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  • In NHibernate (Fluent), How do you map a property on referenced object into parent object?

    - by JChristian
    I want to map the Name column from the Child table into the Parent object. How do you do this (using Fluent NHibernate)? public class Parent { public int Key { get; set; } public string ChildName { get; set; } } Tables +--------------+ +------------------+ | Parent | | Child | +--------------+ +------------------+ | Key INT | +--->| Key INT | | ChildKey INT |-----+ | Name VARCHAR(20) | +--------------+ +------------------+

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  • How to map a search object to a class with more fields with JPA annotations

    - by Moli
    Hi all, I'm a newbie with JPA. I need to map a search object to a table. The search object has only and id, name. The big object has more fileds id, name, adress and more. I use this as big object view plaincopy to clipboardprint? I use this as big object @Entity @Table(name="users") public class User { @Id @GeneratedValue(strategy = GenerationType.AUTO) private long id; private String name; private String adress; private String keywords; } //this is my search object @XXX public class UserSearch { @Id @GeneratedValue(strategy = GenerationType.AUTO) private long id; private String name; } What annotations I need to use to map the search object to the table users? I'm using spring+struts2+hibernate+JPA. Help is appreciated! Thanks!

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  • Restricting deletion with NHibernate

    - by FrontSvin
    I'm using NHibernate (fluent) to access an old third-party database with a bunch of tables, that are not related in any explicit way. That is a child tables does have parentID columns which contains the primary key of the parent table, but there are no foreign key relations ensuring these relations. Ideally I would like to add some foreign keys, but cannot touch the database schema. My application works fine, but I would really like impose a referential integrity rule that would prohibit deletion of parent objects if they have children, e.i. something similar 'ON DELETE RESTRICT' but maintained by NHibernate. Any ideas on how to approach this would be appreciated. Should I look into the OnDelete() method on the IInterceptor interface, or are there other ways to solve this? Of course any solution will come with a performance penalty, but I can live with that.

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  • rais belong_to which class to choose

    - by Small Wolf
    There is a model relation like this. class A belongs_to :ref_config,:class_name => 'User' end My question is : the A has a attribute named flag, now i want to create a function like this: if flag == 1, I want the class A like this belongs_to :ref_config,:class_name => 'Department and if flag == 2, i want the class A like this belongs_to :ref_config,:class_name => 'User' How can I implement the function Thank you!

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  • Is there an ORM with APIs to be used programatically?

    - by Kabeer
    Hello. Neither did not get any response for my previous question, nor enough views :) So here I am now framing my query afresh. Is there any ORM that offers APIs to be used programatically? In my situation, a user will be helped through a wizard to define some entities. Thereafter those entites will be created in a database in form of tables (there will of course be some improvization). I need an ORM that offers APIs for modeling and creating entities during application runtime and not just during design time. Mine is a .Net application, therefore I was looking at Entity Framework. However, to me it looked tied to Visual Studio (I may be wrong also as I am new to it). Any recommendations? Or alternative point of view?

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  • How to introduce multi-column constraint with JPA annotations?

    - by plouh
    I am trying to introduce a multi-key constraint on a JPA-mapped entity: public class InventoryItem { @Id private Long id; @Version private Long version; @ManyToOne @JoinColumn("productId") private Product product; @Column(nullable=false); private long serial; } Basically (product, serial) pair should be unique, but I only found a way to say that serial should be unique. This obviously isn't a good idea since different products might have same serial numbers. Is there a way to generate this constraint via JPA or am I forced to manually create it to DB?

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  • How to enforce DB field size limit to related Java String?

    - by Sri Sankaran
    What is the correct way to defend against trying to store more text than can be accommodated in a VARCHAR2 database field? Say the PARTNER_ROLE field of the REGISTRATIONS table is declared as VARCHAR2(80). This field is mapped in the Registration class in Java as public class Registration { @Column(name=”PARTNER_ROLE” length=”80”) private String partnerRole; } However, the setPartnerRole() method allows the user to stuff a string of any length. The problem is encountered only when one subsequently tries to insert or update the REGISTRATIONS record. Oracle complains. What is the correct way to handle this situation?

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  • Geographic obstructions in radius searches

    - by Michael Papile
    Suppose I have an application a search for all gas stations within 10 mile radius of a certain location. However one side of this location is surrounded by a mountain range that you have to drive 50 miles to get around. You would not want to return results from the other side of the mountain. What are some good algorithms/techniques to deal with such a problem? I know with point to point searches you can use path costs but I am not sure what the technique is with radius searches.

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  • Automatically Add a Prefix to Column Names for @Embeddable Classes

    - by VeeArr
    I am developing a project in which I am persisting some POJOs by adding Hibernate annotations. One problem I am running into is that code like this fails, as Hibernate tries to map the sub-fields within the Time_T onto the same column (i.e. startTime.sec and stopTime.sec both try to map to the colum sec, causing an error). @Entity public class ExampleClass { @Id long eventId; Time_T startTime; Time_T stopTime; } @Embeddable public class Time_T { int sec; int nsec; } As there will be many occurrences like this throughout the system, it would be nice if there was an option to automatically append a prefix to the column name (e.g. make the columns be startTime_sec, startTime_nsec, stopTime_sec, stopTime_nsec), without having to apply overrides on a per-field basis. Does Hibernate have this capability, or is there any other reasonable work-around?

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  • Accessing two sides of a user-user relationship in rails

    - by Lowgain
    Basically, I have a users model in my rails app, and a fanship model, to facilitate the ability for users to become 'fans' of each other. In my user model, I have: has_many :fanships has_many :fanofs, :through => :fanships In my fanship model, I have: belongs_to :user belongs_to :fanof, :class_name => "User", :foreign_key => "fanof_id" My fanship table basically consists of :id, :user_id and :fanof_id. This all works fine, and I can see what users a specific user is a fan of like: <% @user.fanofs.each do |fan| %> #things <% end %> My question is, how can I get a list of the users that are a fan of this specific user? I'd like it if I could just have something like @user.fans, but if that isn't possible what is the most efficient way of going about this? Thanks!

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  • MySQL & NHibernate. How fix the error: Column 'ReservedWord' does not belong to table ReservedWords?

    - by Eduardo Xavier
    "I am getting a weird error when using NHibernate. And I don't know what is causing this error. I am new to the whole Visual Studio and NHibernate, but not to Hibernate. I used Hibernate in the past in Java projects. Any help would be appreciated in pointing me where my error is. I am using Visual Studio 2008 SP1 with Mysql 5.1. Below is the code I am using. " The full code and examples are posted here: https://forum.hibernate.org/viewtopic.php?f=25&t=997701

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  • How much memory does a hashtable use?

    - by Michael
    Would a hashtable/hashmap use a lot of memory if it only consists of object references and int's? As for a school project we had to map a database to objects (that's what being done by orm/hibernate nowadays) but eager to find a good way not to store id's in objects in order to save them again we thought of putting all objects we created in a hashmap/hashtable, so we could easily retrieve it's ID. My question is if it would cost me performance using this, in my opinion more elegant way to solve this problem.

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  • How to map this class in NHibernate (not FluentNHibernate)?

    - by JMSA
    Suppose I have a database like this: This is set up to give role-wise menu permissions. Please note that, User-table has no direct relationship with Permission-table. Then how should I map this class against the database-tables? class User { public int ID { get; set; } public string Name { get; set; } public string Username { get; set; } public string Password { get; set; } public bool? IsActive { get; set; } public IList<Role> RoleItems { get; set; } public IList<Permission> PermissionItems { get; set; } public IList<string> MenuItemKeys { get; set; } } This means, (1) Every user has some Roles. (2) Every user has some Permissions (depending on to Roles). (3) Every user has some permitted MenuItemKeys (according to Permissions). How should my User.hbm.xml look like?

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  • Opengl ES and texcoord

    - by viraptor
    Hi, I've got some code which I would like to translate into Opengl ES. I'm not experienced with it however, so here it goes. The original code does a loop like this: glBegin(GL_TRIANGLES); for(i=0; i<num_triangles; i++) { glNormal(...); glTexCoord2f(...); glVerted3fv(...); glTexCoord2f(...); glVerted3fv(...); glTexCoord2f(...); glVerted3fv(...); } glEnd(); So that's ok - I can change the vertex handling for each triangle in the loop, into the standard: glEnableClientState (GL_VERTEX_ARRAY); glVertexPointer (3, GL_SOMETHING, 0, verts); glDrawArrays (GL_TRIANGLES, 0, 3); But how do I add the texcoord setting into this example?

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  • Hibernate subclass with foreign key relationships

    - by shikarishambu
    I need some help defining the following object hierarchy/ database relationship in Hibernate From the object sense – Agent is inherited from Person and Agency is inherited from Organization. they are inherited from Party which can have multiple Addresses associated with it The database consists of Agent - ID - Name -PartyID (references Party.ID) Agency -ID -Name -PartyID (references Party.ID) Address -AddrID -PartyID (references Party.ID) -Street Party. -PartyID

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  • Dynamic class_name for has_many relations

    - by vooD
    I'm trying to make has_many relation with dynamic class_name attribute class Category < ActiveRecord::Base has_many :ads, :class_name => ( lambda { return self.item_type } ) end or class Category < ActiveRecord::Base has_many :ads, :class_name => self.item_type end But i got errors: can't convert Proc into String or undefined method `item_type' for #<Class:0xb62c6c88> Thank you for any help!

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  • NHibernate / ORM - Child Update over Web Service

    - by tyndall
    What is the correct way to UPDATE a child object with NHibernate but not have to "awake" the parent object. Lets say you would like to try to avoid this because the parent object is large or expensive to initiate. Lets assume classes are called Author(parent) and Book(child). (still, trying to avoid instantiating Author) Book comes back over a web service as XML. It gets deserialized back into a CLR object. Book has an AuthorId property which allows this to happen. But it also has a Author property. Problem, comes when you try to SaveOrUpdate() Book and the author_id in the database gets wiped out because the Author was null when the object gets deserialized. This seems like this would be a common problem. What is the workaround? Also, if you instantiate the Author and it has a Books property. The book you are trying to update is already one of these books (List<Book>). We have also run into the "a different object with the same identifier value was already associated with the session" problems. What is the standard process to update a child over a web service?

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  • In the generic programming/TMP world what exactly is a model / a policy and a "concept" ?

    - by Hassan Syed
    I'd like to know the precise yet succinct definitions of these three concepts in one place. The quality of the answer should depend on the following two points. Show a simple code snippet to show how and what the concept/technique is used for. Be simple enough to understand so that a programmer without any exposure to this area can grasp it. Note: There are probably many correct answers since each concept has many different facets. If there are a lot of good answers I will eventually turn the question into CW and aggregate the answers. -- Post Accept Edit -- Boost has a nice article on generic programming concepts

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