gorm保存方法导致选择查询触发 [英] gorm save method causing a select query to fire

问题描述

我使用grails 1.3.7和zkoss，我的域模型如下，我在会话1中加载Person实体，并通过UI对其进行更改。

在会话2中保存的按下我想保存实体。

因此，从我的作曲家/控制器我调用一个服务方法（事务），然后做人.save（），当我看到被解雇的sql查询时，我看到一个试图检索雇员对象的查询。

之后，保存被触发并抛出一个非唯一对象
异常

org.hibernate.NonUniqueObjectException：具有相同标识符值的另一个对象已经与会话相关：[com.nthdimenzion.domain.Employee＃2]

查询< h>：选择this_.id作为id7_0_，this_.version作为version7_0_，this_.emp_id作为emp4_7_0_，this_.person_id作为person5_7_0_ from person_ro le this_ where this_.class ='com.nthdimenzion.domain.Employee'and this_.emp_id =？
$ b $ class PersonService {
static transactional = true
def savePerson（Person person）{
person = person.save（）;
}

}

  class Person extends Party {
 
 String firstName; 
字符串中间名; 
 static hasMany = [personRoles：PersonRole]  -  lazy loaded 
  

....


$ pre $ class PersonRole {
public static enum ROLETYPES {
EMPLOYEE，AUTHOR
};
public boolean hasRoleType（ROLETYPES roleType）{
return false;

static transients = ['ROLETYPES']
static constraints = {
}
}



class Employee extends PersonRole {
def empRoleType = [ROLETYPES.EMPLOYEE]
String empId
static belongsTo = [person：Person]
static transients = ['empRoleType'，'uid ']
static constraints = {
books（nullable：true）
empId（unique：true）
}
static hasMany = [books：Book]
静态映射= {books cascade：all}
static belongsTo = [person：Person]
......
}


这种行为是否正确？

解决方案

在 Employee 映射中指定 empId 是主键 - 这可能是 NonUniqueObjectException 。

SQL查询必须来自 empId 字段上的唯一约束。

为什么不使用Grails'/ Hibernate隐式 id ，您是否在使用具有特定映射的遗留数据库？

编辑看看为什么独特的约束会导致 NonUniqueObjectException - 请问您可以在没有约束的情况下尝试吗？

如果问题仍然存在，你必须从同一会话中保存两次对象 - 不知道它是如何发生的，也许是由 merge（） - 一个 Employee 。

SQL查询是由唯一性约束引起的，它是正确的。

I am using grails 1.3.7 and zkoss and my domain model is as below, I load the Person entity in session 1 and make changes to it through the UI.

The on press of save in session 2 I want to save the entity.

So from my composer/controller I call a service method(transactional) and then do person.save(), When i see the sql queries being fired I see a query which tries to retrieve the employee object.

After which the save is fired and throws a nonuniqueobjectexception Exception

org.hibernate.NonUniqueObjectException: a different object with the same identifier value was already associated with the session: [com.nthdimenzion.domain.Employee#2]

Query

Hibernate: select this_.id as id7_0_, this_.version as version7_0_, this_.emp_id as emp4_7_0_, this_.person_id as person5_7_0_ from person_role this_ where this_.class='com.nthdimenzion.domain.Employee' and this_.emp_id=?

class PersonService {
static transactional = true
def savePerson(Person person) {
    person = person.save();
}

}

class Person extends Party{

String firstName;
String middleName;  
static hasMany = [ personRoles : PersonRole ] -- lazy loaded

.... }

class PersonRole {
public static enum ROLETYPES{
    EMPLOYEE,AUTHOR
};
public boolean hasRoleType (ROLETYPES roleType){
    return false;
}
static transients = ['ROLETYPES']
static constraints = {
}
 }



class Employee extends PersonRole{
def empRoleType = [ROLETYPES.EMPLOYEE]
String empId
    static belongsTo = [person:Person]
 static transients = ['empRoleType', 'uid']
static constraints = {
    books(nullable:true)
    empId(unique:true)
}
static hasMany = [books:Book]
static mapping = { books cascade:"all" }
static belongsTo = [person:Person]
  ......
}

Is this behavior correct ?

解决方案

You must have specified in Employee mapping that empId is the primary key - that's probably the only reason for NonUniqueObjectException.

The SQL query must come from an unique constraint on empId field.

Why not using Grails'/Hibernate implicit id, are you using a legacy database with a specific mapping?

edit I don't see why would unique constraint cause NonUniqueObjectException - can you please try it without the constraint?

If the problem remains, you must have saved the object twice from the same session - no idea how it can happen, maybe by merge()-ing an Employee from earlier session.

The SQL query is caused by uniqueness constraint and it's the right thing.

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