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• Database schema for Product Properties

  - by Chemosh

  As so many people I'm looking for a Products /Product Properties database schema. I'm using Ruby on Rails and (Thinking) Sphinx for faceted searches. Requirements: Adding new product types and their options should not require a change to the database schema Support faceted searches using Sphinx. Solutions I've come across: (See Bill Karwin's answer) Option 1: Single Table Inheritance Not an option really. The table would contain way to many columns. Option 2: Class Table Inheritance Ruby on Rails caches the database schema on start-up which means a restart whenever a new type of product is introduced. If you have a size able product catalog this could mean hundreds of tables. Option 3: Serialized LOB Kills being able to do faceted searches without heavy application logic. Option 4: Entity-Attribute-Value For testing purposes, EAV worked fine. However it could quickly become a mess and a maintenance hell as you add more and more options (e.g. when an option increase the prices or delivery time). What option should I go with? What other solutions are out there? Is there a silver bullet (ha) I overlooked?

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• NHibernate + Fluent long startup time

  - by PaRa

  Hi all, am new to NHibernate. When performing below test took 11.2 seconds (debug mode) i am seeing this large startup time in all my tests (basically creating the first session takes a tone of time) setup = Windows 2003 SP2 / Oracle10gR2 latest CPU / ODP.net 2.111.7.20 / FNH 1.0.0.636 / NHibernate 2.1.2.4000 / NUnit 2.5.2.9222 / VS2008 SP1 using System; using System.Collections; using System.Data; using System.Globalization; using System.IO; using System.Text; using System.Data; using NUnit.Framework; using System.Collections.Generic; using System.Data.Common; using NHibernate; using log4net.Config; using System.Configuration; using FluentNHibernate; [Test()] public void GetEmailById() { Email result; using (EmailRepository repository = new EmailRepository()) { results = repository.GetById(1111); } Assert.IsTrue(results != null); } public class EmailRepository : RepositoryBase { public EmailRepository():base() { } } In my RepositoryBase public T GetById(object id) { using (var session = sessionFactory.OpenSession()) using (var transaction = session.BeginTransaction()) { try { T returnVal = session.Get(id); transaction.Commit(); return returnVal; } catch (HibernateException ex) { // Logging here transaction.Rollback(); return null; } } } The query time is very small. The resulting entity is really small. Subsequent queries are fine. Its seems to be getting the first session started. Has anyone else seen something similar?

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• Moving from NHibernate to FluentNHibernate: assembly error (related to versions)?

  - by goober

  Not sure where to start, but I had gotten the most recent version of NHibernate, successfully mapped the most simple of business objects, etc. When trying to move to FluentNHibernate and do the same thing, I got this error message on build: "System.IO.FileLoadException: Could not load file or assembly 'NHibernate, Version=2.1.0.4000, Culture=neutral, PublicKeyToken=aa95f207798dfdb4' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference." Background: I'm new to Hibernate, NHibernate, and FluentNHibernate -- but not to .NET, C#, etc. Database I have a database table called Category: (PK) CategoryID (type: int), unique, auto-incrementing UserID (type: uniqueidentifier) -- given the value of the user Guid in ASP.NET database Title (type: varchar(50) -- the title of the category Components involved: I have a SessionProviderClass which creates the mapping to the database I have a Category class which has all the virtual methods for FluentNHibernate to override I have a CategoryMap : ClassMap class, which does the fluent mappings for the entity I have a CategoryRepository class that contains the method to add & save the category I have the TestCatAdd.aspx file which uses the CategoryRepository class. Would be happy to post code for any of those, but I'm not sure that it's necessary, as I think the issue is that somewhere there's a version conflict between what FluentNHibernate references and the NHibernate I have installed from before. Thanks in advance for any help you can give!

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• .NET 3.5 DataGridView Wont Save To Database

  - by Jimbo

  I have created a test Winforms application in Visual Studio 2008 (SP1) to see just how "RAD" C# and .NET 3.5 can be. So far I have mixed emotions. Added a service-based database to my application (MyDB.mdf) and added two tables - Contact (id [identity], name [varchar] and number [varchar] columns) and Group (id [identity] and name [varchar] columns) Added a DataSource, selected "Database" as the source, used the default connection string as the connection (which points to my database) and selected "All Tables" to be included in the data source and saved as MyDBDataSet Expanded the data source showing my two tables, selected the "Group" table and chose to display it as a DataGridView (from the dropdown option on the right of each entity) and dragged it onto Form1, thus creating a groupBindingNavigator, groupBindingSource, groupTableAdapter, tableAdapterManager, myDBDataset and groupDataGridView Press F5 to test the application, enter the name "Test" under the DataGridView's "name" column and click "Save" on the navigator which has autogenerated code to save the data that looks like this: private void groupBindingNavigatorSaveItem_Click(object sender, EventArgs e) { this.Validate(); this.groupBindingSource.EndEdit(); this.tableAdapterManager.UpdateAll(this.myDBDataSet); } Stop the application and have a look at the database data, you will see no data saved there in the "Group" table. I dont know why and cant find out how to fix it! Googled for about 30 minutes with no luck. The code is auto-generated with the controls, so you'd think that it would work too :)

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• C# + Querying XML with LINQ

  - by user336786

  Hello, I'm learning to use LINQ. I have seen some videos online that have really impressed me. In an effort to learn LINQ myself, I decided to try to write a query to the NOAA web service. If you put "http://www.weather.gov/forecasts/xml/sample_products/browser_interface/ndfdBrowserClientByDay.php?zipCodeList=20001&format=24+hourly&startDate=2010-06-10&numDays=5" in your browser's address bar, you will see some XML. I have successfully retrieved that XML in a C# program. I am loading the XML into a LINQable entity by doing the following: string xml = QueryWeatherService(); XDocument weather = XDocument.Parse(xml); I have a class called DailyForecast defined as follows: public class DailyForecast { public float HighTemperature { get; set; } public float LowTemperature { get; set; } public float PrecipitationPossibility { get; set; } public string WeatherSummary { get; set; } } I'm trying write a LINQ query that adheres to the structure of my DailyForecast class. At this time, I've only gotten to this far: var results = from day in response.Descendants("parameters") select day; Not very far I know. Because of the structure of the XML returned, I'm not sure it is possible to solely use a LINQ query. I think the only way to do this is via a loop and traverse the XML. I'm seeking someone to correct me if I'm wrong. Can someone please tell me if I can get results using purely LINQ that adhere to the structure of the DailyForecast class? If so, how? Thank you!

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• DDD: Enum like entities

  - by Chris

  Hi all, I have the following DB model: **Person table** ID | Name | StateId ------------------------------ 1 Joe 1 2 Peter 1 3 John 2 **State table** ID | Desc ------------------------------ 1 Working 2 Vacation and domain model would be (simplified): public class Person { public int Id { get; } public string Name { get; set; } public State State { get; set; } } public class State { private int id; public string Name { get; set; } } The state might be used in the domain logic e.g.: if(person.State == State.Working) // some logic So from my understanding, the State acts like a value object which is used for domain logic checks. But it also needs to be present in the DB model to represent a clean ERM. So state might be extended to: public class State { private int id; public string Name { get; set; } public static State New {get {return new State([hardCodedIdHere?], [hardCodeNameHere?]);}} } But using this approach the name of the state would be hardcoded into the domain. Do you know what I mean? Is there a standard approach for such a thing? From my point of view what I am trying to do is using an object (which is persisted from the ERM design perspective) as a sort of value object within my domain. What do you think? Question update: Probably my question wasn't clear enough. What I need to know is, how I would use an entity (like the State example) that is stored in a database within my domain logic. To avoid things like: if(person.State.Id == State.Working.Id) // some logic or if(person.State.Id == WORKING_ID) // some logic

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• Update/Insert without select

  - by user348731

  I have this very simple class public class ProductAttributeValuePortal { public virtual int ID { get; set; } public virtual Domain.Entity.Portals.ProductPortal Product { get; set; } public virtual Attribute Attribute { get; set; } public virtual string Value { get; set; } } with this very simple map public ProductAttributeValueMap () { Table("DM.dbo.ProductAttributeValues"); Id(x => x.ID, "ProductAttributeValue_id"); References(x => x.Product); References(x => x.Attribute); Map(x => x.Value); } Each time i make a insert NHibernate makes a Select of the attribute like : NHibernate: INSERT INTO MachineData.dbo.ProductAttributeValues (Value, Product_id, Attribute_id) VALUES (@p0, @p1, @p2); select SCOPE_IDENTITY();@p0 = '6745', @p1 = 39, @p2 = 'BSTD' NHibernate: SELECT attribute_.Attribute_id, attribute_.Name as Name21_, attribute_.AttributeType as Attribut3_21_, attribute_.TagName as TagName21_, attribute_.MapTo as MapTo21_ FROM MachineShared.dbo.Attributes attribute_ WHERE attribute_.Attribute_id=@p0;@p0 = 'DLB' What am i doing wrong. And where do i find some really uptodate books about nhibernate/Fluent nhibernate

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• Save and Load Dictionary from encrypted or unreadable or binary format ?

  - by Prix

  I have a dictionary like the follow: public Dictionary<int, SpawnList> spawnEntities = new Dictionary<int, SpawnList>(); The class being used is as follow: public class SpawnList { public int NpcID { get; set; } public string Name { get; set; } public int Level { get; set; } public int TitleID { get; set; } public int StaticID { get; set; } public entityType Status { get; set; } public int TypeA { get; set; } public int TypeB { get; set; } public int TypeC { get; set; } public int ZoneID { get; set; } public int Heading { get; set; } public float PosX { get; set; } public float PosY { get; set; } public float PosZ { get; set; } } /// <summary>Entity type enum.</summary> public enum entityType { Ally, Enemy, SummonPet, NPC, Object, Monster, Gatherable, Unknown } How could I save this Dictionary to either a binary or encrypted format so I could later Load it again into my application ? My limitation is .Net 3.5 can't use anything higher.

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• Altering ManagedObjects In NSArray

  - by Garry

  I have an entity called 'Job' with two boolean attributes named 'completed' and 'logged'. I am trying to retrieve all completed jobs that have not been logged at app start-up and change them to logged. I'm able to get all the completed but unlogged jobs with this fetchRequest: NSPredicate *predicate = [NSPredicate predicateWithFormat:@"(completed == %@ && logged == %@)", [NSNumber numberWithBool:YES], [NSNumber numberWithBool:NO]]; I'm then assigning this predicate to a fetchRequest and calling the [managedObjectContext executeFetchRequest:fetchRequest] method to get an array of all Job entities that meet this criteria. This seems to work fine and is returning the correct number of jobs. What I've been trying to do is loop through the NSArray returned, set the logged attribute to YES and then save. This seems to complete and doesn't return any errors but the changes are not persisted when the application quits. Where am I going wrong? [fetchRequest setPredicate:predicate]; NSError error; NSArray jobsToLog = [managedObjectContext executeFetchRequest:fetchRequest error:&error]; if ([jobsToLog count] > 0) { for (int i = 0; i < [jobsToLog count] - 1; i++) { [[jobsToLog objectAtIndex:i] setLogged:[NSNumber numberWithBool:YES]]; // Commit the changes made to disk error = nil; if (![managedObjectContext save:&error]) { // An error occurred } } } Thanks in anticipation,

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• C++ Namespaces & templates question

  - by Kotti

  Hi! I have some functions that can be grouped together, but don't belong to some object / entity and therefore can't be treated as methods. So, basically in this situation I would create a new namespace and put the definitions in a header file, the implementation in cpp file. Also (if needed) I would create an anonymous namespace in that cpp file and put all additional functions that don't have to be exposed / included to my namespace's interface there. See the code below (probably not the best example and could be done better with another program architecture, but I just can't think of a better sample...) Sample code (header) namespace algorithm { void HandleCollision(Object* object1, Object* object2); } Sample code (cpp) #include "header" // Anonymous namespace that wraps // routines that are used inside 'algorithm' methods // but don't have to be exposed namespace { void RefractObject(Object* object1) { // Do something with that object // (...) } } namespace algorithm { void HandleCollision(Object* object1, Object* object2) { if (...) RefractObject(object1); } } So far so good. I guess this is a good way to manage my code, but I don't know what should I do if I have some template-based functions and want to do basically the same. If I'm using templates, I have to put all my code in the header file. Ok, but how should I conceal some implementation details then? Like, I want to hide RefractObject function from my interface, but I can't simply remove it's declaration (just because I have all my code in a header file)... The only approach I came up with was something like: Sample code (header) namespace algorithm { // Is still exposed as a part of interface! namespace impl { template <typename T> void RefractObject(T* object1) { // Do something with that object // (...) } } template <typename T, typename Y> void HandleCollision(T* object1, Y* object2) { impl::RefractObject(object1); // Another stuff } } Any ideas how to make this better in terms of code designing?

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• How to create custom query for CollectionOfElements

  - by Shervin

  Hi. I have problems creating a custom query. This is what entities: @Entity public class ApplicationProcess { @CollectionOfElements private Set<Template> defaultTemplates; //more fields } And Template.java @Embeddable @EqualsAndHashCode(exclude={"file", "selected", "used"}) public class Template implements Comparable<Template> { @Setter private ApplicationProcess applicationProcess; @Setter private Boolean used = Boolean.valueOf(false); public Template() { } @Parent public ApplicationProcess getApplicationProcess() { return applicationProcess; } @Column(nullable = false) @NotNull public String getName() { return name; } @Column(nullable = true) public Boolean isUsed() { return used; } public int compareTo(Template o) { return getName().compareTo(o.getName()); } } I want to create a update statement. I have tried these two: int v = entityManager.createQuery("update ApplicationProcess_defaultTemplates t set t.used = true " + "WHERE t.applicationProcess.id=:apId").setParameter("apId", ap.getId()) .executeUpdate(); ApplicationProcess_defaultTemplates is not mapped [update ApplicationProcess_defaultTemplates t set t.used = true WHERE t.applicationProcess.id=:apId] And I have tried int v = entityManager.createQuery("update Template t set t.used = true " + "WHERE t.applicationProcess.id=:apId").setParameter("apId", ap.getId()) .executeUpdate(); With the same error: Template is not mapped [update Template t set t.used = true WHERE t.applicationProcess.id=:apId] Any ideas? UPDATE I fixed it by creating native query int v = entityManager.createNativeQuery("update ApplicationProcess_defaultTemplates t set t.used=true where t.ApplicationProcess_id=:apId").setParameter("apId", ap.getId()).executeUpdate();

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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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• Table not created by Hibernate

  - by User1

  I annotated a bunch of POJO's so JPA can use them to create tables in Hibernate. It appears that all of the tables are created except one very central table called "Revision". The Revision class has an @Entity(name="RevisionT") annotation so it will be renamed to RevisionT so there is not a conflict with any reserved words in MySQL (the target database). I delete the entire database, recreate it and basically open and close a JPA session. All the tables seem to get recreated without a problem. Why would a single table be missing from the created schema? What instrumentation can be used to see what Hibernate is producing and which errors? Thanks. UPDATE: I tried to create as a Derby DB and it was successful. However, one of the fields has a a name of "index". I use @org.hibernate.annotations.IndexColumn to specify the name to something other than a reserved word. However, the column is always called "index" when it is created. Here's a sample of the suspect annotations. @ManyToOne @JoinColumn(name="MasterTopID") @IndexColumn(name="Cx3tHApe") protected MasterTop masterTop; Instead of creating MasterTop.Cx3tHApe as a field, it creates MasterTop.Index. Why is the name ignored?

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• NHibernate. Initiate save collection at saving parent

  - by Andrew Kalashnikov

  Hello, colleagues. I've got a problem at saving my entity. MApping: ?xml version="1.0" encoding="utf-8" ?> <hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" assembly="Clients.Core" namespace="Clients.Core.Domains"> <class name="Sales, Clients.Core" table='sales'> <id name="Id" unsaved-value="0"> <column name="id" not-null="true"/> <generator class="native"/> </id> <property name="Guid"> <column name="guid"/> </property> <set name="Accounts" table="sales_users" lazy="false"> <key column="sales_id" /> <element column="user_id" type="Int32" /> </set> Domain: public class Sales : BaseDomain { ICollection<int> accounts = new List<int>(); public virtual ICollection<int> Accounts { get { return accounts; } set { accounts = value; } } public Sales() { } } When I save Sales object Account collection don't save at sales_users table. What should I do for saving it? Please don't advice me use classes inside List Thanks a lot.

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• Compare values in serialized column in Doctrine with Query Builder

  - by ReynierPM

  I'm building a FormType for a Symfony2 project but I need some Query Builder on the field since I need to compare some values with the one stored on DB and show the results. This is what I have: .... ->add('servicio', 'entity', array( 'mapped' => false, 'class' => 'ComunBundle:TipoServicio', 'property' => 'nombre', 'required' => true, 'label' => false, 'expanded' => true, 'multiple' => true, 'query_builder' => function (EntityRepository $er) { return $er->createQueryBuilder('ts') ->where('ts.tipo_usuario = (:tipo)') ->setParameter('tipo', 1); } )) .... But tipo_usuario at DB table is stored as serialized text for example: record1: value1 | a:1:{i:0;s:1:"1";} record2: value2 | a:4:{i:0;s:1:"1";i:1;s:1:"2";i:2;s:1:"3";i:3;s:1:"4";} I'll have two different forms (I don't know how to pass the Request to a form) in the first one I'll only show the first record and for the second one the first and second record for example: First form will show: checkbox: value1 Second form will show: checkbox: value1 checkbox: value2 I achieve this? Any help?

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• What is the difference between .get() and .fetch(1)

  - by AutomatedTester

  I have written an app and part of it is uses a URL parser to get certain data in a ReST type manner. So if you put /foo/bar as the path it will find all the bar items and if you put /foo it will return all items below foo So my app has a query like data = Paths.all().filter('path =', self.request.path).get() Which works brilliantly. Now I want to send this to the UI using templates {% for datum in data %} <div class="content"> <h2>{{ datum.title }}</h2> {{ datum.content }} </div> {% endfor %} When I do this I get data is not iterable error. So I updated the Django to {% for datum in data.all %} which now appears to pull more data than I was giving it somehow. It shows all data in the datastore which is not ideal. So I removed the .all from the Django and changed the datastore query to data = Paths.all().filter('path =', self.request.path).fetch(1) which now works as I intended. In the documentation it says The db.get() function fetches an entity from the datastore for a Key (or list of Keys). So my question is why can I iterate over a query when it returns with fetch() but can't with get(). Where has my understanding gone wrong?

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• NHibernate.MappingException on table insertion.

  - by Suja

  The table structure is : The controller action to insert a row to table is public bool CreateInstnParts(string data) { IDictionary myInstnParts = DeserializeData(data); try { HSInstructionPart objInstnPartBO = new HSInstructionPart(); using (ISession session = Document.OpenSession()) { using (ITransaction transaction = session.BeginTransaction()) { objInstnPartBO.DocumentId = Convert.ToInt32(myInstnParts["documentId"]); objInstnPartBO.InstructionId = Convert.ToInt32(myInstnParts["instructionId"]); objInstnPartBO.PartListId = Convert.ToInt32(myInstnParts["part"]); objInstnPartBO.PartQuantity = Convert.ToInt32(myInstnParts["quantity"]); objInstnPartBO.IncPick = Convert.ToBoolean(myInstnParts["incpick"]); objInstnPartBO.IsTracked = Convert.ToBoolean(myInstnParts["istracked"]); objInstnPartBO.UpdatedBy = User.Identity.Name; objInstnPartBO.UpdatedAt = DateTime.Now; session.Save(objInstnPartBO); transaction.Commit(); } return true; } } catch (Exception ex) { Console.Write(ex.Message); return false; } } This is throwing an exception NHibernate.MappingException was caught Message="No persister for: Hexsolve.Data.BusinessObjects.HSInstructionPart" Source="NHibernate" StackTrace: at NHibernate.Impl.SessionFactoryImpl.GetEntityPersister(String entityName) at NHibernate.Impl.SessionImpl.GetEntityPersister(String entityName, Object obj) at NHibernate.Event.Default.AbstractSaveEventListener.SaveWithGeneratedId(Object entity, String entityName, Object anything, IEventSource source, Boolean requiresImmediateIdAccess) at NHibernate.Event.Default.DefaultSaveOrUpdateEventListener.SaveWithGeneratedOrRequestedId(SaveOrUpdateEvent event) at NHibernate.Event.Default.DefaultSaveEventListener.SaveWithGeneratedOrRequestedId(SaveOrUpdateEvent event) at NHibernate.Event.Default.DefaultSaveOrUpdateEventListener.EntityIsTransient(SaveOrUpdateEvent event) at NHibernate.Event.Default.DefaultSaveEventListener.PerformSaveOrUpdate(SaveOrUpdateEvent event) at NHibernate.Event.Default.DefaultSaveOrUpdateEventListener.OnSaveOrUpdate(SaveOrUpdateEvent event) at NHibernate.Impl.SessionImpl.FireSave(SaveOrUpdateEvent event) at NHibernate.Impl.SessionImpl.Save(Object obj) at HexsolveMVC.Controllers.InstructionController.CreateInstnParts(String data) in F:\Project\HexsolveMVC\Controllers\InstructionController.cs:line 1342 InnerException: Can anyone help me solve this??

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• Strategies for dealing with Circular references caused by JPA relationships?

  - by ams

  I am trying to partition my application into modules by features packaged into separate jars such as feature-a.jar, feature-b.jar, ... etc. Individual feature jars such as feature-a.jar should contain all the code for a feature a including jpa entities, business logic, rest apis, unit tests, integration test ... etc. The problem I am running into is that bi-directional relationships between JPA entities cause circular references between the jar files. For example Customer entity should be in customer.jar and the Order should be in order.jar but Customer references order and order references customer making it hard to split them into separate jars / eclipse projects. Options I see for dealing with the circular dependencies in JPA entities: Option 1: Put all the entities into one jar / one project Option 2: Don't map certain bi-directianl relationships to avoid circular dependencies across projects. Questions: What rules / principles have you used to decide when to do bi-directional mapping vs. not? Have you been able to break jpa entities into their own projects / jar by features if so how did you avoid the circular dependencies issues?

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• Why ASP.NET menu control ignores roles in Web.sitemap?

  - by MainMa

  Hi, I have a website with a menu based on sitemap. ActiveDirectoryRoleProvider is a custom class. securityTrimmingEnabled of sitemap provider is set to true. Now, nevertheless the roles set in the sitemap file, site menu displays every sitemap entity. So for example if I have in sitemap a node with roles="*", a second one with roles="Administrators" and a third one with roles="Foo" and I login as a member of Administrators group but not Foo group, the site menu will display all three items. On the other hand, if I have a node which does not specify roles attribute but has children, this node will never be displayed. If I put: <%= HttpContext.Current.User.IsInRole("Administrators") ? "Admin" : "Not admin"%> <%= HttpContext.Current.User.IsInRole("Foo") ? "Foo" : "Not foo"%> before the menu, it displays that I'm Admin, but Not foo, which is just fine. So if it knows that I'm Admin but Not foo, why does it continue to display Foo's sitemap nodes? Note: changing authorizations has no effect on the menu. It continues to show every item, even for the pages I'm unable to access.

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• Can I make an identity field span multiple tables in SQL Server?

  - by johnnycakes

  Can I have an "identity" (unique, non-repeating) column span multiple tables? For example, let's say I have two tables: Books and Authors. Authors AuthorID AuthorName Books BookID BookTitle The BookID column and the AuthorID column are identity columns. I want the identity part to span both columns. So, if there is an AuthorID with a value of 123, then there cannot be a BookID with a value of 123. And vice versa. I hope that makes sense. Is this possible? Thanks. Why do I want to do this? I am writing an APS.NET MVC app. I am creating a comment section. Authors can have comments. Books can have comments. I want to be able to pass an entity ID (a book ID or an author ID) to an action and have the action pull up all the corresponding comments. The action won't care if it's a book or an author or whatever. Sound reasonable?

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• Linq to SQL - Failing to update

  - by Isaac

  Hello, I'm having some troubles with updating linq to sql entities. For some reason, I can update every single field of my item entity besides name. Here are two simple tests I wrote: [TestMethod] public void TestUpdateName( ) { using ( var context = new SimoneDataContext( ) ) { Item item = context.Items.First( ); if ( item != null ) { item.Name = "My New Name"; context.SubmitChanges( ); } } } [TestMethod] public void TestUpdateMPN( ) { using ( var context = new SimoneDataContext( ) ) { Item item = context.Items.First( ); if ( item != null ) { item.MPN = "My New MPN"; context.SubmitChanges( ); } } } Unfortunately, TestUpdateName() fails with the following error: System.Data.SqlClient.SqlException: Incorrect syntax near the keyword 'WHERE'.. And here's the outputted SQL: UPDATE [dbo].[Items] SET WHERE ([Id] = @p0) AND ([CategoryId] = @p1) AND ([MPN] = @p2) AND ([Height] = @p3) AND ([Width] = @p4) AND ([Weight] = @p5) AND ([Length] = @p6) AND ([AdministrativeCost] = @p7) -- @p0: Input Int (Size = 0; Prec = 0; Scale = 0) [1] -- @p1: Input Int (Size = 0; Prec = 0; Scale = 0) [1] -- @p2: Input VarChar (Size = 10; Prec = 0; Scale = 0) [My New MPN] -- @p3: Input Decimal (Size = 0; Prec = 5; Scale = 3) [30.000] -- @p4: Input Decimal (Size = 0; Prec = 5; Scale = 3) [10.000] -- @p5: Input Decimal (Size = 0; Prec = 5; Scale = 3) [40.000] -- @p6: Input Decimal (Size = 0; Prec = 5; Scale = 3) [30.000] -- @p7: Input Money (Size = 0; Prec = 19; Scale = 4) [350.0000] -- Context: SqlProvider(Sql2008) Model: AttributedMetaModel Build: 3.5.30729.4926 As you can see, no update is being generated (SET is empty ...) I have no clue why is this happening. And already in advance ... YES, the table Item has a PK (Id). Thank you in advance!

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• Python + Expat: Error on &#0; entities

  - by clacke

  I have written a small function, which uses ElementTree and xpath to extract the text contents of certain elements in an xml file: #!/usr/bin/env python2.5 import doctest from xml.etree import ElementTree from StringIO import StringIO def parse_xml_etree(sin, xpath): """ Takes as input a stream containing XML and an XPath expression. Applies the XPath expression to the XML and returns a generator yielding the text contents of each element returned. >>> parse_xml_etree( ... StringIO('<test><elem1>one</elem1><elem2>two</elem2></test>'), ... '//elem1').next() 'one' >>> parse_xml_etree( ... StringIO('<test><elem1>one</elem1><elem2>two</elem2></test>'), ... '//elem2').next() 'two' >>> parse_xml_etree( ... StringIO('<test><null>&#0;</null><elem3>three</elem3></test>'), ... '//elem2').next() 'three' """ tree = ElementTree.parse(sin) for element in tree.findall(xpath): yield element.text if __name__ == '__main__': doctest.testmod(verbose=True) The third test fails with the following exception: ExpatError: reference to invalid character number: line 1, column 13 Is the � entity illegal XML? Regardless whether it is or not, the files I want to parse contain it, and I need some way to parse them. Any suggestions for another parser than Expat, or settings for Expat, that would allow me to do that?

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• (Rails) Creating multi-dimensional hashes/arrays from a data set...?

  - by humble_coder

  Hi All, I'm having a bit of an issue wrapping my head around something. I'm currently using a hacked version of Gruff in order to accommodate "Scatter Plots". That said, the data is entered in the form of: g.data("Person1",[12,32,34,55,23],[323,43,23,43,22]) ...where the first item is the ENTITY, the second item is X-COORDs, and the third item is Y-COORDs. I currently have a recordset of items from a table with the columns: POINT, VALUE, TIMESTAMP. Due to the "complex" calculations involved I must grab everything using a single query or risk way too much DB activity. That said, I have a list of items for which I need to dynamically collect all data from the recordset into a hash (or array of arrays) for the creation of the data items. I was thinking something like the following: @h={} e = Events.find_by_sql(my_query) e.each do |event| @h["#{event.Point}"][x] = event.timestamp @h["#{event.Point}"][y] = event.value end Obviously that's not the correct syntax, but that's where my brain is going. Could someone clean this up for me or suggest a more appropriate mechanism by which to accomplish this? Basically the main goal is to keep data for each pointname grouped (but remember the recordset has them all). Much appreciated. EDIT 1 g = Gruff::Scatter.new("600x350") g.title = self.name e = Event.find_by_sql(@sql) h ={} e.each do |event| h[event.Point.to_s] ||= {} h[event.Point.to_s].merge!({event.Timestamp.to_i,event.Value}) end h.each do |p| logger.info p[1].values.inspect g.data(p[0],p[1].keys,p[1].values) end g.write(@chart_file)

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• Asp.net mvc inheritance controllers

  - by Ris90

  Hi, I'm studing asp.net mvc and in my test project I have some problems with inheritance: In my model I use inheritanse in few entities: public class Employee:Entity { /* few public properties */ } It is the base class. And descendants: public class RecruitmentOfficeEmployee: Employee { public virtual RecruitmentOffice AssignedOnRecruitmentOffice { get; set; } } public class ResearchInstituteEmployee: Employee { public virtual ResearchInstitute AssignedOnResearchInstitute { get; set; } } I want to implement a simple CRUD operations to every descedant. What is the better way to inplement controllers and views in descendants: - One controller per every descendant; - Controller inheritance; - Generic controller; - Generic methods in one controller. Or maybe there is an another way? My ORM is NHibernate, I have a generic base repository and every repository is its descedant. Using generic controller, I think, is the best way, but in it I will use only generic base repository and extensibility of the system will be not very good. Please, help the newbie)

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• Hibernate Transient Extends problem

  - by mrvreddy

  @MappedSuperclass public abstract class BaseAbstract implements Serializable{ private static final long serialVersionUID = 1L; protected String test = //some random value; public String getTest() { return test; } public void setTest(String test){ this.test = test; } } @Entity public class Artist extends BaseAbstract { private static final long serialVersionUID = 1L; private Integer id; @override @Transient public String getTest() { return test; } ..... } My question is... when i am trying to do any operation on the artist, along with id and name, test is also getting saved which should not be the case... if i add the same transient on the baseabstract class getTest() method, i see test column NOT getting created(ideally what it should happen) but if i try to override the method with adding annotaion in the sub class it creates the test column... I dont know why this is happening since when hibernate is creating the artist object and checks for annotations, it should see the transient annotation present on the getTest() of artist method...and should not create a column in the database... Let me know if you need any clarification.... Any response on this is greatly appreciated.... Thank you

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