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  • SQL Server problems reading columns with a foreign key

    - by illdev
    I have a weird situation, where simple queries seem to never finish for instance SELECT top 100 ArticleID FROM Article WHERE ProductGroupID=379114 returns immediately SELECT top 1000 ArticleID FROM Article WHERE ProductGroupID=379114 never returns SELECT ArticleID FROM Article WHERE ProductGroupID=379114 never returns SELECT top 1000 ArticleID FROM Article returns immediately By 'returning' I mean 'in query analyzer the green check mark appears and it says "Query executed successfully"'. I sometimes get the rows painted to the grid in qa, but still the query goes on waiting for my client to time out - 'sometimes': SELECT ProductGroupID AS Product23_1_, ArticleID AS ArticleID1_, ArticleID AS ArticleID18_0_, Inventory_Name AS Inventory3_18_0_, Inventory_UnitOfMeasure AS Inventory4_18_0_, BusinessKey AS Business5_18_0_, Name AS Name18_0_, ServesPeople AS ServesPe7_18_0_, InStock AS InStock18_0_, Description AS Descript9_18_0_, Description2 AS Descrip10_18_0_, TechnicalData AS Technic11_18_0_, IsDiscontinued AS IsDisco12_18_0_, Release AS Release18_0_, Classifications AS Classif14_18_0_, DistributorName AS Distrib15_18_0_, DistributorProductCode AS Distrib16_18_0_, Options AS Options18_0_, IsPromoted AS IsPromoted18_0_, IsBulkyFreight AS IsBulky19_18_0_, IsBackOrderOnly AS IsBackO20_18_0_, Price AS Price18_0_, Weight AS Weight18_0_, ProductGroupID AS Product23_18_0_, ConversationID AS Convers24_18_0_, DistributorID AS Distrib25_18_0_, type AS Type18_0_ FROM Article AS articles0_ WHERE (IsDiscontinued = '0') AND (ProductGroupID = 379121) shows this behavior. I have no idea what is going on. Probably select is broken ;) I got a foreign key on ProductGroups ALTER TABLE [dbo].[Article] WITH CHECK ADD CONSTRAINT [FK_ProductGroup_Articles] FOREIGN KEY([ProductGroupID]) REFERENCES [dbo].[ProductGroup] ([ProductGroupID]) GO ALTER TABLE [dbo].[Article] CHECK CONSTRAINT [FK_ProductGroup_Articles] there are some 6000 rows and IsDiscontinued is a bit, not null, but leaving this condition out does not change the outcome. Anyone can tell me how to handle such a situation? More info, anyone? Additional Info: this does not seem to be restricted to this Foreign Key, but all/some referencing this entity.

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  • jboss cache as hibernate 2nd level - cluster node doesn't persist replicated data

    - by Sergey Grashchenko
    I'm trying to build an architecture basically described in user guide http://www.jboss.org/file-access/default/members/jbosscache/freezone/docs/3.2.1.GA/userguide_en/html/cache_loaders.html#d0e3090 (Replicated caches with each cache having its own store.) but having jboss cache configured as hibernate second level cache. I've read manual for several days and played with the settings but could not achieve the result - the data in memory (jboss cache) gets replicated across the hosts, but it's not persisted in the datasource/database of the target (not original) cluster host. I had a hope that a node might become persistent at eviction, so I've got a cache listener and attached it to @NoveEvicted event. I found that though I could adjust eviction policy to fully control it, no any persistence takes place. Then I had a though that I could try to modify CacheLoader to set "passivate" to true, but I found that in my case (hibernate 2nd level cache) I don't have a way to access a loader. I wonder if replicated data persistence is possible at all by configuration tuning ? If not, will it work for me to create some manual peristence in CacheListener (I could check whether the eviction event is local, and if not - persist it to hibernate datasource somehow) ? I've used mvcc-entity configuration with the modification of cacheMode - set to REPL_ASYNC. I've also played with the eviction policy configuration. Last thing to mention is that I've tested entty persistence and replication in project that has been generated with Seam. I guess it's not important though.

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  • How to create XSD schema from XML with this kind of structure (in .net)?

    - by Mr. Brownstone
    Here's the problem: my input is XML file that looks something like: <BaseEntityClassInfo> <item> <key>BaseEntityClassInfo.SomeField</key> <value>valueData1</value> </item> <item> <key>BaseEntityClassInfo.AdditionalDataClass.SomeOtherField</key> <value>valueData2</value> </item> <item> <key>BaseEntityClassInfo.AdditionalDataClass.AnotherClassInfo.DisplayedText</key> <value>valueData3</value> </item> ... ... </BaseEntityClassInfo> The <key> element somehow describes entity classes fields and relationships (used in some other app that I don't have access to) and the <value> stores the actual data that I need. My goal is to programatically generate a typed Dataset from this XML that could then be used for creating reports. I thought of building some XSD schema from input XML file first and then use this schema to generate Dataset but I'm not sure how to do that. The problem is that I don't want all data in one table, I need several tables with relationships based on the <key> value so I guess I need to infer relational structure from XML <key> data in some way. So what do you think? How could this be done and what would be the best approach? Any advice, ideas, suggestions would be appreciated!

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  • Preventing HTML character entities in locale files from getting munged by Rails3 xss protection

    - by Chris S
    We're building an app, our first using Rails 3, and we're having to build I18n in from the outset. Being perfectionists, we want real typography to be used in our views: dashes, curled quotes, ellipses et al. This means in our locales/xx.yml files we have two choices: Use real UTF-8 characters inline. Should work, but hard to type, and scares me due to the amount of software which still does naughty things to unicode. Use HTML character entities (&#8217; &#8212; etc). Easier to type, and probably more compatible with misbehaving software. I'd rather take the second option, however the auto-escaping in Rails 3 makes this problematic, as the ampersands in the YAML get auto-converted into character entities themselves, resulting in 'visible' &8217;s in the browser. Obviously this can be worked around by using raw on strings, i.e.: raw t('views.signup.organisation_details') But we're not happy going down the route of globally raw-ing every time we t something as it leaves us open to making an error and producing an XSS hole. We could selectively raw strings which we know contain character entities, but this would be hard to scale, and just feels wrong - besides, a string which contains an entity in one language may not in another. Any suggestions on a clever rails-y way to fix this? Or are we doomed to crap typography, xss holes, hours of wasted effort or all thre?

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  • How to handle image/gif type response on client side using GWT

    - by user200340
    Hi all, I have a question about how to handle image/gif type response on client side, any suggestion will be great. There is a service which responds for retrieving image (only one each time at the moment) from database. The code is something like, JDBC Connection Construct MYSQL query. Execute query If has ResultSet, retrieve first one { //save image into Blob image, “img” is the only entity in the image table. image = rs.getBlob("img"); } response.setContentType("image/gif"); //set response type InputStream in = image.getBinaryStream(); //output Blob image to InputStream int bufferSize = 1024; //buffer size byte[] buffer = new byte[bufferSize]; //initial buffer int length =0; //read length data from inputstream and store into buffer while ((length = in.read(buffer)) != -1) { out.write(buffer, 0, length); //write into ServletOutputStream } in.close(); out.flush(); //write out The code on client side .... imgform.setAction(GWT.getModuleBaseURL() + "serviceexample/ImgRetrieve"); .... ClickListener { OnClick, then imgform.submit(); } formHandler { onSubmit, form validation onSubmitComplete ??????? //handle response, and display image **Here is my question, i had tried Image img = new Image(GWT.getHostPageBaseURL() +"serviceexample/ImgRetrieve"); mg.setSize("300", "300"); imgpanel.add(img); but i only got a non-displayed image with 300X300 size.** } So, how should i handle the responde in this case? Thanks,

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  • how do i implement / build / create an 'in memory database' for my unit test

    - by Michel
    Hi all, i've started unit testing a while ago and as turned out i did more regression testing than unit testing because i also included my database layer thus going to the database verytime. So, implemented Unity to inject a fake database layer, but i of course want to store some data, and the main opinion was: "create an in-memory database" But what is that / how do i implement that? Main question is: i think i have to fake the database layer, but doesn't that make me create a 'simple database' myself or: how can i keep it simple and not rebuilding Sql Server just for my unit tests :) At the end of this question i'll give an explanation of the situation i got in on the project i just started on, and i was wondering if this was the way to go. Michel Current situation i've seen at this client is that testdata is contained in XML files, and there is a 'fake' database layer that connects all the xml files together. For the real database we're using the entity framework, and this works very simple. And now, in the 'fake' layer, i have top create all kind of classes to load, save, persist etc. the data. It sounds weird that there is so much work in the fake layer, and so little in the real layer. I hope this all makes sense :)

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  • Pass Linq Expression to a function

    - by Kushan Hasithe Fernando
    I want to pass a property list of a class to a function. with in the function based on property list I'm going to generate a query. As exactly same functionality in Linq Select method. Here I'm gonna implement this for Ingress Database. As an example, in front end I wanna run a select as this, My Entity Class is like this public class Customer { [System.Data.Linq.Mapping.ColumnAttribute(Name="Id",IsPrimaryKey=true)] public string Id { get; set; } [System.Data.Linq.Mapping.ColumnAttribute(Name = "Name")] public string Name { get; set; } [System.Data.Linq.Mapping.ColumnAttribute(Name = "Address")] public string Address { get; set; } [System.Data.Linq.Mapping.ColumnAttribute(Name = "Email")] public string Email { get; set; } [System.Data.Linq.Mapping.ColumnAttribute(Name = "Mobile")] public string Mobile { get; set; } } I wanna call a Select function like this, var result = dataAccessService.Select<Customer>(C=>C.Name,C.Address); then,using result I can get the Name and Address properties' values. I think my Select function should looks like this, ( *I think this should done using Linq Expression. But im not sure what are the input parameter and return type. * ) Class DataAccessService { // I'm not sure about this return type and input types, generic types. public TResult Select<TSource,TResult>(Expression<Func<TSource,TResult>> selector) { // Here using the property list, // I can get the ColumnAttribute name value and I can generate a select query. } } This is a attempt to create a functionality like in Linq. But im not an expert in Linq Expressions. There is a project call DbLinq from MIT, but its a big project and still i couldn't grab anything helpful from that. Can someone please help me to start this, or can someone link me some useful resources to read about this.

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  • Best way to determine variable type and treat each one differently in F#

    - by James Black
    I have a function that will create a select where clause, but right now everything has to be a string. I would like to look at the variable passed in and determine what type it is and then treat it properly. For example, numeric values don't have single quotes around them, option type will either be null or have some value and boolean will actually be zero or one. member self.BuildSelectWhereQuery (oldUser:'a) = let properties = List.zip oldUser.ToSqlValuesList sqlColumnList let init = false, new StringBuilder() let anyChange, (formatted:StringBuilder) = properties |> Seq.fold (fun (anyChange, sb) (oldVal, name) -> match(anyChange) with | true -> true, sb.AppendFormat(" AND {0} = '{1}'", name, oldVal) | _ -> true, sb.AppendFormat("{0} = '{1}'", name, oldVal) ) init formatted.ToString() Here is one entity: type CityType() = inherit BaseType() let mutable name = "" let mutable stateId = 0 member this.Name with get() = name and set restnameval=name <- restnameval member this.StateId with get() = stateId and set stateidval=stateId <- stateidval override this.ToSqlValuesList = [this.Name; this.StateId.ToString()] So, if name was some other value besides a string, or stateId can be optional, then I have two changes to make: How do I modify ToSqlValuesList to have the variable so I can tell the variable type? How do I change my select function to handle this? I am thinking that I need a new function does the processing, but what is the best FP way to do this, rather than using something like typeof?

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  • NHibernate's ISQLQuery returns instances that are of an unexpected type.

    - by Frederik Gheysels
    Hi all, I'm using NHibernate 2.1.2.400, and I'm having an issue with a an ISQLQuery query. The reason why I use an ISQLQuery here, is that this query uses a table for which I have no entity mapped in NHibernate. The query looks like this: ISQLQuery query = session.CreateSQLQuery ( "select p.*, price.* " + "from prestation p left outer join prestationprice price on p.PrestationId = price.PrestationId " + "where p.Id IN ( select id from prestationregistry where ..."); 'Prestationregistry' is the table that is not known by NHibernate (unmapped, so therefore the native SQL Query). my code continues like this: query.AddEntity ("p", typeof(Prestation)); query.AddJoin ("price", typeof(PrestationPrice)); query.SetResultTransformer (Transformers.DistinctRootEntity); var result = query.List(); So far so good. I expect that I'm given a list of 'Prestation' instances as a result of this query, since I declared 'Prestation' as being the root-object that has to be returned by the AddEntity method. I also expect that the PrestationPrices for each Prestation are eagerly loaded by this query (hence the AddJoin method). To my surprise, the List() method returns a collection of PrestationPrice instances instead of Prestation instances. How come ? Am I doing something wrong ? And if so, could you be so kind to tell me what I'm doing wrong ? Edit: Additional Info: When I debug, and put a watch on the 'query' instance, I can see that the queryReturns member of the query contains 2 items: - one NativeSqlQueryRootReturn instance who'se ReturnEntityName is 'Prestation' - one NativeSqlQueryJoinReturn When I do not specify the 'DistinctRootEntity' result transformer, the query returns instances of 'Prestation' instead of PrestationPrice. However, it contains multiple copies of the same instance.

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  • What is the corrrect way to increment a field making up part of a composit key

    - by Tr1stan
    I have a bunch of tables whose primary key is made up of the foreign keys of other tables (Composite key). Therefore for example the attributes (as a very cut down version) might look like this: A[aPK, SomeFields] 1:M B[bPK, aFK, SomeFields] 1:M C[cPK, bFK, aFK, SomeFields] as data this could look like: A[aPK, SomeFields]: 1, Foo 2, Bar B[bPK, aFK, SomeFields]: 1, 1, FooData1 2, 1, FooData2 1, 2, BarData1 2, 2, BarData2 C[cPK, bFK, aFK, SomeFields]: 1, 1, 1, FooData1More 2, 1, 1, FooData1More 1, 2, 1, FooData2More 2, 2, 1, FooData2More 1, 1, 2, BarData1More 2, 1, 2, BarData1More 1, 2, 2, BarData2More 2, 2, 2, BarData2More I've got this running in a MSSQL DBMS and I'm looking for the best way to increment the left most column, in each table when a new tuple is added to it. I can't use the Auto Increment Identity Specification option as that has no idea that it is part of a composite key. I also don't want to use any aggregate function such as: MAX(field)+1 as this will have adverse affects with multiple users inputting data, rolling back etc. There might however be a nice trigger based option here, but I'm not sure. This must be a common issue so I'm hoping that someone has a lovely solution. As a side which may or may not affect the answer, I'm using Entity Framework 1.0 as my ORM, within a c# MVC application.

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  • Populate asp.net MVC Index page with data from the database

    - by Sunil Ramu
    I have a web application in which I need to fetch data from the database and display in the index page. As you know, asp.net mvc has given options to edit delete etc... I need to populate the page using the conventional DB way and it uses a stored procedure to retrieve results. I dont want to use LINQ. This is my model entity class using System; using System.Collections.Generic; using System.Linq; using System.Web; namespace LogMVCApp.Models { public class Property { public int Id { get; set; } public string LogInId { get; set; } public string Username { get; set; } public string Action { get; set; } public string Information { get; set; } public bool Passed{get; set; } public string LogType { get; set; } } } and I need to retrieve data using something like this... var conString = ConfigurationManager.ConnectionStrings["connection"].ToString(); var conn = new SqlConnection(conString); var command = new SqlCommand("LogInsert", conn){CommandType=CommandType.StoredProcedure};

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  • Exception handling in Spring MVC with 3 layer architecture

    - by Chorochrondochor
    I am building a simple web applications with 3 layers - DAO, Service, MVC. When in my Controller I want to delete menu group and it contains menus I am getting ConstraintViolationException. Where should I handle this exception? In DAO, Service, or in Controller? Currently I am handling the exception in Controller. My code below. DAO method for deleting menu groups: @Override public void delete(E e){ if (e == null){ throw new DaoException("Entity can't be null."); } getCurrentSession().delete(e); } Service method for deleting menu groups: @Override @Transactional(readOnly = false) public void delete(MenuGroupEntity menuGroupEntity) { menuGroupDao.delete(menuGroupEntity); } Controller method for deleting menu groups in Controller: @RequestMapping(value = "/{menuGroupId}/delete", method = RequestMethod.GET) public ModelAndView delete(@PathVariable Long menuGroupId, RedirectAttributes redirectAttributes){ MenuGroupEntity menuGroupEntity = menuGroupService.find(menuGroupId); if (menuGroupEntity != null){ try { menuGroupService.delete(menuGroupEntity); redirectAttributes.addFlashAttribute("flashMessage", "admin.menu-group-deleted"); redirectAttributes.addFlashAttribute("flashMessageType", "success"); } catch (Exception e){ redirectAttributes.addFlashAttribute("flashMessage", "admin.menu-group-could-not-be-deleted"); redirectAttributes.addFlashAttribute("flashMessageType", "danger"); } } return new ModelAndView("redirect:/admin/menu-group"); }

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  • Tab bar application with UINavigation Controller MOC not being retained.

    - by iamsmug
    I created a tab bar application from the template and added a navigation controller to one of the tabs. I have already created this app from the navigation app template already and is working. The reason I am doing it this way is because I need to add a tab bar and thought it would be easier starting by using the tab bar project template and adding the nav controller to it rather than the other way round. I have copied the data model over from the other project and added the relevant code to where it should be. The problem I am having is passing the moc from the app delegate to the tab with the nav controller on. Here is a snippet from my applicationDidFinishLaunching method in my app delegate: - (void)applicationDidFinishLaunching:(UIApplication *)application { [self createEditableCopyOfDatabaseIfNeeded]; Top_BananaTableViewController *top_BananaTableViewController = (Top_BananaTableViewController *)[navigationController topViewController]; top_BananaTableViewController.managedObjectContext = self.managedObjectContext; // Add the tab bar controller's current view as a subview of the window [window addSubview:tabBarController.view]; [window makeKeyAndVisible]; } Everything seems fine here but when it comes to the fetchedResultsController on my nav controller view it bombs out with: '+entityForName: could not locate an NSManagedObjectModel for entity name 'cards'' When I checked what was set to my managedObjectContext on that view it was null. I don't know why or where it is loosing it's setting. Please help.

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  • Linq generic Expression in query on "element" or on IQueryable (multiple use)

    - by Bogdan Maxim
    Hi, I have the following expression public static Expression<Func<T, bool>> JoinByDateCheck<T>(T entity, DateTime dateToCheck) where T : IDateInterval { return (entityToJoin) => entityToJoin.FromDate.Date <= dateToCheck.Date && (entityToJoin.ToDate == null || entityToJoin.ToDate.Value.Date >= dateToCheck.Date); } IDateInterval interface is defined like this: interface IDateInterval { DateTime FromDate {get;} DateTime? ToDate {get;} } and i need to apply it in a few ways: (1) Query on Linq2Sql Table: var q1 = from e in intervalTable where FunctionThatCallsJoinByDateCheck(e, constantDateTime) select e; or something like this: intervalTable.Where(FunctionThatCallsJoinByDateCheck(e, constantDateTime)) (2) I need to use it in some table joins (as linq2sql doesn't provide comparative join): var q2 = from e1 in t1 join e2 in t2 on e1.FK == e2.PK where OtherFunctionThatCallsJoinByDateCheck(e2, e1.FromDate) or var q2 = from e1 in t1 from e2 in t2 where e1.FK == e2.PK && OtherFunctionThatCallsJoinByDateCheck(e2, e1.FromDate) (3) I need to use it in some queries like this: var q3 = from e in intervalTable.FilterFunctionThatCallsJoinByDateCheck(constantDate); Dynamic linq is not something that I can use, so I have to stick to plain linq. Thank you Clarification: Initially I had just the last method (FilterFunctionThatCallsJoinByDateCheck(this IQueryable<IDateInterval> entities, DateTime dateConstant) ) that contained the code from the expression. The problem is that I get a SQL Translate exception if I write the code in a method and call it like that. All I want is to extend the use of this function to the where clause (see the second query in point 2)

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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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  • Interesting LinqToSql behaviour

    - by Ben Robinson
    We have a database table that stores the location of some wave files plus related meta data. There is a foreign key (employeeid) on the table that links to an employee table. However not all wav files relate to an employee, for these records employeeid is null. We are using LinqToSQl to access the database, the query to pull out all non employee related wav file records is as follows: var results = from Wavs in db.WaveFiles where Wavs.employeeid == null; Except this returns no records, despite the fact that there are records where employeeid is null. On profiling sql server i discovered the reason no records are returned is because LinqToSQl is turning it into SQL that looks very much like: SELECT Field1, Field2 //etc FROM WaveFiles WHERE 1=0 Obviously this returns no rows. However if I go into the DBML designer and remove the association and save. All of a sudden the exact same LINQ query turns into SELECT Field1, Field2 //etc FROM WaveFiles WHERE EmployeeID IS NULL I.e. if there is an association then LinqToSql assumes that all records have a value for the foreign key (even though it is nullable and the property appears as a nullable int on the WaveFile entity) and as such deliverately constructs a where clause that will return no records. Does anyone know if there is a way to keep the association in LinqToSQL but stop this behaviour. A workaround i can think of quickly is to have a calculated field called IsSystemFile and set it to 1 if employeeid is null and 0 otherwise. However this seems like a bit of a hack to work around strange behaviour of LinqToSQl and i would rather do something in the DBML file or define something on the foreign key constraint that will prevent this behaviour.

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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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  • A good data model for finding a user's favorite stories

    - by wings
    Original Design Here's how I originally had my Models set up: class UserData(db.Model): user = db.UserProperty() favorites = db.ListProperty(db.Key) # list of story keys # ... class Story(db.Model): title = db.StringProperty() # ... On every page that displayed a story I would query UserData for the current user: user_data = UserData.all().filter('user =' users.get_current_user()).get() story_is_favorited = (story in user_data.favorites) New Design After watching this talk: Google I/O 2009 - Scalable, Complex Apps on App Engine, I wondered if I could set things up more efficiently. class FavoriteIndex(db.Model): favorited_by = db.StringListProperty() The Story Model is the same, but I got rid of the UserData Model. Each instance of the new FavoriteIndex Model has a Story instance as a parent. And each FavoriteIndex stores a list of user id's in it's favorited_by property. If I want to find all of the stories that have been favorited by a certain user: index_keys = FavoriteIndex.all(keys_only=True).filter('favorited_by =', users.get_current_user().user_id()) story_keys = [k.parent() for k in index_keys] stories = db.get(story_keys) This approach avoids the serialization/deserialization that's otherwise associated with the ListProperty. Efficiency vs Simplicity I'm not sure how efficient the new design is, especially after a user decides to favorite 300 stories, but here's why I like it: A favorited story is associated with a user, not with her user data On a page where I display a story, it's pretty easy to ask the story if it's been favorited (without calling up a separate entity filled with user data). fav_index = FavoriteIndex.all().ancestor(story).get() fav_of_current_user = users.get_current_user().user_id() in fav_index.favorited_by It's also easy to get a list of all the users who have favorited a story (using the method in #2) Is there an easier way? Please help. How is this kind of thing normally done?

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  • Hibernate does not allow an embedded object with an int field to be null?

    - by Jason Novak
    Hibernate does not allow me to persist an object that contains an null embedded object with an integer field. For example, if I have a class called Thing that looks like this @Entity public class Thing { @Id public String id; public Part part; } where Part is an embeddable class that looks like this @Embeddable public class Part { public String a; public int b; } then trying to persist a Thing object with a null Part causes Hibernate to throw an Exception. In particular, this code Thing th = new Thing(); th.id = "thing.1"; th.part = null; session.saveOrUpdate(th); causes Hibernate to throw this Exception org.hibernate.PropertyValueException: not-null property references a null or transient value: com.ace.moab.api.jobs.Thing.part My guess is that this is happening because Part is an embedded class and so Part.a and Part.b are simply columns in the Thing database table. Since the Thing.part is null Hibernate wants to set the Part.a and Part.b column values to null for the row for thing.1. However, Part.b is an integer and Hibernate will not allow integer columns in the database to be null. This is what causes the Exception, right? So I am looking for workarounds for this problem. I noticed making Part.b an Integer instead of an int seems to work, but for reasons I won't bore you with this is not a good option for us. Thanks!

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  • How to provide an inline model field with a queryset choices without losing field value for inline r

    - by Judith Boonstra
    The code displayed below is providing the choices I need for the app field, and the choices I need for the attr field when using Admin. I am having a problem with the attr field on the inline form for already saved records. The attr selected for these saved does show in small print above the field, but not within the field itself. # MODELS: Class Vocab(models.Model): entity = models.Charfield, max_length = 40, unique = True) Class App(models.Model): name = models.ForeignKey(Vocab, related_name = 'vocab_appname', unique = True) app = SelfForeignKey('self, verbose_name = 'parent', blank = True, null = True) attr = models.ManyToManyField(Vocab, related_name = 'vocab_appattr', through ='AppAttr' def parqs(self): a method that provides a queryset consisting of available apps from vocab, excluding self and any apps within the current app's dependent line. def attrqs(self): a method that provides a queryset consisting of available attr from vocab excluding those already selected by current app, 2) those already selected by any apps within the current app's parent line, and 3) those selected by any apps within the current app's dependent line. Class AppAttr(models.Model): app = models.ForeignKey(App) attr = models.ForeignKey(Vocab) # FORMS: from models import AppAttr def appattr_form_callback(instance, field, *args, **kwargs) if field.name = 'attr': if instance: return field.formfield(queryset = instance.attrqs(), *kwargs) return field.formfield(*kwargs) # ADMIN: necessary imports class AppAttrInline(admin.TabularInline): model = AppAttr def get_formset(self, request, obj = None, **kwargs): kwargs['formfield_callback'] = curry(appattr_form_callback, obj) return super(AppAttrInline, self).get_formset(request, obj, **kwargs) class AppForm(forms.ModelForm): class Meta: model = App def __init__(self, *args, **kwargs): super(AppForm, self).__init__(*args, **kwargs) if self.instance.id is None: working = App.objects.all() else: thisrec = App.objects.get(id = self.instance.id) working = thisrec.parqs() self.fields['par'].queryset = working class AppAdmin(admin.ModelAdmin): form = AppForm inlines = [AppAttrInline,] fieldsets = .......... necessary register statements

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  • Convert a Dynamic[] construct to a numerical list

    - by Leo Alekseyev
    I have been trying to put together something that allows me to extract points from a ListPlot in order to use them in further computations. My current approach is to select points with a Locator[]. This works fine for displaying points, but I cannot figure out how to extract numerical values from a construct with head Dynamic[]. Below is a self-contained example. By dragging the gray locator, you should be able to select points (indicated by the pink locator and stored in q, a list of two elements). This is the second line below the plot. Now I would like to pass q[[2]] to a function, or perhaps simply display it. However, Mathematica treats q as a single entity with head Dynamic, and thus taking the second part is impossible (hence the error message). Can anyone shed light on how to convert q into a regular list? EuclideanDistanceMod[p1_List, p2_List, fac_: {1, 1}] /; Length[p1] == Length[p2] := Plus @@ (fac.MapThread[Abs[#1 - #2]^2 &, {p1, p2}]) // Sqrt; test1 = {{1.`, 6.340196001221532`}, {1.`, 13.78779876355869`}, {1.045`, 6.2634018978377295`}, {1.045`, 13.754947081416544`}, {1.09`, 6.178367702583522`}, {1.09`, 13.72055251752498`}, {1.135`, 1.8183153704413153`}, {1.135`, 6.082497198000075`}, {1.135`, 13.684582525399742`}, {1.18`, 1.6809452373465104`}, {1.18`, 5.971583107298081`}, {1.18`, 13.646996905469383`}, {1.225`, 1.9480537697339537`}, {1.225`, 5.838386922625636`}, {1.225`, 13.607746407088161`}, {1.27`, 2.1183174369679234`}, {1.27`, 5.669799095595362`}, {1.27`, 13.566771130126131`}, {1.315`, 2.2572975468163463`}, {1.315`, 5.444014254828522`}, {1.315`, 13.523998701347882`}, {1.36`, 2.380307009155079`}, {1.36`, 5.153024664297602`}, {1.36`, 13.479342200528283`}, {1.405`, 2.4941312539733285`}, {1.405`, 4.861423833512566`}, {1.405`, 13.432697814928654`}, {1.45`, 2.6028066447609426`}, {1.45`, 4.619367407525507`}, {1.45`, 13.383942212133244`}}; DynamicModule[{p = {1.2, 10}, q = {1.3, 11}}, q := Dynamic@ First@test1[[ Ordering[{#, EuclideanDistanceMod[p, #, {1, .1}]} & /@ test1, 1, #1[[2]] < #2[[2]] &]]]; Grid[{{Show[{ListPlot[test1, Frame -> True, ImageSize -> 300], Graphics@Locator[Dynamic[p]], Graphics@ Locator[q, Appearance -> {Small}, Background -> Pink]}]}, {Dynamic@p}, {q},{q[[2]]}}]]

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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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  • What is the best way to return result from business layer to presentation layer when using linq - I

    - by samsur
    I have a business layer that has DTOs that are used in the presentation layer. This application uses entity framework. Here is an example of a class called RoleDTO public class RoleDTO { public Guid RoleId { get; set; } public string RoleName { get; set; } public string RoleDescription { get; set; } public int? OrganizationId { get; set; } } In the BLL I want to have a method that returns a list of DTO.. I would like to know which is the better approach: returning IQueryable or list of DTOs. Although i feel that returning Iqueryable is not a good idea because the connection needs to be open. Here are the 2 different methods using the different approaches public class RoleBLL { private servicedeskEntities sde; public RoleBLL() { sde = new servicedeskEntities(); } public IQueryable<RoleDTO> GetAllRoles() { IQueryable<RoleDTO> role = from r in sde.Roles select new RoleDTO() { RoleId = r.RoleID, RoleName = r.RoleName, RoleDescription = r.RoleDescription, OrganizationId = r.OrganizationId }; return role; } Note: in the above method the datacontext is a private attribute and set in the constructor, so that the connection stays opened. Second approach public static List GetAllRoles() { List roleDTO = new List(); using (servicedeskEntities sde = new servicedeskEntities()) { var roles = from pri in sde.Roles select new { pri.RoleID, pri.RoleName, pri.RoleDescription }; //Add the role entites to the DTO list and return. This is necessary as anonymous types can be returned acrosss methods foreach (var item in roles) { RoleDTO roleItem = new RoleDTO(); roleItem.RoleId = item.RoleID; roleItem.RoleDescription = item.RoleDescription; roleItem.RoleName = item.RoleName; roleDTO.Add(roleItem); } return roleDTO; } Please let me know, if there is a better approach - Thanks,

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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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  • XSLT: insert parameter value inside of an html attribute

    - by usr
    How to make the following code insert the youtubeId parameter: <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE xsl:stylesheet [ <!ENTITY nbsp "&#x00A0;"> ]> <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:msxml="urn:schemas-microsoft-com:xslt" xmlns:YouTube="urn:YouTube" xmlns:umbraco.library="urn:umbraco.library" exclude-result-prefixes="msxml umbraco.library YouTube"> <xsl:output method="xml" omit-xml-declaration="yes"/> <xsl:param name="videoId"/> <xsl:template match="/"> <a href="{$videoId}">{$videoId}</a> <object width="425" height="355"> <param name="movie" value="http://www.youtube.com/v/{$videoId}&amp;hl=en"></param> <param name="wmode" value="transparent"></param> <embed src="http://www.youtube.com/v/{$videoId}&amp;hl=en" type="application/x-shockwave-flash" wmode="transparent" width="425" height="355"></embed> </object>$videoId {$videoId} {$videoId} <xsl:value-of select="/macro/videoId" /> </xsl:template> </xsl:stylesheet> As you can see I have experimented quite a bit. <xsl:value-of select="/macro/videoId" /> actually outputs the videoId but all other occurences do not. This must be an easy question to answer but I just cannot get it to work.

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