Develop Reference

Hibernate lazy loading not working many-to-one XML

I'm trying to lazily load a collection in Hibernate. From what I've read this is the best practice way to do this:
Session session = HibernateUtil.getSessionFactory().openSession();
session.beginTransaction();
Hibernate.initialize(this.truckReviews);
session.getTransaction().commit();
session.close();
return this.truckReview;
However, when I run this unit test, the assertion fails:
Truck realTruck = Truck.getTruckByID(1);
TruckReview realFakeReview = new TruckReview();
realFakeReview.setTruck(realTruck);
realFakeReview.setUser(IntegrationTestResources.getTestUser());
realFakeReview.setReviewDate(new Date());
realFakeReview.setReviewStars(5);
realFakeReview.setReviewText("fake review");
realFakeReview.save();
assertTrue(realTruck.loadReviews().contains(realFakeReview));
realFakeReview.delete();
Needless to say, I'm a bit confused since other StackOverflow threads say this is the way to do it properly. I feel like I must be missing something very obvious but I'm still new to Hibernate and have no idea what.
Here's the mapping file for this class:
<hibernate-mapping>
<class name="edu.temple.tutrucks.Truck" table="truck" catalog="TUTrucks" optimistic-lock="version">
<id name="id" type="int">
<column name="id" />
<generator class="identity" />
</id>
<property name="truckName" type="string">
<column name="truck_name" not-null="true" />
</property>
<property name="latitude" type="double">
<column name="latitude" precision="22" scale="0" not-null="true" />
</property>
<property name="longitude" type="double">
<column name="longitude" precision="22" scale="0" not-null="true" />
</property>
<property name="openingTime" type="imm_time">
<column name="opening_time" not-null="false"></column>
</property>
<property name="closingTime" type="imm_time">
<column name="closing_time" not-null="false"></column>
</property>
<property name="avatar" type="string">
<column name="avatar"></column>
</property>
<list name="truckReviews" table="truck_review" inverse="true" lazy="true" fetch="select">
<key>
<column name="truck_id" />
</key>
<list-index column="review_stars" />
<one-to-many class="edu.temple.tutrucks.TruckReview" />
</list>
<list name="menus" table="menu" inverse="true" lazy="false" fetch="select">
<key>
<column name="truck_id" />
</key>
<list-index column="id" />
<one-to-many class="edu.temple.tutrucks.Menu" />
</list>
<set name="tags" table="tag_truck_map" inverse="true" lazy="true" fetch="select">
<key>
<column name="truck_id" />
</key>
<many-to-many column="tag_id" class="edu.temple.tutrucks.Tag"></many-to-many>
</set>
</class>
</hibernate-mapping>
Thanks in advance.
UPDATE: Still having issues, I've changed the loadReviews method to this
#Override
public Truck loadReviews() { // lazy loading needs to be fixed
Session session = HibernateUtil.getSessionFactory().openSession();
session.beginTransaction();
Truck retval = (Truck) session.get(Truck.class, this.getId());
Hibernate.initialize(retail.getTruckReviews());
session.getTransaction().commit();
session.close();
retval.truckReviews.size();
return retval;
}
And the test now looks like this
#Test
public void testloadReviews() {
Truck realTruck = Truck.getTruckByID(1, false, false);
TruckReview realFakeReview = new TruckReview();
realFakeReview.setTruck(realTruck);
realFakeReview.setUser(IntegrationTestResources.getTestUser());
realFakeReview.setReviewDate(new Date());
realFakeReview.setReviewStars(5);
realFakeReview.setReviewText("fake review");
realFakeReview.save();
assertTrue(realTruck.loadReviews().getTruckReviews().contains(realFakeReview));
realFakeReview.delete();
}

The problem is that you can't to use realTruck form one session to do Hibernate.initialize(this.truckReviews) using other session
Session session = HibernateUtil.getSessionFactory().openSession();
session.beginTransaction();
// you need to reload persistent with
// realTruck = session.get(), realTruck = session.load() here
Hibernate.initialize(this.getTruckReviews());
You need to use a getter not a property, because of Hibernate need to have a proxy. A proxy is returned by a getter
Hibernate.initialize(this.getTruckReviews());

How to get only parent without children in Hibernate and without lazy exception?

How to get only parent without children in Hibernate and without lazy exception, when you trying to access chidlren filed after closing session?
I mean, a kind of pure parent obtainingm but I beed to be sure, that somebody will not obtain them with getter or will not catch a lazy exception.
<class name="com.electronic.commerce.models.Category" table="Category">
<id name="id" type="long" access="property">
<column name="categoryId" length="20"/>
<generator class="native"/>
</id>
<property name="name" column="categoryName" type="string"/>
<property name="parentId" column="categoryParentId" type="long"/>
<bag name="children" table="Category" inverse="true" lazy="true" fetch="select">
<key>
<column name="categoryParentId" not-null="true"/>
</key>
<one-to-many class="com.electronic.commerce.models.Category"/>
</bag>
</class>

Mixed solution
Xml:
<prop key="hibernate.enable_lazy_load_no_trans">false</prop>
Java:
DefaultTransactionDefinition defaultTransactionDefinition = new DefaultTransactionDefinition();
defaultTransactionDefinition.setPropagationBehavior(transactionDefinition);
transactionManager.getTransaction(defaultTransactionDefinition);

Hibernate org.hibernate.MappingException... an associon ..to unmapped class- Many toMany

I have auto generated the code using netbeans to create a Hibernate configuration; so I have two tables mapped like this (Many-to-Many) :
<hibernate-mapping auto-import="true">
<class name="com.antoiovi.jobprograms.entity.Roles" table="roles" catalog="jobprograms">
<id name="rolesName" type="string">
<column name="roles_name" length="20" />
<generator class="assigned" />
</id>
<set name="userses" table="users_roles" inverse="true" lazy="false" fetch="select" cascade="all">
<key>
<column name="role_name" length="20" not-null="true" />
</key>
<many-to-many entity-name="com.antoiovi.jobprograms.entity.Users">
<column name="user_name" length="15" not-null="true" />
</many-to-many>
</set>
</class>
<hibernate-mapping auto-import="true">
<class name="com.antoiovi.jobprograms.entity.Users" table="users" catalog="jobprograms">
<id name="idusers" type="java.lang.Integer">
<column name="idusers" />
<generator class="identity" />
</id>
<property name="userName" type="string">
<column name="user_name" length="15" not-null="true" unique="true" />
</property>
<property name="userPass" type="string">
<column name="user_pass" length="15" not-null="true" />
</property>
<property name="firstName" type="string">
<column name="first_name" length="20" />
</property>
<property name="lastName" type="string">
<column name="last_name" length="25" />
</property>
<set name="roleses" table="users_roles" inverse="true" lazy="false" fetch="select" cascade="all">
<key>
<column name="user_name" length="15" not-null="true" />
</key>
<many-to-many entity-name="com.antoiovi.jobprograms.entity.Roles">
<column name="role_name" length="20" not-null="true" />
</many-to-many>
</set>
<set name="jobprograms" table="jobprogram" inverse="true" lazy="false" fetch="select" cascade="all">
<key>
<column name="users_idusers" not-null="true" />
</key>
<one-to-many class="com.antoiovi.jobprograms.entity.Jobprogram" />
</set>
</class>
I have made some modification as you can see above (auto-import=true, lazy=false), cause i have the error message
rg.hibernate.MappingException: An association from the table users_roles refers to an unmapped class: com.antoiovi.jobprograms.entity.Roles
at org.hibernate.cfg.Configuration.secondPassCompileForeignKeys(Configuration.java:1824)
at org.hibernate.cfg.Configuration.originalSecondPassCompile(Configuration.java:1756)
at org.hibernate.cfg.Configuration.secondPassCompile(Configuration.java:1423)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1856)
The config file is
<hibernate-configuration>
org.hibernate.dialect.MySQLDialect
com.mysql.jdbc.Driver
jdbc:mysql://localhost:3306/jobprograms?zeroDateTimeBehavior=convertToNull
jobprograms_ad
xxxxx
thread
true
org.hibernate.hql.classic.ClassicQueryTranslatorFactory
true
the classes have refernce like this :
'#ManyToMany(fetch=FetchType.LAZY, mappedBy="roleses")
public Set<Users> getUserses() {
return this.userses;
} '
#ManyToMany(fetch=FetchType.EAGER)
#JoinTable(name="users_roles", catalog="jobprograms", joinColumns = {
#JoinColumn(name="user_name", nullable=false, updatable=false) }, inverseJoinColumns = {
#JoinColumn(name="role_name", nullable=false, updatable=false) })
public Set<Roles> getRoleses() {
return this.roleses;
}
wHEN RUNNING I HAVE THE ERROR org.hibernate.exception.SQLGrammarException, and in fact the entiti is loaded, but the set<> not..,
When testing the error is
org.hibernate.MappingException: An association from the table users_roles refers to an unmapped class: com.antoiovi.jobprograms.entity.Roles, and the HSQL ar not executed.
I tried to look in others post but i couldn't find an answer. Can anybody help me?
In config file the entities are all declared;
I think yhe promlem is in the mapping :
e <set name="roleses" table="users_roles" inverse="false" lazy="true" fetch="select" >
<key >
<column name="user_name" length="15" not-null="true" />
</key>
<many-to-many entity-name="test.Roles" property-ref="rolesName">
<column name="role_name" length="20" not-null="true" />
</many-to-many>
</set>
<set name="jobprograms" table="jobprogram" inverse="true" lazy="true" fetch="select">
<key>
<column name="users_idusers" not-null="true" />
</key>
<one-to-many class="test.Jobprogram" />
</set>
and
enter <class name="test.Roles" table="roles" catalog="jobprograms">
<id name="rolesName" type="string">
<column name="roles_name" length="20" />
<generator class="assigned" />
</id>
<set name="userses" table="users_roles" inverse="true" lazy="true" fetch="select">
<key property-ref="rolesName">
<column name="role_name" length="20" not-null="true" />
</key>
<many-to-many entity-name="test.Users" property-ref="userName">
<column name="user_name" length="15" not-null="true" />
</many-to-many>
</set>
</class>
....

this error
org.hibernate.MappingException: An association from the table users_roles refers to an unmapped class: com.antoiovi.jobprograms.entity.Roles
comes when hibernate configuration dont know about entity(Roles) mapping , either you have missed introducing enitity Roles to the hibernate configuration or you have not used correct name , please check configuraiton file and included com.antoiovi.jobprograms.entity.Roles as resourse

I think to have resolved the problem. Actually the proble are unmapped entities. But this happens because the database is not 'well formed'. Indeed the database ha 3 table users, users_roles, roles; the table roles has only one column as primarykey (varchar),and the table user_roles refers to it from its column user_roles; when forword enginering the ide (in the case netbeans) creates only 2 entities: 'Users', and 'Roles'; So i have re-designed the schema putting some virtual primary key, and creating unique constaint instead. Now i have 3 entities : Users,UserRoles, and Roles.

org.hibernate.exception.MappingException or ConstraintViolation

I am using hibernate 4.1.9. I have Users, and the Users have a list of Accounts, and Accounts have list of Transactions. Here is my hbm.xml
<?xml version="1.0"?>
<class name="User" table="users">
<id name="userId" column="userid">
<generator class="increment"/>
</id>
<property name="username" column="username" not-null="true"/>
<property name="password" column="password" not-null="true"/>
<property name="registerDate" type="timestamp" column="register_date"/>
<list name="accounts" table="accounts" inverse="true" cascade="all">
<key column="userid" not-null="true"/>
<index column="accountid"/>
<one-to-many class="com.joe.data.Account"/>
</list>
</class>
<class name="Account" table="accounts">
<id name="accountId" column="accountid">
<generator class="increment"/>
</id>
<property name="balance" type="big_decimal" column="balance"/>
<property name="lastModified" type="timestamp" column="last_modified"/>
<list name="txns" table="transactions" inverse="true" cascade="all">
<key column="accountId" not-null="true"/>
<index column="transactionId"/>
<one-to-many class="com.joe.data.Transaction"/>
</list>
<many-to-one name="userId" class="User" column="userid" not-null="true"
unique="true" cascade="all"/>
<many-to-one name="accountType" class="AccountType" column="account_type"
not-null="true" cascade="all" unique="true" />
</class>
<class name="Transaction" table="transactions">
<id name="transactionId" column="transactionid">
<generator class="increment"/>
</id>
<property name="description" column="description"/>
<property name="amount" type="big_decimal" column="amount"/>
<property name="dateAdded" column="date_added"/>
<property name="reoccuring" type="numeric_boolean" column="reoccuring"/>
<many-to-one name="category" class="Category" column="category"
not-null="true" cascade="all" unique="true" />
</class>
<class name="Category" table="categories">
<id name="categoryId" column="categoryid"/>
<property name="categoryName" column="categoryname" not-null="true"/>
</class>
<class name="AccountType" table="account_types">
<id name="accountType" column="account_type"/>
<property name="accountName" column="name"/>
</class>
If I leave inverse="true" on the list of accounts (in the User) I get the ConstraintViolationException because the userid is not getting put in the insert query. If I take inverse="true" off of the list of accounts, I get org.hibernate.MappingException: Repeated column in mapping for entity: com.joe.data.Account column: accountid (should be mapped with insert="false" update="false")
To clarify lowercase names are database columns names, camel case are class variable names. I know Transaction class isn't working quite right yet, but if I could get the Accounts to insert I could do the same thing to get the Transactions to insert.
Edit: I added the many-to-one on the Account class and now I am getting another exception where hibernate is complaining about missing a getter for userId in com.joe.data.Account

In order to get inverse="true" work, you need to define many-to-one for User in Account and for Account in Transaction class and mappings.

Hibernate parent/child relationship. Why is object saved twice?

I am looking into Hibernate's parent/child relationships.
I have 3 entities Employee Customers and Orders.
Their relationship is
Employee 1 <-> N Orders
Customer 1 <-> N Orders
I want to be able to save/update/delete Customer objects and Employees and Orders but I want to use some interface so that the calling code does not deal with any Hibernate or JPA stuff.
E.g. I tried something like the following:
class Utils{
public static void saveObject(Object o){
logger.debug(o.toString());
Session session = getSessionFactory().openSession();
Transaction tx = session.beginTransaction();
session.save(o);
tx.commit();
session.close();
}
}
and in the calling code I do:
Employee employee = new Employee();
//set data on employee
Customer customer = new Customer();
//set data on customer
Order order = new Order();
//set data on order
employee.addOrder(order);//this adds order to its list, order gets a reference of employee as parent
customer.addOrder(order);//this adds order to its list, order gets a reference of customer as parent
Utils.saveObject(customer);
Utils.saveObject(employee);
Now I noticed that with this code, 2 records of employee are created instead of 1.
If I only do:
Utils.saveObject(customer);
Only 1 (correctly) record is created.
Why does this happen?
Does this happens because the same Order object is saved by both Customer and Employee? And the cascade="all" makes this side-effect?
Now if I do not use the DBUtils method and do directly:
Session session = DBUtil.getSessionFactory().openSession();
Transaction tx = session.beginTransaction();
session.save(employee);
session.save(customer);
tx.commit();
session.close();
Again, it works as expected. I.e. only 1 employee record is created.
What am I doing something wrong here?
UPDATE:
Hibernate mappings:
<hibernate-mapping>
<class name="database.entities.Associate" table="EMPLOYEE">
<id name="assosiateId" type="java.lang.Long">
<column name="EMPLOYEEID" />
<generator class="identity" />
</id>
<property name="firstName" type="java.lang.String" not-null="true">
<column name="FIRSTNAME" />
</property>
<property name="lastName" type="java.lang.String" not-null="true">
<column name="LASTNAME" />
</property>
<property name="userName" type="java.lang.String" not-null="true">
<column name="USERNAME" />
</property>
<property name="password" type="java.lang.String" not-null="true">
<column name="PASSWORD" />
</property>
<set name="orders" table="ORDERS" inverse="true" cascade="all" lazy="true">
<key>
<column name="EMPLOYEEID" />
</key>
<one-to-many class="database.entities.Order" />
</set>
</class>
</hibernate-mapping>
<hibernate-mapping>
<class name="database.entities.Customer" table="CUSTOMER">
<id name="customerId" type="java.lang.Long">
<column name="CUSTOMERID" />
<generator class="identity" />
</id>
<property name="customerName" type="java.lang.String">
<column name="CUSTOMERNAME" />
</property>
<set name="orders" table="ORDERS" inverse="true" cascade="all" lazy="true">
<key>
<column name="CUSTOMERID" />
</key>
<one-to-many class="database.entities.Order" />
</set>
</class>
</hibernate-mapping>
<hibernate-mapping>
<class name="database.entities.Order" table="ORDERS">
<id name="orderId" type="java.lang.Long">
<column name="ORDERID" />
<generator class="identity" />
</id>
<property name="orderDate" type="java.util.Date">
<column name="ORDERDATE" />
</property>
<property name="quantity" type="java.lang.Integer">
<column name="QUANTITY" />
</property>
<property name="quantityMargin" type="java.lang.Long">
<column name="QUANTITYMARGIN" />
</property>
<property name="port" type="java.lang.String">
<column name="PORT" />
</property>
<property name="orderState" type="java.lang.String">
<column name="ORDERSTATE" />
</property>
<many-to-one name="customer" class="database.entities.Customer" cascade="all" fetch="join">
<column name="CUSTOMERID" />
</many-to-one>
<many-to-one name="associate" column="EMPLOYEEID" class="database.entities.Employee" cascade="all" fetch="join">
</many-to-one>
</class>
</hibernate-mapping>
UDATE 2:
class Employee{
//Various members
Set<Order> orders = new HashSet<Order>();
public void addOrder(Order order){
order.setEmployee(this);
orders.add(order);
}
}
Also:
class Customer{
//Various members
Set<Order> orders = new HashSet<Order>();
public void addOrder(Order order){
order.setCustomer(this);
orders.add(order);
}
}

It seems to me that in the DBUtils code, you are wrapping both saves in an outer transaction, whereas in the Utils code, you have them in two completely separate transactions without an outer one.
Depending on your cascading, Hibernate has to figure out which objects need to be saved. When you run the Utils code, with two separate transactions, it will save the Order first. Since you're cascading all, this means it will save the Order first, then the Customer. However, you've created the SAME Order for both the Customer and Employee. Therefore, the Employee also gets saved in the first transaction (due to cascading). The second transaction, since it is separate, will not be aware of this and save another Employee.
On the other hand, if you wrap them in an outer transaction, Hibernate can figure out the identities of all the objects and save them properly.

try saving only Order instead of saving Employee and Customer separately. With your existing cascade=all setting both parent object will get saved without creating any duplicates.