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• Hibernate: how to maintain insertion order

  - by jwaddell

  I have a list of entities where creation order is important, but they do not contain a timestamp to use for sorting. Entities are added to the end of the list as they are created so they will be ordered correctly in the list itself. After persisting the list using Hibernate the entities appear in the database table in the order that they were created. However when retrieving the list using a new Hibernate session the list is now in reverse order of insertion/creation. Is this expected behaviour? Is there any way to retrieve the list in the same order as it appears in the table? The primary key is a UUID, and the list of entities should always have been created on the same IP address and JVM. This mean sorting by UUID is a possibility but I'd rather not make assumptions. Another possibility is if the list is guaranteed to always come out in reverse order I could always just work through it backwards.

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• Good design of mapping Java Domain objects to Tables (using Hibernate)

  - by M. McKenzie

  Hey guys, I have a question that is more in the realm of design, than implementation. I'm also happy for anyone to point out resources for the answer and I'll gladly, research for myself. Highly simplified Java and SQL: Say I have a business domain POJO called 'Picture' with three attributes. class Picture int idPicture String fileName long size Say I have another business domain POJO called "Item" with 3 attributes Class Item int idItem String itemName ArrayList itemPictures These would be a normal simple relationship. You could say that 'Picture' object, will never exist outside an 'Item' object. Assume a picture belongs only to a specific item, but that an item can have multiple pictures Now - using good database design (3rd Normal Form), we know that we should put items and pictures in their own tables. Here is what I assume would be correct. table Item int idItem (primary key) String itemName table Picture int idPicture (primary key) varchar(45) fileName long size int idItem (foreign key) Here is my question: If you are making Hibernate mapping files for these objects. In the data design, your Picture table needs a column to refer to the Item, so that a foreign key relation can be maintained. However,in your business domain objects - your Picture does not hold a reference/attribute to the idItem - and does not need to know it. A java Picture instance is always instantiated inside an Item instance. If you want to know the Item that the Picture belongs to you are already in the correct scope. Call myItem.getIdItem() and myItem.getItemPictures(),and you have the two pieces of information you need. I know that Hibernate tools have a generator that can auto make your POJO's from looking at your database. My problem stems from the fact that I planned out the data design for this experiment/project first. Then when I went to make the domain java objects, I realized that good design dictated that the objects hold other objects in a nested way. This is obviously different from the way that a database schema is - where all objects(tables) are flat and hold no other complex types within them. What is a good way to reconcile this? Would you: (A) Make the hibernate mapping files so that Picture.hbm.xml has a mapping to the POJO parent's idItem Field (if it's even possible) (B) Add an int attribute in the Picture class to refer to the idItem and set it at instantiation, thus simplifying the hbm.xml mapping file by having all table fields as local attributes in the class (C) Fix the database design because it is wrong, dork. I'd truly appreciate any feedback

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• Hibernate HQL to basic SQL

  - by CC

  Hello everybody, I working on a project with Hibernate and we need to replace Hibernate with some "home made persistence" stuff. The idea is that the project is big enough, and we have many HQL queries. The problem is with the queries like select a,b from table1, table2 on t1.table1=t2.table2 Basically all joins are not supported by our "hand made persistence" stuff. What I would need, is to be able to do some sort of transcoder, which will take as a input the HQL queries and output some SQL, but the basic SQL without joins, something like (a dumb example) select a from table1 where t1 IN ( select b from table2) I hope you get the idea. My persistence layer does not supports joins. Does anybody has any idea about something like that? Some framework, or something? Thanks alot everybody. C.C.

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• Query a Hibernate many-to-many association

  - by Perry Hoekstra

  In Hibernate HQL, how would you query through a many-to-many association. If I have a Company with multiple ProductLines and other companies can offer these same product lines, I have a Company entity, a ProductLine entity and an association table CompanyProductLine. In SQL, I can get what I need like this: select * from company c where c.companyId in (select companyId from companyProductLine cpl, productline pl where cpl.productLineId = pl.productLineId and pl.name= 'some value'); My problem sees to lie with the association I defined in the Company.hbm.xml file: <set name="productLines" cascade="save-update" table="CompanyProductLine"> <key column="companyId"/> <many-to-many class="com.foo.ProductLine" column="productLineId" /> </set> Any HQL I seem to come up with will throw a: 'expecting 'elements' or 'indices"' Hibernate exception. Thoughts on what the proper HQL would be?

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• Spring + Hibernate + JPA

  - by Albinoswordfish

  As of now I have a working Spring application with persistence. However now I want to use Hibernate with JPA to do all of my database activities. I want to do this using an entitymanager. I've been reading many documents and tutorials on this matter, I've been getting confused on whether I need a persistence.xml file or not. Also I've been getting confused on how to setup my applicationContext.xml file as well. Does anybody know of a good site to look at in order to learn Spring + Hibernate + JPA + using EntityManager?

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• Usual hibernate performance pitfall

  - by Antoine Claval

  Hi, We have just finish to profile our application. ( she's begin to be slow ). the problem seems to be "in hibernate". It's a legacy mapping. Who work's, and do it's job. The relational shema behind is ok too. But some request are slow as hell. So, we would appreciate any input on common and usual mistake made with hibernate who end up with slow response. Exemple : Eager in place of Lazy can change dramaticly the response time....

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• Hibernate and Child Objects (add versus clear)

  - by tyndall

  Lets say I have domain model with Automobile and Wheels. Wheels is a List of Wheels Wheels has a many-to-one relationship to Automobile. If I get an object back from Hibernate and it has 4 wheels. I take that object remove the 4 wheels and add 4. And then Save. If I ask Hibernate for the object again and it returns an auto with 8 wheels... what are we doing wrong? I don't have access to the source for a few days but want to give our Java devs a push in the right direction. Thanks.

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• Seam + hibernate + jsf on weblogic

  - by Kiva

  I'm making a little project with Seam, Hibernate and JSF. This project run on JBoss 5.1. My boss wants to deploy this project on WebLogic. I read on the seam documentation that seam and WebLogic don't work fine together. I would like to know if I can use Hibernate (with JPA) and JSF on WebLogic and what framework (struts, spring?) I can use to replace Seam. Edit: I read in the seam documentation (chapter 39, weblogic integration) and I find that: For several releases of Weblogic there has been an issue with how Weblogic generates stubs and compiles EJB's that use variable arguments in their methods. This is confirmed in the Weblogic 9.X and 10.0.MP1 versions. Unfortunately the 10.3 version only partially addresses the issue as detailed below. So, I want to know if other problems like this exist. Edit 2: I use Weblogic 10.3

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• How to specify connection release modes in Hibernate?

  - by ajay

  How to specify connection release modes in Hibernate? Thanks,

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• Hibernate Hql find result size for paginator

  - by KCore

  Hi, I need to add paginator for my Hibernate application. I applied it to some of my database operations which I perform using Criteria by setting Projection.count().This is working fine. But when I use hql to query, I can't seem to get and efficient method to get the result count. If I do query.list().size() it takes lot of time and I think hibernate does load all the objects in memory. Can anyone please suggest an efficient method to retrieve the result count when using hql?

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• Basic Hibernate question using and sql query

  - by Aerosteak

  Hello Sorry if this is basic but I cannot find the solution anywhere. I have an java Object ‘Person’ with 3 properties firstname,lastname and username. I have an Oracle Store procedure returning a Resultset with the 3 column. All works fine for that. Now I have another StoreProcedure that will only return firstname and lastname but not username. I get the following error : « could not read column value from result set username. » Hibernate tries to fetch the username property from the resultset. If I remove the property username, then it works. Do I have to Create a Special Pojo for Each type of resultset or can I tell Hibernate what to map for each result set? Please help.

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• Hibernate Persistence problems with Bean Mapping (Dozer)

  - by BuffaloBuffalo

  I am using Hibernate 3, and having a particular issue when persisting a new Entity which has an association with an existing detached entity. Easiest way to explain this is via code samples. I have two entities, FooEntity and BarEntity, of which a BarEntity can be associated with many FooEntity: @Entity public class FooEntity implements Foo{ @Id private Long id; @ManyToOne(targetEntity = BarEntity.class) @JoinColumn(name = "bar_id", referencedColumnName = "id") @Cascade(value={CascadeType.ALL}) private Bar bar; } @Entity public class BarEntity implements Bar{ @Id private Long id; @OneToMany(mappedBy = "bar", targetEntity = FooEntity.class) private Set<Foo> foos; } Foo and Bar are interfaces that loosely define getters for the various fields. There are corresponding FooImpl and BarImpl classes that are essentially just the entity objects without the annotations. What I am trying to do is construct a new instance of FooImpl, and persist it after setting a number of fields. The new Foo instance will have its 'bar' member set to an existing Bar (runtime being a BarEntity) from the database (retrieved via session.get(..)). After the FooImpl has all of its properties set, Apache Dozer is used to map between the 'domain' object FooImpl and the Entity FooEntity. What Dozer is doing in the background is instantiating a new FooEntity and setting all of the matching fields. BarEntity is cloned as well via instantiation and set the FooEntity's 'bar' member. After this occurs, passing the new FooEntity object to persist. This throws the exception: org.hibernate.PersistentObjectException: detached entity passed to persist: com.company.entity.BarEntity Below is in code the steps that are occurring FooImpl foo = new FooImpl(); //returns at runtime a persistent BarEntity through session.get() Bar bar = BarService.getBar(1L); foo.setBar(bar); ... //This constructs a new instance of FooEntity, with a member 'bar' which itself is a new instance that is detached) FooEntity entityToPersist = dozerMapper.map(foo, FooEntity.class); ... session.persist(entityToPersist); I have been able to resolve this issue by either removing or changing the @Cascade annotation, but that limits future use for say adding a new Foo with a new Bar attached to it already. Is there some solution here I am missing? I would be surprised if this issue hasn't been solved somewhere before, either by altering how Dozer Maps the children of Foo or how Hibernate reacts to a detached Child Entity.

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• Hibernate - join un related objects

  - by CuriousMind

  I have a requirement, wherein I have to join two unrelated objects using Hibernate HQL. Here is the sample POJO class class Product{ int product_id; String name; String description; } and Class Item{ int item_id; String name; String description; int quantity; int product_id; //Note that there is no composed product object. } Now I want to perform a query like select * from Product p left outer join Item i on p.product_id = i.item_id I want a multidimensional array as an output of this query so that I can have separate instances of Product and Item, instead of one composed in another. Is there any way to do this in Hibernate?

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• Accessing inter-schema tables and relations in hibernate

  - by nitesh

  There is a typical situation being faced where different tables are scattered through different schemas in Oracle database and they are related to each other (encompassing all different types of relations). How can they be represented in Hibernate using annotations as when a sessionfactory handle is created for one schema, tables in that schema can't access other related tables (foreign key relation to tables in other schema)? For a query like following, exception is thrown - "from table1 as model where model.table2Name.table2column = "+foo Exception comes as - org.hibernate.QueryException: could not resolve property: table2column of: com.test.table1 [from com.test.table1 as model where model.table2Name.table2column = 1] Here table1 and table2 are present in different schemas.

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• Hibernate Unit tests - Reset schema

  - by Marco

  Hi, I'm testing the CRUD operations of my DAOs in JUnit tests. When i execute the single test, Hibernate always resets the schema and populates the DB in a known state. But when i execute multiple tests in a row, Hibernate resets the schema once, and then the data is accumulated during the execution of the tests. This is an unexpected behavior, so I'd like to add in the @Before method of the tests a function that explicitly resets the schema to avoid the pesistence of side data created by previous tests during the execution chain. Any tips? Thanks

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• Hibernate/Spring: getHibernateTemplate().save(...) Freezes/Hangs

  - by ashes999

  I'm using Hibernate and Spring with the DAO pattern (all Hibernate dependencies in a *DAO.java class). I have nine unit tests (JUnit) which create some business objects, save them, and perform operations on them; the objects are in a hash (so I'm reusing the same objects all the time). My JUnit setup method calls my DAO.deleteAllObjects() method which calls getSession().createSQLQuery("DELETE FROM <tablename>").executeUpdate() for my business object table (just one). One of my unit tests (#8/9) freezes. I presumed it was a database deadlock, because the Hibernate log file shows my delete statement last. However, debugging showed that it's simply HibernateTemplate.save(someObject) that's freezing. (Eclipse shows that it's freezing on HibernateTemplate.save(Object), line 694.) Also interesting to note is that running this test by itself (not in the suite of 9 tests) doesn't cause any problems. How on earth do I troubleshoot and fix this? Also, I'm using @Entity annotations, if that matters. Edit: I removed reuse of my business objects (use unique objects in every method) -- didn't make a difference (still freezes). Edit: This started trickling into other tests, too (can't run more than one test class without getting something freezing) Transaction configuration: <bean id="txManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager"> <property name="dataSource" ref="dataSource" /> </bean> <tx:advice id="txAdvice" transaction-manager="txManager"> <!-- the transactional semantics... --> <tx:attributes> <!-- all methods starting with 'get' are read-only --> <tx:method name="get*" read-only="true" /> <tx:method name="find*" read-only="true" /> <!-- other methods use the default transaction settings (see below) --> <tx:method name="*" /> </tx:attributes> </tx:advice> <!-- my bean which is exhibiting the hanging behavior --> <aop:config> <aop:pointcut id="beanNameHere" expression="execution(* com.blah.blah.IMyDAO.*(..))" /> <aop:advisor advice-ref="txAdvice" pointcut-ref="beanNameHere" /> </aop:config>

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• Java Hibernate Lazy=false

  - by Noor

  When setting Lazy=false, then hibernate will automatically loads the objects into the required sets e.g. <set name="Options" table="ATTRIBUTEOPTION" inverse="false" cascade="all" lazy="false"> <key> <column name="ATTRIBUTEID" /> </key> <one-to-many class="com.BiddingSystem.Models.AttributeOption" /> </set> but if in my xml mapping, I place lazy=true and in some place in my application i decide that i want to load all attribute options, should i do it manually, or is there a technique which lets tells hibernate that now i want to set lazy=false??

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• hibernate annotation- extending base class - values are not being set - strange error

  - by gt_ebuddy

  I was following Hibernate: Use a Base Class to Map Common Fields and openjpa inheritance tutorial to put common columns like ID, lastModifiedDate etc in base table. My annotated mappings are as follow : BaseTable : @MappedSuperclass public abstract class BaseTable { @Id @GeneratedValue @Column(name = "id") private int id; @Column(name = "lastmodifieddate") private Date lastModifiedDate; ... Person table - @Entity @Table(name = "Person ") public class Person extends BaseTable implements Serializable{ ... Create statement generated : create table Person (id integer not null auto_increment, lastmodifieddate datetime, name varchar(255), primary key (id)) ; After I save a Person object to db, Person p = new Person(); p.setName("Test"); p.setLastModifiedDate(new Date()); .. getSession().save(p); I am setting the date field but, it is saving the record with generated ID and LastModifiedDate = null, and Name="Test". Insert Statement : insert into Person (lastmodifieddate, name) values (?, ?) binding parameter [1] as [TIMESTAMP] - <null> binding parameter [2] as [VARCHAR] - Test Read by ID query : When I do hibernate query (get By ID) as below, It reads person by given ID. Criteria c = getSession().createCriteria(Person.class); c.add(Restrictions.eq("id", id)); Person person= c.list().get(0); //person has generated ID, LastModifiedDate is null select query select person0_.id as id8_, person0_.lastmodifieddate as lastmodi8_, person0_.name as person8_ from Person person0_ - Found [1] as column [id8_] - Found [null] as column [lastmodi8_] - Found [Test] as column [person8_] ReadAll query : //read all Query query = getSession().createQuery("from " + Person.class.getName()); List allPersons=query.list(); Corresponding SQL for read all select query select person0_.id as id8_, person0_.lastmodifieddate as lastmodi8_, person0_.name as person8_ from Person person0_ - Found [1] as column [id8_] - Found [null] as column [lastmodi8_] - Found [Test] as column [person8_] - Found [2] as column [id8_] - Found [null] as column [lastmodi8_] - Found [Test2] as column [person8_] But when I print out the list in console, its being more weird. it is selecting List of Person object with ID fields = all 0 (why all 0 ?) LastModifiedDate = null Name fields have valid values I don't know whats wrong here. Could you please look at it? FYI, My Hibernate-core version : 4.1.2, MySQL Connector version : 5.1.9 . In summary, There are two issues here Why I am getting All ID Fields =0 when using read all? Why the LastModifiedDate is not being inserted?

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• Hibernate - Persisting polymorphic joins

  - by Marty Pitt

  Hi I'm trying to understand how to best implement a polymorphic one-to-many in hibernate. Eg: @MappedSuperclass public class BaseEntity { Integer id; // etc... } @Entity public class Author extends BaseEntity {} @Entity public class Post extends BaseEntity {} @Entity public class Comment extends BaseEntity {} And now, I'd like to also persist audit information, with the following class: @Entity public class AuditEvent { @ManyToOne // ? BaseEntity entity; } What is the appropriate mapping for auditEvent.entity? Also, how will Hibernate actually persist this? Would a series of join tables be generated (AuditEvent_Author , AuditEvent_Post, AuditEvent_Comment), or is there a better way? Note, I'd rather not have my other entity classes expose the other side of the join (eg., List<AuditEvent> events on BaseEntity) - but if that's the cleanest way to implement, then it will suffice.

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• hibernate - Postgres- target lists can have at most 1664 entries

  - by Vineyard

  We are using hibernate, postgres 8.3x Our entities are many to one mapped with eager fetching. We have multiple associations with Many to one mapping. As we added new columns to any other existing entities, We are getting below error: target lists can have at most 1664 entries I searched internet and they say this is due to More number of select statements in sql query (generated by hibernate) Can you any body please let us know if there is any configuration (in postgres) to update max number columns in configuration or any other solution to solve this issue. Thank you in advance.

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• Hibernate Query - Get latest versions by timestamp?

  - by Slim

  I have a database that is being used as a sort of version control system. That is, instead of ever updating any rows, I add a new row with the same information. Each row also contains a version column that is a date timestamp, so the only difference is the new row will have a more recent timestamp. What I'm having trouble with is writing an efficient hibernate query to return the latest version of these rows. For the sake of example, these are rows in a table called Product, the timestamped column is version. There are multiple versions of multiple products in the table. So there may be multiple versions (rows) of ProductA, multiple versions of ProductB, etc. And I would like to grab the latest version of each. Can I do this in just a single hibernate query? session.createQuery("select product from Product product where...?"); Or would this require some intermediate steps?

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• go up to 3 level dephth in hibernate criterion

  - by Satyajitsinh Raijada

  i am using hibernate criterion for fetching results. Here with i provided demo design of my persistence class. Class A{ private B b; } Class B{ private C c; } Class C{ private Long val; } assume these are the hibernate persistence classes i am not writing all annotations of mapping with database. now my problem is i want to retrieve results of Class A according to the value of Class C's val property. i tried to fetch it using, Criteria c = Restrictions.eq("b.c.val", value); List l = c.list; it shows could not resolve property. i searched and came to know criteria wont work up to this much depth. i don't want shift to HQL. any idea??

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• Hibernate entities: columns without entity properties

  - by lewap

  Is there a way to "magically" persist a column which is not represented as a property in an entity? Concretely I want to add audit info to an entity without having the audit info on the entity. The audit values are not stored in the entity, but are retrieved from the environment at the time of persisting the entity. This happens in a AuditInfoUserType. The nullSafeSet gets the info from the SecurityContext, instead of reading from the entity. In the hibernate mapping, however, the audit info properties have to be defined. Is there a way in hibernate to define columns without properties?

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• Dump Hibernate activity to sql script file

  - by zeven

  Hi, I'm trying to log hibernate activity (only dml operations) to an sql script file. My goal is to have a way to reconstruct the database from a given starting point to the current state by executing the generated script. I can get the sql queries from log4j logs but they have more information than the raw sql queries and i would need to parse them and extract only the helpful statements. So i'm looking for a programatic way, maybe by listening the persist/merge/delete operations and accessing the hibernate-generated sql statements. I don't like to reinvent the wheel so, if anybody know a way for doing this i would appreciate it very much. Thanks in advance

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• MySQL NDB Cluster + Hibernate

  - by DD

  Does anyone know if you can use mySQL Cluster with Hibernate?

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