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  • Table cell doesn't obey vertical-align CSS declaration when it contains a floated element

    - by mikez302
    I am trying to create a table, where each cell contains a big floated h1 on the left side, and a larger amount of small text to the right of the big text, vertically centered. However, the small text is showing up at the top of each cell, despite that it has a "vertical-align: middle" declaration. When I remove the big floated element, everything looks fine. I tested it in recent versions of IE, Firefox, and Safari, and this happened in every case. Why is this happening? Does anyone know of a way around it? Here is an example: <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html><head> <meta http-equiv='Content-Type' content='text/html; charset=UTF-8'> <title>vertical-align test</title> <style type="text/css"> td { border: solid black 1px; vertical-align: middle; font-size: 12px} h1 { font-size: 40px; float: left} </style> </head> <body> <table> <tr> <td><h1>1</h1>The quick brown fox jumps over the lazy dog.</td> <td>The quick brown fox jumps over the lazy dog.</td> </tr> </table> </body></html> Notice that the small text in the first cell is at the top for some reason, but the text in the 2nd cell is vertically centered.

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  • Error: "Cannot simultaneously fetch multiple bags" when calling Configuration.BuildSessionFactory();

    - by Nick Meldrum
    We are getting this error after upgrading to NHibernate 2.1. [QueryException: Cannot simultaneously fetch multiple bags.] NHibernate.Loader.BasicLoader.PostInstantiate() +418 NHibernate.Loader.Entity.EntityLoader..ctor(IOuterJoinLoadable persister, String[] uniqueKey, IType uniqueKeyType, Int32 batchSize, LockMode lockMode, ISessionFactoryImplementor factory, IDictionary`2 enabledFilters) +123 NHibernate.Loader.Entity.BatchingEntityLoader.CreateBatchingEntityLoader(IOuterJoinLoadable persister, Int32 maxBatchSize, LockMode lockMode, ISessionFactoryImplementor factory, IDictionary`2 enabledFilters) +263 NHibernate.Persister.Entity.AbstractEntityPersister.CreateEntityLoader(LockMode lockMode, IDictionary`2 enabledFilters) +26 NHibernate.Persister.Entity.AbstractEntityPersister.CreateLoaders() +57 NHibernate.Persister.Entity.AbstractEntityPersister.PostInstantiate() +1244 NHibernate.Persister.Entity.SingleTableEntityPersister.PostInstantiate() +18 NHibernate.Impl.SessionFactoryImpl..ctor(Configuration cfg, IMapping mapping, Settings settings, EventListeners listeners) +3261 NHibernate.Cfg.Configuration.BuildSessionFactory() +87 Without stepping into the NHibernate source, it doesn't look like I can see which mapping is creating the issue. It's a very old application with a load of mappings files, lots of mappings have one-to-many bags in them, all lazy instantiated. For example: <bag name="Ownership" lazy="true" cascade="all" inverse="true" outer-join="auto" where="fkOwnershipStatusID!=6"> <key column="fkStakeHolderID"/> <one-to-many class="StakeholderLib.Ownership,StakeholderLib" /> </bag> maps to: public virtual IList Ownership { get { if (ownership == null) ownership = new ArrayList(); return ownership; } set { ownership = value; } } Has anyone seen this error before when upgrading to NHibernate 2.1?

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  • How to store dynamic references to parts of a text

    - by Antoine L
    In fact, my question concerns an algorithm. I need to be able to attach annotations to certain parts of a text, like a word or a group of words. The first thing that came to me to do so is to store the position of this part (indexes) in the text. For instance, in the text 'The quick brown fox jumps over the lazy dog', I'd like to attach an annotation to 'quick brown fox', so the indexes of the annotation would be 4 - 14. But since the text is editable (other annotations could provoke a modification from text's author), the annoted part is likely to move (the indexes could change). In fact, I don't know how to update the indexes of the annoted part. What if the text becomes 'Everyday, the quick brown fox jumps over the lazy dog' ? I guess I have to watch every change of the text in the front-end application ? The front-end part of the application will be HTML with Javascript. I will be using PHP to develop the back-end part and every text and annotation will be stored in a database.

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  • Nhibernate fires SQL commands

    - by Chris
    Hi all, when updating an entity A, NHibernate also send an SQL update command for some other entity B. A and B are not related. Just before saving entity A, the parent of entity B is loaded via a SQLQuery. Then, when accessed, B is lazy loaded (part of a collection). If I save entity A an update statement for entity B is generated as well. How can that be, that when saving an entity, another entity loaded before but is not related to the entity saved, is updated as well?! Can I somehow track where the update comes from? Btw. I am using an save event listener. Could it be that this is always triggered for entity loaded, even though they are not saved explicitly? public class EntitySaveEventListener : NHibernate.Event.Default.DefaultSaveEventListener { protected override object PerformSaveOrUpdate(SaveOrUpdateEvent e) { //auditing return base.PerformSaveOrUpdate(e); } } Update (sorry for providing not enough info): I tracked it down a bit. A select stateement on a entity called address is executed (is it lazy loaded by a parent). Then I create a new entity called Request. Right before saving this entity a session flush is called which updates the address, even though I did not call save or update on the address. Address is a collection within Request. <class name="Request" table="Request"> <bag name="addresses" access="field" cascade="all-delete-orphan" where="IsDeleted = 0"> <key column="RequestId"/> <one-to-many class="Address"/> </bag> ... // address is fetched only NHibernate.SQL: 2010-02-17 11:47:21,306 [21] DEBUG NHibernate.SQL [(null)] - SELECT addresses0_.RequestId as ServiceP8_3_, .... // session flushed here // address is updated NHibernate.SQL: 2010-02-17 11:47:34,306 [21] DEBUG NHibernate.SQL [(null)] - Batch commands: command 0:UPDATE Address SET Street = @p0, ..... Would the address be updated automatically when it is manipulated somehow even though it is not explicitly saved via it's parent (cascade)?

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  • JPA concatenating table names for parent/child @OneToMany

    - by Robert
    We are trying to use a basic @OneToMany relationship: @Entity @Table(name = "PARENT_MESSAGE") public class ParentMessage { @Id @Column(name = "PARENT_ID") @GeneratedValue(strategy = GenerationType.IDENTITY) private Integer parentId; @OneToMany(fetch=FetchType.LAZY) private List childMessages; public List getChildMessages() { return this.childMessages; } ... } @Entity @Table(name = "CHILD_MSG_USER_MAP") public class ChildMessage { @Id @Column(name = "CHILD_ID") @GeneratedValue(strategy = GenerationType.IDENTITY) private Integer childId; @ManyToOne(optional=false,targetEntity=ParentMessage.class,cascade={CascadeType.REFRESH}, fetch=FetchType.LAZY) private ParentMessage parentMsg; public ParentMessage getParentMsg() { return parentMsg; } ... } ChildMessage child = new ChildMessage(); em.getTransaction().begin(); ParentMessage parentMessage = (ParentMessage) em.find(ParentMessage.class, parentId); child.setParentMsg(parentMessage); List list = parentMessage.getChildMessages(); if(list == null) list = new ArrayList(); list.add(child); em.getTransaction().commit(); We receive the following error. Why is OpenJPA concatenating the table names to APP.PARENT_MESSAGE_CHILD_MSG_USER_MAP? Of course that table doesn't exist.. the tables defined are APP.PARENT_MESSAGE and APP.CHILD_MSG_USER_MAP Caused by: org.apache.openjpa.lib.jdbc.ReportingSQLException: Table/View 'APP.PARENT_MESSAGE_CHILD_MSG_USER_MAP' does not exist. {SELECT t1.CHILD_ID, t1.PARENT_ID, t1.CREATED_TIME, t1.USER_ID FROM APP.PARENT_MESSAGE_CHILD_MSG_USER_MAP t0 INNER JOIN APP.CHILD_MSG_USER_MAP t1 ON t0.CHILDMESSAGES_CHILD_ID = t1.CHILD_ID WHERE t0.PARENTMESSAGE_PARENT_ID = ?} [code=30000, state=42X05]

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  • Remove then Query fails in JPA (deleted entity passed to persist)

    - by nag
    I have two entitys MobeeCustomer and CustomerRegion i want to remove the object from CustomerRegion first Im put join Coloumn in CustomerRegion is null then Remove the Object from the entityManager but Iam getting Exception MobeeCustomer: public class MobeeCustomer implements Serialization{ private Long id; private String custName; private String Address; private String phoneNo; private Set<CustomerRegion> customerRegion = new HashSet<CustomerRegion>(0); @OneToMany(cascade = { CascadeType.PERSIST, CascadeType.REMOVE }, fetch = FetchType.LAZY, mappedBy = "mobeeCustomer") public Set<CustomerRegion> getCustomerRegion() { return CustomerRegion; } public void setCustomerRegion(Set<CustomerRegion> customerRegion) { CustomerRegion = customerRegion; } } CustomerRegion public class CustomerRegion implements Serializable{ private Long id; private String custName; private String description; private String createdBy; private Date createdOn; private String updatedBy; private Date updatedOn; private MobeeCustomer mobeeCustomer; @ManyToOne(fetch = FetchType.LAZY) @JoinColumn(name = "MOBEE_CUSTOMER") public MobeeCustomer getMobeeCustomer() { return mobeeCustomer; } public void setMobeeCustomer(MobeeCustomer mobeeCustomer) { this.mobeeCustomer = mobeeCustomer; } } sample code: for (CustomerRegion region : deletedRegionList) { region.setMobeeCustomer(null); getEntityManager().remove(region); } StackTrace: please suggest me how to remove the CustomerRegion Object I am getting Exception javax.persistence.EntityNotFoundException: deleted entity passed to persist: [com.manam.mobee.persist.entity.CustomerRegion#<null>] 15:46:34,614 ERROR [STDERR] at org.hibernate.ejb.AbstractEntityManagerImpl.throwPersistenceException(AbstractEntityManagerImpl.java:613) 15:46:34,614 ERROR [STDERR] at org.hibernate.ejb.AbstractEntityManagerImpl.flush(AbstractEntityManagerImpl.java:299) 15:46:34,614 ERROR [STDERR] at org.jboss.seam.persistence.EntityManagerProxy.flush(EntityManagerProxy.java:92) 15:46:34,614 ERROR [STDERR] at org.jboss.seam.framework.EntityHome.update(EntityHome.java:64)

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  • Nhibernate beginner - asking for directions

    - by George
    Hello guys. I'm starting off with NHibernate now and I still don't have a testable environment. I would like to know from you, experienced fellows if there is a problem to map IList to an Set in .hbm file. Like this: //c# IList<TrechoItem> trechos_item; <!-- xml .hbm --> <set name="TrechosItem" table="trecho_item" lazy="true" inverse="true" fetch="select"> <key column="id_item"/> <one-to-many class="TrechoItem"/> </set> Or, in this: IList<Autor> Autores; <set name="Autores" lazy="true" table="item_possui_autor"> <key column="id_item"/> <many-to-many class="Autor" column="id_autor"/> </set> Is this possible? Or am I doing the wrong thing? I tried using and but these did not gave me all the options in . Thanks in advanced

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  • NHibernate many-to-many relationship does not update join-table

    - by Davide Vosti
    I'm having trouble saving a many-to-many relationship with nhibernate. I searched and looked at almost every same question in SO and google but nothing works. The single classes are update correctly but nothing is inserted in the join-table. I have 2 classes: Event and Category. The mapping is this: Event: <bag name="Categories" access="field.camelcase-underscore" table="EventCategories" inverse="true" cascade="all-delete-orphan" lazy="true"> <key column="Event"/> <many-to-many class="Category" column="Category"/> </bag> Category: <bag name="Events" table="EventCategories" access="field.camelcase-underscore" cascade="all-delete-orphan" lazy="true" > <key column="Category"/> <many-to-many class="Event" column="Event"/> </bag> I tried to swap every parameter in both mappings but nothing works... Do you know what I'm doing wrong or have a right mapping for this case? Thank you very much!

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  • How to iterate JPA collections in Google App engine

    - by palto
    Hi I use Google App Engine with datanucleus and JPA. I'm having a real hard time grasping how I'm supposed to read stuff from data store and pass it to JSP. If I load a list of POJOs with entitymanager and pass it to JSP, it crashes to org.datanucleus.exceptions.NucleusUserException: Object Manager has been closed. I understand why this is happening. Obviously because I fetch the list, close the entity manager and pass it to JSP, at which point it will fail because the list is lazy. How do I make the list NOT lazy without resorting to hacks like calling size() or something like that? Here is what I'm trying to do: @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { req.setAttribute("parties", getParties()); RequestDispatcher dispatcher = getServletContext().getRequestDispatcher("/WEB-INF/parties.jsp"); dispatcher.forward(req, resp); } private List<Party> getParties(){ EntityManager em = entityManagerProvider.get(); try{ Query query = em.createQuery("SELECT p FROM Party p"); return query.getResultList(); }finally{ em.close(); } }

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  • How can i mock or test my deferred execution functionality?

    - by cottsak
    I have what could be seen as a bizarre hybrid of IQueryable<T> and IList<T> collections of domain objects passed up my application stack. I'm trying to maintain as much of the 'late querying' or 'lazy loading' as possible. I do this in two ways: By using a LinqToSql data layer and passing IQueryable<T>s through by repositories and to my app layer. Then after my app layer passing IList<T>s but where certain elements in the object/aggregate graph are 'chained' with delegates so as to defer their loading. Sometimes even the delegate contents rely on IQueryable<T> sources and the DataContext are injected. This works for me so far. What is blindingly difficult is proving that this design actually works. Ie. If i defeat the 'lazy' part somewhere and my execution happens early then the whole thing is a waste of time. I'd like to be able to TDD this somehow. I don't know a lot about delegates or thread safety as it applies to delegates acting on the same source. I'd like to be able to mock the DataContext and somehow trace both methods of deferring (IQueryable<T>'s SQL and the delegates) the loading so that i can have tests that prove that both functions are working at different levels/layers of the app/stack. As it's crucial that the deferring works for the design to be of any value, i'd like to see tests fail when i break the design at a given level (separate from the live implementation). Is this possible?

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  • NHibernate - Retrieving Lots of Data Becomes Exponentially Slow

    - by nfplee
    Hi, I have an issue when I retrieve lots of data in NHibernate (such as when producing a report) the page becomes exponentially slower the more data it has to retrieve. I found the following article: http://nhforge.org/blogs/nhibernate/archive/2008/10/30/bulk-data-operations-with-nhibernate-s-stateless-sessions.aspx It explains how doing bulk data operations in NHibernate is slow since the first level cache grows too large and how you should use the IStatelessSession instead. The trouble I have is that I don't wish to tie my application to NHibernate so I've added a wrapper around ISession. I then use Linq as my query mechanism but IStatelessSession does not support Linq (it may do in NHibernate 3 but the Linq provider is not stable as it stands at the moment). I then read that you could do a clear after so many iterations to clear out the first level cache. The problem now is that you can't use lazy loading. The linq provider doesn't allow you to override the mapping defined (or eagerly fetch the additional data) so whenever I grab data which is lazy loaded after I have cleared the session an exception is thrown. I'm completely lost on what do now. I like the ease of producing reports with linq but the limitations of the inbuilt linq provider in NHibernate seem to be holding me back. I'd really appreciate it if someone could show me an alternative approach. Thanks

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  • Nhibernate + Gridview + TargetInvocationException

    - by Scott
    For our grid views, we're setting the data sources as a list of results from an Nhibernate query. We're using lazy loading, so the objects are actually proxied... most of the time. In some instances the list will consist of types of Student and Composition_Aop_Proxy_jklasjdkl31231, which implements the same members as the Student class. We've still got the session open, so the lazy loading would resolve fine, if GridView didn't throw an error about the different types in the gridview. Our current workaround is to clone the object, which results in fetching all of the data that can be lazily loaded, even though most of it won't be accessed.. ever. This, however, converts the proxy into an actual object and the grid view is happy. The performance implications kind of scare me as we're getting closer to rolling the code out as is. I've tried evicting the object after a save, which should ensure that everything is a proxy, but this doesn't seem like a good idea either. Does anyone have any suggestions/workarounds?

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  • How to get the set of beans that are to be created in Spring?

    - by cyborg
    So here's the scenario: I have a Spring XML configuration with some lazy-beans, some not lazy-beans and some beans that depend on other beans. Eventually Spring will resolve all this so that only the beans that are meant to be created are created. The question: how can I programmatically tell what this set is? When I use context.getBean(name) that initializes the bean. BeanDefinition.isLazyInit() will only tell me how I defined the bean. Any other ideas? ETA: In DefaultListableBeanFactory: public void preInstantiateSingletons() throws BeansException { if (this.logger.isInfoEnabled()) { this.logger.info("Pre-instantiating singletons in " + this); } synchronized (this.beanDefinitionMap) { for (Iterator it = this.beanDefinitionNames.iterator(); it.hasNext();) { String beanName = (String) it.next(); RootBeanDefinition bd = getMergedLocalBeanDefinition(beanName); if (!bd.isAbstract() && bd.isSingleton() && !bd.isLazyInit()) { if (isFactoryBean(beanName)) { FactoryBean factory = (FactoryBean) getBean(FACTORY_BEAN_PREFIX + beanName); if (factory instanceof SmartFactoryBean && ((SmartFactoryBean) factory).isEagerInit()) { getBean(beanName); } } else { getBean(beanName); } } } } } The set of instantiable beans is initialized. When initializing this set any beans not in this set referenced by this set will also be created. From looking through the source it does not look like there's going to be any easy way to answer my question.

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  • JPA returning null for deleted items from a set

    - by Jon
    This may be related to my question from a few days ago, but I'm not even sure how to explain this part. (It's an entirely different parent-child relationship.) In my interface, I have a set of attributes (Attribute) and valid values (ValidValue) for each one in a one-to-many relationship. In the Spring MVC frontend, I have a page for an administrator to edit these values. Once it's submitted, if any of these fields (as <input> tags) are blank, I remove the ValidValue object like so: Set<ValidValue> existingValues = new HashSet<ValidValue>(attribute.getValidValues()); Set<ValidValue> finalValues = new HashSet<ValidValue>(); for(ValidValue validValue : attribute.getValidValues()) { if(!validValue.getValue().isEmpty()) { finalValues.add(validValue); } } existingValues.removeAll(finalValues); for(ValidValue removedValue : existingValues) { getApplicationDataService().removeValidValue(removedValue); } attribute.setValidValues(finalValues); getApplicationDataService().modifyAttribute(attribute); The problem is that while the database is updated appropriately, the next time I query for the Attribute objects, they're returned with an extra entry in their ValidValue set -- a null, and thus, the next time I iterate through the values to display, it shows an extra blank value in the middle. I've confirmed that this happens at the point of a merge or find, at the point of "Execute query ReadObjectQuery(entity.Attribute). Here's the code I'm using to modify the database (in the ApplicationDataService): public void modifyAttribute(Attribute attribute) { getJpaTemplate().merge(attribute); } public void removeValidValue(ValidValue removedValue) { ValidValue merged = getJpaTemplate().merge(removedValue); getJpaTemplate().remove(merged); } Here are the relevant parts of the entity classes: Entity @Table(name = "attribute") public class Attribute { @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "attribute") private Set<ValidValue> validValues = new HashSet<ValidValue>(0); } @Entity @Table(name = "valid_value") public class ValidValue { @ManyToOne(fetch = FetchType.LAZY) @JoinColumn(name = "attr_id", nullable = false) private Attribute attribute; }

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  • How to make Spring load a JDBC Driver BEFORE initializing Hibernate's SessionFactory?

    - by Bill_BsB
    I'm developing a Spring(2.5.6)+Hibernate(3.2.6) web application to connect to a custom database. For that I have custom JDBC Driver and Hibernate Dialect. I know for sure that these custom classes work (hard coded stuff on my unit tests). The problem, I guess, is with the order on which things get loaded by Spring. Basically: Custom Database initializes Spring load beans from web.xml Spring loads ServletBeans(applicationContext.xml) Hibernate kicks in: shows version and all the properties correctly loaded. Hibernate's HbmBinder runs (maps all my classes) LocalSessionFactoryBean - Building new Hibernate SessionFactory DriverManagerConnectionProvider - using driver: MyCustomJDBCDriver at CustomDBURL I get a SQLException: No suitable driver found for CustomDBURL Hibernate loads the Custom Dialect My CustomJDBCDriver finally gets registered with DriverManager (log messages) SettingsFactory runs SchemaExport runs (hbm2ddl) I get a SQLException: No suitable driver found for CustomDBURL (again?!) Application get successfully deployed but there are no tables on my custom Database. Things that I tried so far: Different techniques for passing hibernate properties: embedded in the 'sessionFactory' bean, loaded from a hibernate.properties file. Nothing worked but I didn't try with hibernate.cfg.xml file neither with a dataSource bean yet. MyCustomJDBCDriver has a static initializer block that registers it self with the DriverManager. Tried different combinations of lazy initializing (lazy-init="true") of the Spring beans but nothing worked. My custom JDBC driver should be the first thing to be loaded - not sure if by Spring but...! Can anyone give me a solution for this or maybe a hint for what else I could try? I can provide more details (huge stack traces for instance) if that helps. Thanks in advance.

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  • Does this copy the reference or the object?

    - by Water Cooler v2
    Sorry, I am being both thick and lazy, but mostly lazy. Actually, not even that. I am trying to save time so I can do more in less time as there's a lot to be done. Does this copy the reference or the actual object data? public class Foo { private NameValueCollection _nvc = null; public Foo( NameValueCollection nvc) { _nvc = nvc; } } public class Bar { public static void Main() { NameValueCollection toPass = new NameValueCollection(); new Foo( toPass ); // I believe this only copies the reference // so if I ever wanted to compare toPass and // Foo._nvc (assuming I got hold of the private // field using reflection), I would only have to // compare the references and wouldn't have to compare // each string (deep copy compare), right? } I think I know the answer for sure: it only copies the reference. But I am not even sure why I am asking this. I guess my only concern is, if, after instantiating Foo by calling its parameterized ctor with toPass, if I needed to make sure that the NVC I passed as toPass and the NVC private field _nvc had the exact same content, I would just need to compare their references, right?

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  • Nhibernate Cannot delete the child object

    - by Daoming Yang
    I know it has been asked for many times, i also have found a lot of answers on this website, but i just cannot get out this problem. Can anyone help me with this piece of code? Many thanks. Here is my parent mapping file <set name="ProductPictureList" table="[ProductPicture]" lazy="true" order-by="DateCreated" inverse="true" cascade="all-delete-orphan" > <key column="ProductID"/> <one-to-many class="ProductPicture"/> </set> Here is my child mapping file <class name="ProductPicture" table="[ProductPicture]" lazy="true"> <id name="ProductPictureID"> <generator class="identity" /> </id> <property name="ProductID" type="Int32"></property> <property name="PictureName" type="String"></property> <property name="DateCreated" type="DateTime"></property> </class> Here is my c# code var item = _productRepository.Get(productID); var productPictrue = item.ProductPictureList .OfType<ProductPicture>() .Where(x => x.ProductPictureID == productPictureID); // reomve the finding item var ok = item.ProductPictureList.Remove(productPictrue); _productRepository.SaveOrUpdate(item); ok is false value and this child object is still in my database.

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  • Is the 'var' keyword bad? Or am I just old school?

    - by WaggingSiberian
    Recently I overheard junior developer ask "why do you use 'var' so much?". The mid-level developer responded "I use VAR all the time. I love it! I don't have to figure out the type." I didn't have the time or energy to get into a religious war and hey, I'm still the new guy here :-) I understand var has its place. LINQ comes to mind. But I have also always been told the use of var represents lazy programming and I should just use the correct type to begin with. If it's an int, define it as an int, not a var. When reviewing code, seeing the type makes it easier to follow. My opinion is, it's just lazy but there are exceptions. Var also reminds me of the VB/VBA variant type. It also had its place. I recall (from many years ago) its usage being less-than-desirable type and it was rather resource hungry. Am I just being stuck in my ways? Should we start using var all the time as my co-worker does?

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  • Why is the 'var' keyword bad? Or am I just old school?

    - by WaggingSiberian
    Recently I overheard junior developer ask "why do you use 'var' so much?". The mid-level developer responded "I use VAR all the time. I love it! I don't have to figure out the type." I didn't have the time or energy to get into a religious war and hey, I'm still the new guy here :-) I understand var has its place. LINQ comes to mind. But I have also always been told the use of var represents lazy programming and I should just use the correct type to begin with. If it's an int, define it as an int, not a var. When reviewing code, seeing the type makes it easier to follow. My opinion is, it's just lazy but there are exception. Var also reminds me of the VB/VBA variant type. It also had its place. I recall (from many years ago) its usage being less-than-desirable type and it was rather resource hungry. Am I just being stuck in my ways? Should we start using var all the time as my co-worker does?

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  • Differences Between NHibernate and Entity Framework

    - by Ricardo Peres
    Introduction NHibernate and Entity Framework are two of the most popular O/RM frameworks on the .NET world. Although they share some functionality, there are some aspects on which they are quite different. This post will describe this differences and will hopefully help you get started with the one you know less. Mind you, this is a personal selection of features to compare, it is by no way an exhaustive list. History First, a bit of history. NHibernate is an open-source project that was first ported from Java’s venerable Hibernate framework, one of the first O/RM frameworks, but nowadays it is not tied to it, for example, it has .NET specific features, and has evolved in different ways from those of its Java counterpart. Current version is 3.3, with 3.4 on the horizon. It currently targets .NET 3.5, but can be used as well in .NET 4, it only makes no use of any of its specific functionality. You can find its home page at NHForge. Entity Framework 1 came out with .NET 3.5 and is now on its second major version, despite being version 4. Code First sits on top of it and but came separately and will also continue to be released out of line with major .NET distributions. It is currently on version 4.3.1 and version 5 will be released together with .NET Framework 4.5. All versions will target the current version of .NET, at the time of their release. Its home location is located at MSDN. Architecture In NHibernate, there is a separation between the Unit of Work and the configuration and model instances. You start off by creating a Configuration object, where you specify all global NHibernate settings such as the database and dialect to use, the batch sizes, the mappings, etc, then you build an ISessionFactory from it. The ISessionFactory holds model and metadata that is tied to a particular database and to the settings that came from the Configuration object, and, there will typically be only one instance of each in a process. Finally, you create instances of ISession from the ISessionFactory, which is the NHibernate representation of the Unit of Work and Identity Map. This is a lightweight object, it basically opens and closes a database connection as required and keeps track of the entities associated with it. ISession objects are cheap to create and dispose, because all of the model complexity is stored in the ISessionFactory and Configuration objects. As for Entity Framework, the ObjectContext/DbContext holds the configuration, model and acts as the Unit of Work, holding references to all of the known entity instances. This class is therefore not lightweight as its NHibernate counterpart and it is not uncommon to see examples where an instance is cached on a field. Mappings Both NHibernate and Entity Framework (Code First) support the use of POCOs to represent entities, no base classes are required (or even possible, in the case of NHibernate). As for mapping to and from the database, NHibernate supports three types of mappings: XML-based, which have the advantage of not tying the entity classes to a particular O/RM; the XML files can be deployed as files on the file system or as embedded resources in an assembly; Attribute-based, for keeping both the entities and database details on the same place at the expense of polluting the entity classes with NHibernate-specific attributes; Strongly-typed code-based, which allows dynamic creation of the model and strongly typing it, so that if, for example, a property name changes, the mapping will also be updated. Entity Framework can use: Attribute-based (although attributes cannot express all of the available possibilities – for example, cascading); Strongly-typed code mappings. Database Support With NHibernate you can use mostly any database you want, including: SQL Server; SQL Server Compact; SQL Server Azure; Oracle; DB2; PostgreSQL; MySQL; Sybase Adaptive Server/SQL Anywhere; Firebird; SQLLite; Informix; Any through OLE DB; Any through ODBC. Out of the box, Entity Framework only supports SQL Server, but a number of providers exist, both free and commercial, for some of the most used databases, such as Oracle and MySQL. See a list here. Inheritance Strategies Both NHibernate and Entity Framework support the three canonical inheritance strategies: Table Per Type Hierarchy (Single Table Inheritance), Table Per Type (Class Table Inheritance) and Table Per Concrete Type (Concrete Table Inheritance). Associations Regarding associations, both support one to one, one to many and many to many. However, NHibernate offers far more collection types: Bags of entities or values: unordered, possibly with duplicates; Lists of entities or values: ordered, indexed by a number column; Maps of entities or values: indexed by either an entity or any value; Sets of entities or values: unordered, no duplicates; Arrays of entities or values: indexed, immutable. Querying NHibernate exposes several querying APIs: LINQ is probably the most used nowadays, and really does not need to be introduced; Hibernate Query Language (HQL) is a database-agnostic, object-oriented SQL-alike language that exists since NHibernate’s creation and still offers the most advanced querying possibilities; well suited for dynamic queries, even if using string concatenation; Criteria API is an implementation of the Query Object pattern where you create a semi-abstract conceptual representation of the query you wish to execute by means of a class model; also a good choice for dynamic querying; Query Over offers a similar API to Criteria, but using strongly-typed LINQ expressions instead of strings; for this, although more refactor-friendlier that Criteria, it is also less suited for dynamic queries; SQL, including stored procedures, can also be used; Integration with Lucene.NET indexer is available. As for Entity Framework: LINQ to Entities is fully supported, and its implementation is considered very complete; it is the API of choice for most developers; Entity-SQL, HQL’s counterpart, is also an object-oriented, database-independent querying language that can be used for dynamic queries; SQL, of course, is also supported. Caching Both NHibernate and Entity Framework, of course, feature first-level cache. NHibernate also supports a second-level cache, that can be used among multiple ISessionFactorys, even in different processes/machines: Hashtable (in-memory); SysCache (uses ASP.NET as the cache provider); SysCache2 (same as above but with support for SQL Server SQL Dependencies); Prevalence; SharedCache; Memcached; Redis; NCache; Appfabric Caching. Out of the box, Entity Framework does not have any second-level cache mechanism, however, there are some public samples that show how we can add this. ID Generators NHibernate supports different ID generation strategies, coming from the database and otherwise: Identity (for SQL Server, MySQL, and databases who support identity columns); Sequence (for Oracle, PostgreSQL, and others who support sequences); Trigger-based; HiLo; Sequence HiLo (for databases that support sequences); Several GUID flavors, both in GUID as well as in string format; Increment (for single-user uses); Assigned (must know what you’re doing); Sequence-style (either uses an actual sequence or a single-column table); Table of ids; Pooled (similar to HiLo but stores high values in a table); Native (uses whatever mechanism the current database supports, identity or sequence). Entity Framework only supports: Identity generation; GUIDs; Assigned values. Properties NHibernate supports properties of entity types (one to one or many to one), collections (one to many or many to many) as well as scalars and enumerations. It offers a mechanism for having complex property types generated from the database, which even include support for querying. It also supports properties originated from SQL formulas. Entity Framework only supports scalars, entity types and collections. Enumerations support will come in the next version. Events and Interception NHibernate has a very rich event model, that exposes more than 20 events, either for synchronous pre-execution or asynchronous post-execution, including: Pre/Post-Load; Pre/Post-Delete; Pre/Post-Insert; Pre/Post-Update; Pre/Post-Flush. It also features interception of class instancing and SQL generation. As for Entity Framework, only two events exist: ObjectMaterialized (after loading an entity from the database); SavingChanges (before saving changes, which include deleting, inserting and updating). Tracking Changes For NHibernate as well as Entity Framework, all changes are tracked by their respective Unit of Work implementation. Entities can be attached and detached to it, Entity Framework does, however, also support self-tracking entities. Optimistic Concurrency Control NHibernate supports all of the imaginable scenarios: SQL Server’s ROWVERSION; Oracle’s ORA_ROWSCN; A column containing date and time; A column containing a version number; All/dirty columns comparison. Entity Framework is more focused on Entity Framework, so it only supports: SQL Server’s ROWVERSION; Comparing all/some columns. Batching NHibernate has full support for insertion batching, but only if the ID generator in use is not database-based (for example, it cannot be used with Identity), whereas Entity Framework has no batching at all. Cascading Both support cascading for collections and associations: when an entity is deleted, their conceptual children are also deleted. NHibernate also offers the possibility to set the foreign key column on children to NULL instead of removing them. Flushing Changes NHibernate’s ISession has a FlushMode property that can have the following values: Auto: changes are sent to the database when necessary, for example, if there are dirty instances of an entity type, and a query is performed against this entity type, or if the ISession is being disposed; Commit: changes are sent when committing the current transaction; Never: changes are only sent when explicitly calling Flush(). As for Entity Framework, changes have to be explicitly sent through a call to AcceptAllChanges()/SaveChanges(). Lazy Loading NHibernate supports lazy loading for Associated entities (one to one, many to one); Collections (one to many, many to many); Scalar properties (thing of BLOBs or CLOBs). Entity Framework only supports lazy loading for: Associated entities; Collections. Generating and Updating the Database Both NHibernate and Entity Framework Code First (with the Migrations API) allow creating the database model from the mapping and updating it if the mapping changes. Extensibility As you can guess, NHibernate is far more extensible than Entity Framework. Basically, everything can be extended, from ID generation, to LINQ to SQL transformation, HQL native SQL support, custom column types, custom association collections, SQL generation, supported databases, etc. With Entity Framework your options are more limited, at least, because practically no information exists as to what can be extended/changed. It features a provider model that can be extended to support any database. Integration With Other Microsoft APIs and Tools When it comes to integration with Microsoft technologies, it will come as no surprise that Entity Framework offers the best support. For example, the following technologies are fully supported: ASP.NET (through the EntityDataSource); ASP.NET Dynamic Data; WCF Data Services; WCF RIA Services; Visual Studio (through the integrated designer). Documentation This is another point where Entity Framework is superior: NHibernate lacks, for starters, an up to date API reference synchronized with its current version. It does have a community mailing list, blogs and wikis, although not much used. Entity Framework has a number of resources on MSDN and, of course, several forums and discussion groups exist. Conclusion Like I said, this is a personal list. I may come as a surprise to some that Entity Framework is so behind NHibernate in so many aspects, but it is true that NHibernate is much older and, due to its open-source nature, is not tied to product-specific timeframes and can thus evolve much more rapidly. I do like both, and I chose whichever is best for the job I have at hands. I am looking forward to the changes in EF5 which will add significant value to an already interesting product. So, what do you think? Did I forget anything important or is there anything else worth talking about? Looking forward for your comments!

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  • windows 7 Release Condidate bi-hourly restart

    - by Revolter
    for lazy people like me who still use the Windows-7 Release Condidate until the expiration date, by now it keep "craching" every 2 hours, do anyone know a hack or something to prevent the bi-hourly restart ? i know i should upgrade etc., i just need a little more time :)

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  • Glassfish V3 won't start

    - by Zakaria
    Hi everybody, I installed NetBeans 6.8 and tried to run the GlasshFish V3 server. I'm working under Windows Vista 32 Bits. First, it won't run. Then I modified the c:\Windows\System32\drivers\etc\hosts file and put the following line into it: 127.0.0.1 localhost And when I run the GlasshFish V3 Server, no error is showing but only "INFOs" are displayed: 3 avr. 2010 19:23:19 com.sun.enterprise.glassfish.bootstrap.ASMain main INFO: Launching GlassFish on Felix platform Welcome to Felix ================ INFO: Perform lazy SSL initialization for the listener 'http-listener-2' INFO: Starting Grizzly Framework 1.9.18-k - Sat Apr 03 19:23:24 CEST 2010 INFO: Starting Grizzly Framework 1.9.18-k - Sat Apr 03 19:23:25 CEST 2010 INFO: Grizzly Framework 1.9.18-k started in: 423ms listening on port 35127 INFO: GlassFish v3 (74.2) startup time : Felix(4456ms) startup services(1709ms) total(6165ms) INFO: Grizzly Framework 1.9.18-k started in: 459ms listening on port 35116 INFO: Grizzly Framework 1.9.18-k started in: 428ms listening on port 35155 INFO: Grizzly Framework 1.9.18-k started in: 470ms listening on port 35160 INFO: Grizzly Framework 1.9.18-k started in: 513ms listening on port 35159 INFO: javassist.util.proxy.ProxyFactory.classLoaderProvider = org.glassfish.weld.WeldActivator$GlassFishClassLoaderProvider@5be8f4 INFO: Hibernate Validator bean-validator-3.0-JBoss-4.0.2 INFO: Binding RMI port to *:35165 INFO: Instantiated an instance of org.hibernate.validator.engine.resolver.JPATraversableResolver. INFO: JMXStartupService: Started JMXConnector, JMXService URL = service:jmx:rmi://PC-de-Charlotte:35165/jndi/rmi://PC-de-Charlotte:35165/jmxrmi INFO: Using com.sun.enterprise.transaction.jts.JavaEETransactionManagerJTSDelegate as the delegate INFO: [Thread[GlassFish Kernel Main Thread,5,main]] started INFO: Grizzly Framework 1.9.18-k started in: 150ms listening on port 35159 INFO: Perform lazy SSL initialization for the listener 'http-listener-2' INFO: {felix.fileinstall.poll (ms) = 5000, felix.fileinstall.dir = C:\Program Files\sges-v3\glassfish\modules\autostart, felix.fileinstall.debug = 1, felix.fileinstall.bundles.new.start = true, felix.fileinstall.tmpdir = C:\Users\CHARLO~1\AppData\Local\Temp\fileinstall-330907148519261411, felix.fileinstall.filter = null} INFO: {felix.fileinstall.poll (ms) = 5000, felix.fileinstall.dir = C:\Users\Charlotte\.netbeans\6.8\GlassFish_v3\autodeploy\bundles, felix.fileinstall.debug = 1, felix.fileinstall.bundles.new.start = true, felix.fileinstall.tmpdir = C:\Users\CHARLO~1\AppData\Local\Temp\fileinstall-2938963288421854459, felix.fileinstall.filter = null} INFO: Grizzly Framework 1.9.18-k started in: 95ms listening on port 35160 INFO: Updating configuration from org.apache.felix.fileinstall-autodeploy-bundles.cfg INFO: Installed C:\Program Files\sges-v3\glassfish\modules\autostart\org.apache.felix.fileinstall-autodeploy-bundles.cfg INFO: {felix.fileinstall.poll (ms) = 5000, felix.fileinstall.dir = C:\Users\Charlotte\.netbeans\6.8\GlassFish_v3\autodeploy\bundles, felix.fileinstall.debug = 1, felix.fileinstall.bundles.new.start = true, felix.fileinstall.tmpdir = C:\Users\CHARLO~1\AppData\Local\Temp\fileinstall-6474085409014899009, felix.fileinstall.filter = null} And there is no message such as "Glassfish started"! So, when I try to access to the admin web interface: localhost:4848 or localhost:8080 or localhost:8181 , It doesn't work. What should I do? Thank you very much, Regards.

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  • Change virtual QEMU image location

    - by dallasclark
    I've got an existing QEMU Virtual Server running on Fedora 11. Having troubles trying to find out how to change the location of where the Virtual Images are stored. Can anybody provide any help please? Thanks in advance! I'm also new to Linux Server Administration - n00b in other words - so this might seem lazy but I need to know commands or where to look

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  • URL to reboot a WebSTAR DPC2100R2 cable modem with curl?

    - by jtimberman
    Does anyone know what the magic URL is for rebooting a WebSTAR DPC2100R2 with curl? I used to have a SurfBoard, and the curl command: curl http://192.168.100.1/reset.htm?reset_modem=Restart%20Cable%20Modem Would reset the modem. Sure, I can go power cycle it manually, but it's in the basement and I'm lazy :-). I did find out the URL to elevate the access permission, but nothing about rebooting/resetting yet.

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