SM_USER (USER_CODE, NAME, ORG_ID) Following query ...

Corduroy pad dyeing of polyester and nylon composite wire

Keywords: polyester and nylon composite wire cord, pad dyeing Abstract: According to the characteristics of polyester and nylon composite wire corduroy, the conventional process for the high temperature high pressure dyeing, dyeing machine dyeing, dyeing

Silk / wool composite wire fabric how to use acid dyes to dye the same color

Keywords: silk / wool composite wire fabric, weak acid dyes silk and wool fibers of different physical and chemical structure, dyeing properties of the weak acid dyes have a greater difference. Slower initial uptake rate of wool, while the equilibrium dye

DTY pad dyeing polyester and nylon composite wire

Keywords: polyester and nylon Filament DTY DTY pad dyeing polyester and nylon composite wire is the island superfine fiber, its large surface area, adsorption dye fast, slow diffusion, dyeing, poor microfiber reflection coefficient, to dye have the s ...

Nano Science and Technology (Nano-ST) and polymer based composite materials Introduction

Keyword: Nano Science and Technology (Nano-ST) and polymer-based nanomaterials Introduction Qiong Li Shouping (Polymer Science and Engineering, Qingdao Institute of Chemical Technology 266042) information, energy, new materials are considered the three pi

Medical protective clothing and finishing composite technology

Keyword: Frank Jian Wu Yuqin Wang Haibin Lvliang Tao (Qingdao Jifa Group Co., Ltd.) I. Introduction of protective clothing is a particular occasion the human body has a defense invasion of harmful substances, reasonable and effective micro-environmen ...

equals the true time, hashcode must be equal

equals the true time, hashcode must be equal, this rule was not previously noted, each override equals methods are not considered hahsCode, write here to make a mark. If you override equals, but not modify the hashCode, HashMap, and the like in the u ...

hbernate composite primary key cascade configuration

1. mapping Two tables used here were TBL_OSU_PRODUCTFILTERDETAIL_I and TBL_OSU_PRODUCTFILTER_I, the former compound primary key, the latter with the former-to-many relationship. 1.TBL_OSU_PRODUCTFILTERDETAIL_I <? Xml version = "1.0" encoding

The use of the advantages of solid wood composite door

Wooden decoration of choice for the family, it seems style and good taste, can improve the overall charm of home. The doors will the consumers know about? In addition to the basic maintenance of wooden doors and windows, how many people can say solid ...

Java base 2: hashCode brief description of the role, may lead to objects in the collection can not be removed

import java.util.ArrayList; import java.util.Collection; import java.util.HashSet; /** * hashCode The role of * * @author Zhang Xue * */ public class HashCodeStudy { @SuppressWarnings("unchecked") public static void main(String[] args) { Point p1 = new Po

The performance of steel framed composite pipe

Steel skeleton improved composite pipe is a new type of steel framed polyethylene plastic pipe. This pipe is also known as srtp tube. The new pipeline is to use high-strength steel wire through the frame and thermoplastic polyethylene as raw material ...

JAVA based (a) equals and == and hashCode

JAVA based (a) equals and == and hashCode According to excerpts online content Heap (heap) and stack (stack) the difference between heap memory: heapstorage heap storage allocation: heapstorage allocation heap storage management: heap storage managem

Java, covering the convention and simple method hashCode

Object in general agreement on the hasdCode: 1. During the execution of the application, as long as the object of the equals method of comparison operation by the use of the information has not been modified, then this call many times the same object

Installation of steel framed composite pipe connection

Thermoplastic piping system design water supply pressure, generally refers to transmission medium temperature is 20 ℃, the bearing capacity of plastic pipe. Select cold water pipes, generally this value as selection criteria, but as is the transmissi

Metal composite material applications

Composite material is a mixture. In many areas played a significant role, replacing many traditional materials. Composite materials into their component metals and metal composites, metal and metal composite materials, non-metallic and non metallic c

Commonplace - hashCode () and equals ()

The default behavior defined in java.lang.Object in native int hashCode (); Native methods of preparing an example: Java Tip 23: Write Native methods JDK JVM implementation is the object of the address as the hashCode boolean equals (Object obj); Def

Analysis of Java objects use equals and hashCode

In the Java language, equals () and hashCode () using the two functions are closely matching, if you had one of their own design, we must design another. In most cases, these two functions are not taken into account, directly to their default design

java in the hashcode () methods and equals method [change]

hashcode这个方法是用来鉴定2个对象是否相等的。 那你会说,不是还有equals这个方法吗? 不错,这2个方法都是用来判断2个对象是否相等的。但是他们是有区别的。 一般来讲,equals这个方法是给用户调用的,如果你想判断2个对象是否相等,你可以重写equals方法,然后在代码中 调用,就可以判断他们是否相等了。简单来讲,equals方法主要是用来判断从表面上看或者从内容上看,2个对象是不是 相等。举个例子,有个学生类,属性只有姓名和性别,那么我们可以认为只要姓名和性别相等,那么就说这2个
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