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• Re-sizing the form without scaling the GUI

  - by Bmoore

  I am writing a turn based strategy game in C#. My GUI implementation consists of class that extends Form containing a class that extends Panel. When I render the GUI I draw to the paint method in the panel. I am trying to figure out what is the best way for handling form re-size events. I know I want a minimum window size, but I would prefer to not have a maximum or a set size. Ideally the GUI would reveal more/less of the map as the user changes the window size. I would like to avoid scaling the graphics if at all possible. What is the best way to handle re-size events?

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• Should I implement an interface directly or have the superclass do it?

  - by c_maker

  Is there a difference between public class A extends AbstractB implements C {...} versus... public class A extends AbstractB {...} AbstractB implements C {...} I understand that in both cases, class A will end up conforming to the interface. In the second case, AbstractB can provide implementation for interface methods in C. Is that the only difference? If I do NOT want to provide an implementation for any of the interface methods in AbstractB, which style should I be using? Does using one or the other have some hidden 'documentation' purpose?

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• Why does DirectX use a left-handed coordinate system?

  - by greyfade

  I considered posting on Stack Overflow, but the question strikes me as being far too subjective since I can't think of a reasonable technical explanation for Microsoft's choice in this matter. But this question has bugged me for so long and the issue keeps coming up in one of my projects, and I have never actually seen an attempt at explaining this: OpenGL uses a right-handed coordinate system, where the +Z part of the world coordinate system extends toward the viewer. DirectX uses a left-handed system where the +Z part of the world coordinate extends into the screen, away from the viewer. I never used the Glide API, so I don't know how it worked, but from what I can gather, it uses a left-handed system as well. Is there a technical reason for this? And if not, is there some conceptual advantage to a particular handedness of a coordinate system? Why would one choose one over the other?

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• Sharing object between 2 classes

  - by Justin

  I am struggling to wrap my head around being able to share an object between two classes. I want to be able to create only one instance of the object, commonlib in my main class and then have the classes, foo1 and foo2, to be able to mutually share the properties of the commonlib. commonlib is a 3rd party class which has a property Queries that will be added to in each child class of bar. This is why it is vital that only one instance is created. I create two separate queries in foo1 and foo2. This is my setup: abstract class bar{ //common methods } class foo1 extends bar{ //add query to commonlib } class foo2 extends bar{ //add query to commonlib } class main { public $commonlib = new commonlib(); public function start(){ //goal is to share one instance of $this->commonlib between foo1 and foo2 //so that they can both add to the properites of $this->commonlib (global //between the two) //now execute all of the queries after foo1 and foo2 add their query $this->commonlib->RunQueries(); } }

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• Interface hierarchy design for separate domains

  - by jerzi

  There are businesses and people. People could be liked and businesses could be commented on: class Like class Comment class Person implements iLikeTarget class Business implements iCommentTarget Likes and comments are performed by a user(person) so they are authored: class Like implements iAuthored class Comment implements iAuthored People's like could also be used in their history: class history class Like implements iAuthored, iHistoryTarget Now, a smart developer comes and says each history is attached to a user so history should be authored: interface iHistoryTarget extends iAuthored so it could be removed from class Like: class Person implements iLikeTarget class Business implements iCommentTarget class Like implements iHistoryTarget class Comment implements iAuthored class history interface iHistoryTarget extends iAuthored Here, another smart guy comes with a question: How could I capture the Authored fact in Like and Comment classes? He may knows nothing about history concept in the project. By scalling these kind of functionallities, interfaces may goes to their encapsulated types which cause more type strength, on the other hand explicitness suffered and also code end users will face much pain to process. So here is the question: Should I encapsulate those dependant types to their parent types (interface hierarchies) or not or explicitly repeat each type for every single level of my type system or ...?

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• How to access functions in extended classes efficiently?

  - by nischayn22

  In PHP I have classes as below class Animal { //some vars public function printname(){ echo $this->name; } } class AnimalMySql extends Animal { static public function getTableFields(){ return array(); } } class AnimalPostgreSql extends Animal { static public function getTableFields(){ return array(); } } Now I have an object $lion = new Animal(); and I want to do if($store == mysql) //getTableFields from class AnimalMySql else //getTableFields form class AnimalPostgreSql I am new to OOP and not sure what is the best way to call the method from the specific class P.S. Please leave a note with the answer to explain the efficiency of the approach

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• Blank lines between sourcecode [closed]

  - by manix

  I'm so confused with a strange behaviour. Actually I have edited some php files remotely with my PhpDesigner8 (a php editor). Everything goes right, but when my teammates reopen the files that I have edited the source code have blank lines like below: class AdminController extends Controller { function __construct() { parent::__construct(); if (!$this->session->can_admin()) { show_error('Solo para administradores.'); } $this->load->library('backend'); } } Instead of class AdminController extends Controller { function __construct() { parent::__construct(); if (!$this->session->can_admin()) { show_error('Solo para administradores.'); } $this->load->library('backend'); } } Did you have experience these kinds of problems?

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• How should dependencies be managed across a modular application?

  - by bear

  Let's say that we have a structure like this: Application -- Modules --Module1 -- Controller -- PublicHelper --Module2 -- Controller -- PublicHelper Whereby a module's Public Helper can provide helper functions. In nearly every module helper, the helper needs to access another module's public helper methods. Let's say for instance, in a PHP application: Module1 provides functionality to create a sale, and as part of the class Module1PublicHelper extends AbstractModuleHelper { public function createSale($customerId, $param, $param) { $userPublicHelper = // grab an instance of the user public helper $currentUser = $userPublicHelper->getCurrentUser(); } } class Module2PublicHelper extends AbstractModuleHelper { public function getCurrentUser() { //do something return $user; } } In this situation, the method needs to obtain an instance, either new or whatever of the user public helper. Given that all of Module Public Helper classes are instantiated with a minimum set of constructor params, e.g. EntityManager, what would be the best way to get a copy of it? Obviously, we can't really inject the user public helper class into the class containing createSale One solution would be to use a service locator or registry, however, testing the application isn't exactly easy.

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• The Mysterious ARR Server Farm to URL Rewrite link

  - by OWScott

  Application Request Routing (ARR) is a reverse proxy plug-in for IIS7+ that does many things, including functioning as a load balancer.  For this post, I’m assuming that you already have an understanding of ARR.  Today I wanted to find out how the mysterious link between ARR and URL Rewrite is maintained.  Let me explain… ARR is unique in that it doesn’t work by itself.  It sits on top of IIS7 and uses URL Rewrite.  As a result, ARR depends on URL Rewrite to ‘catch’ the traffic and redirect it to an ARR Server Farm. As the last step of creating a new Server Farm, ARR will prompt you with the following: If you accept the prompt, it will create a URL Rewrite rule for you.  If you say ‘No’, then you’re on your own to create a URL Rewrite rule. When you say ‘Yes’, the Server Farm’s checkbox for “Use URL Rewrite to inspect incoming requests” will be checked.  See the following screenshot. However, I’m not a fan of this auto-rule.  The problem is that if I make any changes to the URL Rewrite rule, which I always do, and then make the wrong change in ARR, it will blow away my settings.  So, I prefer to create my own rule and manage it myself. Since I had some old rules that were managed by ARR, I wanted to update them so that they were no longer managed that way.  I took a look at a config in applicationHost.config to try to find out what property would bind the two together.  I assumed that there would be a property on the ServerFarm called something like urlRewriteRuleName that would serve as the link between ARR and URL Rewrite.  I found no such property.  After a bit of testing, I found that the name of the URL Rewrite rule is the only link between ARR and URL Rewrite.  I wouldn’t have guessed.  The URL Rewrite rule needs to be exactly ARR_{ServerFarm Name}_loadBalance, although it’s not case sensitive. Consider the following auto-created URL Rewrite rule: And, the link between ARR and URL Rewrite exists: Now, as soon as I rename that to anything else, for example, site.com ARR Binding, the link between ARR and URL Rewrite is broken. To be certain of the relationship, I renamed it back again and sure enough, the relationship was reestablished. Why is this important?  It’s only important if you want to decouple the relationship between ARR the URL Rewrite rule, but if you want to do so, the best way to do that is to rename the URL Rewrite rule.  If you uncheck the “Use URL Rewrite to inspect incoming requests” checkbox, it will delete your rule for you without prompting.  Conclusion The mysterious link between ARR and URL Rewrite only exists through the ARR Rule name.  If you want to break the link, simply rename the URL Rewrite rule.  It’s completely safe to do so, and, in my opinion, this is a rule that you should manage yourself anyway. 

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• Understanding the Customer Form in Release 12 from an AR Perspective!!

  - by user793553

  Confused by the Customer Form in Release 12??  Read on, to get some insight into the evolution of this screen, and how it links in with Trading Community Architecture. Historically, the customer data model was owned by Oracle Receivables (AR).  However, as the data model changed and more complex relationships and attributes had to be tracked and monitored, the Trading Community Architecture (TCA) product was created.  All applications within the E-Business suite that require interaction with a customer integrate with TCA. Customer information is no longer stored in the individual applications but rather in a central repository/registry maintained within TCA.  It is important to understand the following entities/concepts stored in TCA: Party: A party is an entity with whom you can have a potential business relationship.  A party can be either a Person or an Organization.  The Party entity is completely independent of any business relationship; this means that a Party can exist even if you have no transactions with it.   The Party is the "umbrella" entity under which you capture all other attributes listed below. Customer: A customer is a party with whom you have an existing business relationship.  From an AR perspective, you can simplify the concepts by thinking of a Customer as a Party. This definition however does not apply to all other applications. In the Oracle Receivables Customer form, the information displayed at the Customer level is from TCA's Party information record. Customer Account (also called Account): An account contains information about how you transact business with a particular customer.  You can create multiple accounts for a customer.  When you create invoices and receipts you associate it to a particular Account of a Customer. Location: A Location is an address.  It is a point in space, typically identified by a street number, a street name, a city, a state or province, a country.  A location is independent of what it is used for - you do not associate a purpose to a location. Party Site: A Party Site is associated to a Party.  It is the location where a party is physically located.  When defining sites for a Party, only one can be an identifying address.  However, you can define other party sites associated to a party. You can define purposes/usage for Party Sites. Account Site: An Account Site is associated to a Customer Account. It is the location associated to the account you are transacting business with. You can define business purposes (also called site uses) for an Account site. Read more about the Customer Workbench in these notes: Doc ID 1436547.1 Oracle Receivables: Understanding the Customer Form in Release 12 Doc ID  1437866.1 Customer Form - Address: Troubleshooting, Known Issues and Patches Doc ID  1448442.1 Oracle Receivables (AR): Customer Workbench Information Center Do you find this type of blog entry useful?  Please add comments to let us know how we can help you more effectively.  Thank you!

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• Java constructor using generic types

  - by user37903

  I'm having a hard time wrapping my head around Java generic types. Here's a simple piece of code that in my mind should work, but I'm obviously doing something wrong. Eclipse reports this error in BreweryList.java: The method initBreweryFromObject() is undefined for the type <T> The idea is to fill a Vector with instances of objects that are a subclass of the Brewery class, so the invocation would be something like: BreweryList breweryList = new BreweryList(BrewerySubClass.class, list); BreweryList.java package com.beerme.test; import java.util.Vector; public class BreweryList<T extends Brewery> extends Vector<T> { public BreweryList(Class<T> c, Object[] j) { super(); for (int i = 0; i < j.length; i++) { T item = c.newInstance(); // initBreweryFromObject() is an instance method // of Brewery, of which <T> is a subclass (right?) c.initBreweryFromObject(); // "The method initBreweryFromObject() is undefined // for the type <T>" } } } Brewery.java package com.beerme.test; public class Brewery { public Brewery() { super(); } protected void breweryMethod() { } } BrewerySubClass.java package com.beerme.test; public class BrewerySubClass extends Brewery { public BrewerySubClass() { super(); } public void androidMethod() { } } I'm sure this is a complete-generics-noob question, but I'm stuck. Thanks for any tips!

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• Entity Framework: Delete Object and its related entities

  - by Waheed

  Hi, Does anyone know how to delete an object and all of it's related entities. For example i have tables, Products, Category, ProductCategory and productDetails, the productCategory is joining table of both Product and Category. I have red from http://msdn.microsoft.com/en-us/library/bb738580.aspx that Deleting the parent object also deletes all the child objects in the constrained relationship. This result is the same as enabling the CascadeDelete property on the association for the relationship. I am using this code Product productObj = this.ObjectContext.Product.Where(p => p.ProductID.Equals(productID)).First(); if (!productObj.ProductCategory.IsLoaded) productObj.ProductCategory.Load(); if (!productObj.ProductDetails.IsLoaded) productObj.ProductDetails.Load(); //my own methods. base.Delete(productObj); base.SaveAllObjectChanges(); But i am getting error on ObjectContext.SaveChanges(); i.e A relationship is being added or deleted from an AssociationSet 'FK_ProductCategory_Product'. With cardinality constraints, a corresponding 'ProductCategory' must also be added or deleted. Thanks in advance....

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• Is it possible to force the WCF test client to accept a self-signed certificate?

  - by Lawrence Johnston

  I have a WCF web service running in IIS 7 using a self-signed certificate (it's a proof of concept to make sure this is the route I want to go). It's required to use SSL. Is it possible to use the WCF Test Client to debug this service without needing a non-self-signed certificate? When I try I get this error: Error: Cannot obtain Metadata from https:///Service1.svc If this is a Windows (R) Communication Foundation service to which you have access, please check that you have enabled metadata publishing at the specified address. For help enabling metadata publishing, please refer to the MSDN documentation at http://go.microsoft.com/fwlink/?LinkId=65455.WS-Metadata Exchange Error URI: https:///Service1.svc Metadata contains a reference that cannot be resolved: 'https:///Service1.svc'. Could not establish trust relationship for the SSL/TLS secure channel with authority ''. The underlying connection was closed: Could not establish trust relationship for the SSL/TLS secure channel. The remote certificate is invalid according to the validation procedure.HTTP GET Error URI: https:///Service1.svc There was an error downloading 'https:///Service1.svc'. The underlying connection was closed: Could not establish trust relationship for the SSL/TLS secure channel. The remote certificate is invalid according to the validation procedure.

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• SugarCRM SOAP set_relationship between Contacts and Prospect lists bug

  - by AntonioCS

  Hey! I am trying to create a relationship between a Prospect List (target list) and a Contact. I create a new contact and get the id of a prospect list all using classes I created which are just wrappers for the soap api calls sugar provides. But the code boils down to this soap call: $this->_sugarsoap->client->__soapCall('set_relationship', array($this->getSessionid(),$relationship)); $this-getSessionid() Is the session Id and $relationship is an array which holds this: array 0 => string 'ProspectLists' (length=13) 1 => string '180ab1f5-cf7e-d386-50f8-4c18a790e016' (length=36) 2 => string 'Contacts' (length=8) 3 => string '76323942-8cbb-3224-f18a-4c19efa80a1b' (length=36) After I try this I always get this error: (I do a var_dump of the returned values of the soap call) object(stdClass)[5] public 'number' => string '20' (length=2) public 'name' => string 'Module Does Not Exist' (length=21) public 'description' => string 'This module is not available on this server' (length=43) This seems like a sugarcrm bug because I do have the contacts module and also the prospect lists module. I know this for a fact because I add a contact via the soap call and also retrieve the id of a prospect list via the soap call. I found this thread in the sugar forums and I did try the code given there but I still got the same error. Anyone have a solution for this? I really need to associate a contact to a prospect list (target list) via a soap call. I am using SugarCRM 5.5.0 (I also tried with sugarcrm 5.5.2 and got the same error) on ubuntu server using mysql. Thanks!

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• LINQ to SQL: filter nested objects with soft deletes

  - by Alex

  Hello everyone, I'm using soft deleting in my database (IsDeleted field). I'm actively using LoadWith and AssociateWith methods to retrieve and filter nested records. The thing is AssociateWith only works with properties that represents a one-to-many relationship. DataLoadOptions loadOptions = new DataLoadOptions(); loadOption.LoadWith<User>(u = > u.Roles); loadOption.AssociateWith<User>(u = > u.Roles.Where(r = > !r.IsDeleted)); In the example above I just say: I want to retrieve users with related (undeleted) roles. But when I have one-to-one relationship, e.g. Document - File (the only one file is related to the document) I'm unable to filter soft deleted object: DataLoadOptions loadOptions = new DataLoadOptions(); loadOption.LoadWith<Document>(d = > d.File); // the next certainly won't work loadOption.AssociateWith<File>(f = > !f.IsDeleted); So, is there any idea how to filter records within the one-to-one relationship? Thanks!

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• Delete record in Linq to Sql

  - by Anders Svensson

  I have Linq2Sql classes User, Page, and UserPage (from a junction table), i.e. a many-to-many relationship. I'm using a gridview to show all Users, with a dropdownlist in each row to show the Pages visited by each user. Now I want to be able to delete records through the gridview, so I have added a delete button in the gridview by setting "Enable deleting" on it. Then I tried to use the RowDeleting event to specify how to delete the records since it doesn't work by default. And because its a relationship I know I need to delete the related records in the junction table before deleting the user record itself, so I added this in the RowDeleting event: protected void GridView2_RowDeleting(object sender, GridViewDeleteEventArgs e) { int id = (int)((DataKey)GridView2.DataKeys[e.RowIndex]).Value; UserPageDBDataContext context = new UserPageDBDataContext(); var userPages = from userPage in context.UserPages where userPage.User.UserID == id select userPage; foreach (var userPage in userPages) context.UserPages.DeleteOnSubmit(userPage); context.SubmitChanges(); var user = context.Users.Single(u => u.UserID == id); context.Users.DeleteOnSubmit(user); context.SubmitChanges(); } This actually seems to delete records, because the record with the id in question does indeed disappear, but strangely, a new record seems to be added at the end...! So, say I have 3 records in the gridview: 1 Jack stackoverflow.com 2 Betty stackoverflow.com/questions 3 Joe stackoverflow.com/whatever Now, if I try to delete user 1 (Jack), record number 1 will indeed disappear in the gridview, but the same record will appear at the end with a new id: 2 Jack stackoverflow.com 3 Betty stackoverflow.com/questions 4 Joe stackoverflow.com/whatever I have tried searching on how to delete records using Linq, and I believe I'm doing exacly as the examples I have read (e.g. the second example here: http://msdn.microsoft.com/en-us/library/Bb386925%28v=VS.100%29.aspx). I have read that you can also set cascade delete on the relationship in the database, but I wanted to do it this way in code, as your supposed to be able to. So what am I doing wrong?

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• edmx - The operation could not be completed - After adding Inheritance

  - by vdh_ant

  Hey guys I have an edmx model which I have draged 2 tables onto - One called 'File' and the other 'ApplicaitonFile'. These two tables have a 1 to 1 relationship in the database. If I stop here everything works fine. But in my model, I want 'ApplicaitonFile' to inherit from 'File'. So I delete the 1 to 1 relationship then configure 'ApplicaitonFile' from 'File' and then remove the FileId from 'ApplicaitonFile' which was the primary key. (Note I am following the instructions from here). If I leave the model open at this point everything is fine, but as soon as I close it, if I try and reopen it again I get the following error "The operation could not be completed". I have been searching for a solution and found this - http://stackoverflow.com/questions/944050/entity-model-does-not-load but as far as I can tell I don't have a duplicate InheritanceConnectors (although I don't know exactly what I'm looking for but I can't see anything out of the ordinary - like 2 connectors with the same name) and the relationship I originally have is a 1 to 1 not a 1 to 0..1 Any ideas???

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• Entity Framework Update Error in ASP.NET Mvc with related entity

  - by Barry

  I have run into a problem which have searched and tried everything i can to find a solution but to no avail. I am using the same repository and context throughout the process I have a booking entity and a userExtension Entity Below is my image i then get my form collection back from my page and create a new booking public ActionResult Create(FormCollection collection) { Booking toBooking = new Booking(); i then do some validation and property assignment and find an associated BidInstance toBooking.BidInstance = bid; i have checked and the bid is not null. finally i get the user extension file from the Current IPRINCIPAL USER as below UserExtension loggedInUser = m_BookingRepository.GetBookingCurrentUser(User); toBooking.UserExtension = loggedInUser; The Code to do the getUserExtension is : public UserExtension GetBookingCurrentUser(IPrincipal currentUser) { var user = (from u in Context.aspnet_Users .Include("UserExtension") where u.UserName == currentUser.Identity.Name select u).FirstOrDefault(); if (user != null) { var userextension = (from u in Context.UserExtension.Include("aspnet_Users") where u.aspnet_Users.UserId == user.UserId select u).FirstOrDefault(); return userextension; } else{ return null; } } It returns the userextension fine and assigns it fine. i originally used the aspnet_users but encountered this problem so tried to change it to the extension entity. as soon as i call the : Context.AddToBooking(booking); Context.SaveChanges(); i get the following exception and im completely baffled by how to fix it Entities in 'FutureFlyersEntityModel.Booking' participate in the 'FK_Booking_UserExtension' relationship. 0 related 'UserExtension' were found. 1 'UserExtension' is expected. then the final error that comes to the front end is: Metadata information for the relationship 'FutureFlyersModel.FK_Booking_BidInstance' could not be retrieved. Make sure that the EdmRelationshipAttribute for the relationship has been defined in the assembly. Parameter name: relationshipName.. But both the related entities are set in the booking entity passed thruogh PLEASE HELP Im at wits end with this

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• USE case to Class Diagram - How do I?

  - by 01010011

  Hi, I would like your guidance on how to create classes and their relationships (generalization, association, aggregation and composition) accurately from my USE case diagram (please see below). I am trying to create this class diagram so I can use it to create a simple online PHP application that allows the user to register an account, login and logout, and store, search and retrieve data from a MySQL database. Are my classes correct? Or should I create more classes? And if so, what classes are missing? What relationships should I use when connecting the register, login, logout, search_database and add_to_database to the users? I'm new to design patterns and UML class diagrams but from my understanding, the association relationship relates one object with another object; the aggregation relationship is a special kind of association that allows "a part" to belong to more than one "whole" (e.g. a credit card and its PIN - the PIN class can also be used in a debit card class); and a composition relationship is a special form of aggregation that allows each part to belong to only one whole at a time. I feel like I have left out some classes or something because I just can't seem to find the relationships from my understanding of relationships. Any assistance will be really appreciated. Thanks in advance. USE CASE DIAGRAM CLASS DIAGRAM

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• Building a many-to-many db schema using only an unpredictable number of foreign keys

  - by user1449855

  Good afternoon (at least around here), I have a many-to-many relationship schema that I'm having trouble building. The main problem is that I'm only working with primary and foreign keys (no varchars or enums to simplify things) and the number of many-to-many relationships is not predictable and can increase at any time. I looked around at various questions and couldn't find something that directly addressed this issue. I split the problem in half, so I now have two one-to-many schemas. One is solved but the other is giving me fits. Let's assume table FOO is a standard, boring table that has a simple primary key. It's the one in the one-to-many relationship. Table BAR can relate to multiple keys of FOO. The number of related keys is not known beforehand. An example: From a query FOO returns ids 3, 4, 5. BAR needs a unique key that relates to 3, 4, 5 (though there could be any number of ids returned) The usual join table does not work: Table FOO_BAR primary_key | foo_id | bar_id | Since FOO returns 3 unique keys and here bar_id has a one-to-one relationship with foo_id. Having two join tables does not seem to work either, as it still can't map foo_ids 3, 4, 5 to a single bar_id. Table FOO_TO_BAR primary_key | foo_id | bar_to_foo_id | Table BAR_TO_FOO primary_key | foo_to_bar_id | bar_id | What am I doing wrong? Am I making things more complicated than they are? How should I approach the problem? Thanks a lot for the help.

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• Modeling multiple polymorphic relationships using Hibernate

  - by f-potter

  Ruby on Rails has polymorphic relations which are really useful for implementing functionality such as commenting, tagging and rating to name a few. We can have a comment, tag or rating class which has a many to one polymorphic relationship with a commentable, taggable and rateable object. Also, a given domain object can choose to implement any combination of such relations. So, it can for example be commentable, taggable and rateable at the same time. I couldn't think up of a straightforward way to duplicate this functionality in Hibernate. Ideally, there would be a Comment class which will have a many to one relationship with a Commentable class and a Commentable class will conversely have a one to many relationship with Comments. It will be ideal if the concrete domain classes can inherit from a number of such classes, say Commentable and Taggable. Things seem a little complicated as a Java class can only extend one other class and some code might end up being duplicated across a number of classes. I wanted to know what are the best practices for modeling such relationships neatly and concisely using Hibernate?

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• Linq is returning too many results when joined

  - by KallDrexx

  In my schema I have two database tables. relationships and relationship_memberships. I am attempting to retrieve all the entries from the relationship table that have a specific member in it, thus having to join it with the relationship_memberships table. I have the following method in my business object: public IList<DBMappings.relationships> GetRelationshipsByObjectId(int objId) { var results = from r in _context.Repository<DBMappings.relationships>() join m in _context.Repository<DBMappings.relationship_memberships>() on r.rel_id equals m.rel_id where m.obj_id == objId select r; return results.ToList<DBMappings.relationships>(); } _Context is my generic repository using code based on the code outlined here. The problem is I have 3 records in the relationships table, and 3 records in the memberships table, each membership tied to a different relationship. 2 membership records have an obj_id value of 2 and the other is 3. I am trying to retrieve a list of all relationships related to object #2. When this linq runs, _context.Repository<DBMappings.relationships>() returns the correct 3 records and _context.Repository<DBMappings.relationship_memberships>() returns 3 records. However, when the results.ToList() executes, the resulting list has 2 issues: 1) The resulting list contains 6 records, all of type DBMappings.relationships(). Upon further inspection there are 2 for each real relationship record, both are an exact copy of each other. 2) All relationships are returned, even if m.obj_id == 3, even though objId variable is correctly passed in as 2. Can anyone see what's going on because I've spent 2 days looking at this code and I am unable to understand what is wrong. I have joins in other linq queries that seem to be working great, and my unit tests show that they are still working, so I must be doing something wrong with this. It seems like I need an extra pair of eyes on this one :)

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• How to bundle extension methods requiring configuration in a library

  - by Greg

  Hi, I would like to develop a library that I can re-use to add various methods involved in navigating/searching through a graph (nodes/relationships, or if you like vertexs/edges). The generic requirements would be: There are existing classes in the main project that already implement the equivalent of the graph class (which contains the lists of nodes / relationships), node class and relationship class (which links nodes together) - the main project likely already has persistence mechanisms for the info (e.g. these classes might be built using Entity Framework for persistance) Methods would need to be added to each of these 3 classes: (a) graph class - methods like "search all nodes", (b) node class - methods such as "find all children to depth i", c) relationship class - methods like "return relationship type", "get parent node", "get child node". I assume there would be a need to inform the library with the extending methods the class names for the graph/node/relationships table (as different project might use different names). To some extent it would need to be like how a generics collection works (where you pass the classes to the collection so it knows what they are). Need to be a way to inform the library of which node property to use for equality checks perhaps (e.g. if it were a graph of webpages the equality field to use might be the URI path) I'm assuming that using abstract base classes wouldn't really work as this would tie usage down to have to use the same persistence approach, and same class names etc. Whereas really I want to be able to, for a project that has "graph-like" characteristics, the ability to add graph searching/walking methods to it.

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• Using HABTM relationships in cakephp plugins with unique set to false

  - by Dean

  I am working on a plugin for our CakePHP CMS that will handle blogs. When getting to the tags I needed to set the HABTM relationship to unique = false to be able add tags to a post without having to reset them all. The BlogPost model looks like this class BlogPost extends AppModel { var $name = 'BlogPost'; var $actsAs = array('Core.WhoDidIt', 'Containable'); var $hasMany = array('Blog.BlogPostComment'); var $hasAndBelongsToMany = array('Blog.BlogTag' => array('unique' => false), 'Blog.BlogCategory'); } The BlogTag model looks like this class BlogTag extends AppModel { var $name = 'BlogTag'; var $actsAs = array('Containable'); var $hasAndBelongsToMany = array('Blog.BlogPost'); } The SQL error I am getting when I have the unique = true setting in the HABTM relationship between the BlogPost and BlogTag is Query: SELECT `Blog`.`BlogTag`.`id`, `Blog`.`BlogTag`.`name`, `Blog`.`BlogTag`.`slug`, `Blog`.`BlogTag`.`created_by`, `Blog`.`BlogTag`.`modified_by`, `Blog`.`BlogTag`.`created`, `Blog`.`BlogTag`.`modified`, `BlogPostsBlogTag`.`blog_post_id`, `BlogPostsBlogTag`.`blog_tag_id` FROM `blog_tags` AS `Blog`.`BlogTag` JOIN `blog_posts_blog_tags` AS `BlogPostsBlogTag` ON (`BlogPostsBlogTag`.`blog_post_id` = 4 AND `BlogPostsBlogTag`.`blog_tag_id` = `Blog`.`BlogTag`.`id`) As you can see it is trying to set the blog_tags table to 'Blog'.'BlogTag. which isn't a valid MySQL name. When I remove the unique = true from the relationship it all works find and I can save one tag but when adding another it just erases the first one and puts the new one in its place. Does anyone have any ideas? is it a bug or am I just missing something? Cheers, Dean

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• table subtraction challenge

  - by Valentin

  I have a challenge that I haven’t overcome in the last two days using Stored Procedures and SQL 2008. I took several approaches but must fell short. One appraoch very interesting was using a table substraction. It’s really all about table subtraction. I was wondering if you could help me crack this one. Here is the challenge: Two tables 1Testdb y 2Testdb. My first step was to select ID relationships ([2Testdb].Acc_id) on table 2Testdb for one given individual ([2Testdb].Bus_id). Then query table 1Testdb for records not mathcing my original selection from 2Testdb. But other approaches are welcome. Data and Structures: USE [Challengedb] GO SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO CREATE TABLE [dbo].[1Testdb]( [Acc_id] [uniqueidentifier] NULL [Name] [Varchar(10)] NULL ) ON [PRIMARY] GO CREATE TABLE [dbo].[2Testdb]( [Acc_id] [uniqueidentifier] NULL, [Bus_id] [uniqueidentifier] NULL ) ON [PRIMARY] GO Records on 1Testdb: 34455F60-9474-4521-804E-66DB39A579F3, John C23523F6-2309-4F58-BB3F-EF7486C7AF8B, Pete DC711615-3BE4-4B31-9EF2-B1314185CA62, Dave E3AAB073-2398-476D-828B-92829F686A4C, Adam Records on 2Testdb: (Relationship table, ex. Friend relationships) Record #1: DC711615-3BE4-4B31-9EF2-B1314185CA62, 34455F60-9474-4521-804E-66DB39A579F3 Record #2: E3AAB073-2398-476D-828B-92829F686A4C, 34455F60-9474-4521-804E-66DB39A579F3 Record # 3: DC711615-3BE4-4B31-9EF2-B1314185CA62, E3AAB073-2398-476D-828B-92829F686A4C Record # 4: E3AAB073-2398-476D-828B-92829F686A4C, DC711615-3BE4-4B31-9EF2-B1314185CA62 Challenge: Select from table 1Testdb only those records distinct that may not have a relationship with John [34455F60-9474-4521-804E-66DB39A579F3] on table 2Testdb. Expected result should be (Who does John doesn’t have relationship with?): C23523F6-2309-4F58-BB3F-EF7486C7AF8B, Pete Thank you, Valentin

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