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  • EF4 querying from parent to grandchildren

    - by Hans Kesting
    I have a model withs Parents, Children and Grandchildren, in a many-to-many relationship. Using this article I created POCO classes that work fine, except for one thing I can't yet figure out. When I query the Parents or Children directly using LINQ, the SQL reflects the LINQ query (a .Count() executes a COUNT in the database and so on) - fine. The Parent class has a Children property, to access it's children. But (and now for the problem) this doesn't expose an IQueryable interface but an ICollection. So when I access the Children property on a particular parent all the Parent's Children are read. Even worse, when I access the Grandchildren (theParent.Children.SelectMany(child => child.GrandChildren).Count()) then for each and every child a separate request is issued to select all data of it's grandchildren. That's a lot of separate queries! Changing the type of the Children property from ICollection to IQueryable doesn't solve this. Apart from missing methods I need, like Add() and Remove(), EF just doesn't recognize the navigation property then. Are there correct ways (as in: low database interaction) of querying through children (and what are they)? Or is this just not possible?

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  • How can I write a clean Repository without exposing IQueryable to the rest of my application?

    - by Simucal
    So, I've read all the Q&A's here on SO regarding the subject of whether or not to expose IQueryable to the rest of your project or not (see here, and here), and I've ultimately decided that I don't want to expose IQueryable to anything but my Model. Because IQueryable is tied to certain persistence implementations I don't like the idea of locking myself into this. Similarly, I'm not sure how good I feel about classes further down the call chain modifying the actual query that aren't in the repository. So, does anyone have any suggestions for how to write a clean and concise Repository without doing this? One problem I see, is my Repository will blow up from a ton of methods for various things I need to filter my query off of. Having a bunch of: IEnumerable GetProductsSinceDate(DateTime date); IEnumberable GetProductsByName(string name); IEnumberable GetProductsByID(int ID); If I was allowing IQueryable to be passed around I could easily have a generic repository that looked like: public interface IRepository<T> where T : class { T GetById(int id); IQueryable<T> GetAll(); void InsertOnSubmit(T entity); void DeleteOnSubmit(T entity); void SubmitChanges(); } However, if you aren't using IQueryable then methods like GetAll() aren't really practical since lazy evaluation won't be taking place down the line. I don't want to return 10,000 records only to use 10 of them later. What is the answer here? In Conery's MVC Storefront he created another layer called the "Service" layer which received IQueryable results from the respository and was responsible for applying various filters. Is this what I should do, or something similar? Have my repository return IQueryable but restrict access to it by hiding it behind a bunch of filter classes like GetProductByName, which will return a concrete type like IList or IEnumerable?

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  • Custom RoleProvider: Can't insert record in UsersInRole Table

    - by mahr.g.mohyuddin
    Hi, I have implemented a LINQ to SQL based RoleProvider, when I assign role to a user following exception is thrown while AddUsersToRoles method is called. I have defined a composite primary key userid & roleId on this table, it still throwing this exception: Can't perform Create, Update or Delete operations on 'Table(UsersInRole)' because it has no primary key. My LinQ to SQL implementation of AddUsersToRoles method is as follows. It breaks at db.UsersInRoles.InsertOnSubmit(userInRole); using (RussarmsDataContext db = new RussarmsDataContext()) { List<UsersInRole> usersInRole = new List<UsersInRole>(); foreach (string username in usernames) { foreach (string rolename in rolenames) { UsersInRole userInRole = new UsersInRole(); object userId = ProvidersUtility.GetUserIdByUserName(username,applicationName); object roleId = ProvidersUtility.GetRoleIdByRoleName(rolename,applicationName); if (userId != null && roleId != null) { userInRole.UserId = (Guid)userId; userInRole.RoleId = (Guid)roleId; db.UsersInRoles.InsertOnSubmit(userInRole); } } } try { // db.UsersInRoles.InsertAllOnSubmit(usersInRole); db.SubmitChanges(); } catch (ChangeConflictException) { db.ChangeConflicts.ResolveAll(RefreshMode.OverwriteCurrentValues); db.SubmitChanges(); } } Any help will be appreciated. Thanks.

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  • How can I resolve Hibernate 3's ConstraintViolationException when updating a Persistent Entity's Col

    - by Tim Visher
    I'm trying to discover why two nearly identical class sets are behaving different from Hibernate 3's perspective. I'm fairly new to Hibernate in general and I'm hoping I'm missing something fairly obvious about the mappings or timing issues or something along those lines but I spent the whole day yesterday staring at the two sets and any differences that would lead to one being able to be persisted and the other not completely escaped me. I appologize in advance for the length of this question but it all hinges around some pretty specific implementation details. I have the following class mapped with Annotations and managed by Hibernate 3.? (if the specific specific version turns out to be pertinent, I'll figure out what it is). Java version is 1.6. ... @Embeddable public class JobStateChange implements Comparable<JobStateChange> { @Temporal(TemporalType.TIMESTAMP) @Column(nullable = false) private Date date; @Enumerated(EnumType.STRING) @Column(nullable = false, length = JobState.FIELD_LENGTH) private JobState state; @ManyToOne(fetch = FetchType.LAZY) @JoinColumn(name = "acting_user_id", nullable = false) private User actingUser; public JobStateChange() { } @Override public int compareTo(final JobStateChange o) { return this.date.compareTo(o.date); } @Override public boolean equals(final Object obj) { if (this == obj) { return true; } else if (!(obj instanceof JobStateChange)) { return false; } JobStateChange candidate = (JobStateChange) obj; return this.state == candidate.state && this.actingUser.equals(candidate.getUser()) && this.date.equals(candidate.getDate()); } @Override public int hashCode() { return this.state.hashCode() + this.actingUser.hashCode() + this.date.hashCode(); } } It is mapped as a Hibernate CollectionOfElements in the class Job as follows: ... @Entity @Table( name = "job", uniqueConstraints = { @UniqueConstraint( columnNames = { "agency", //Job Name "payment_type", //Job Name "payment_file", //Job Name "date_of_payment", "payment_control_number", "truck_number" }) }) public class Job implements Serializable { private static final long serialVersionUID = -1131729422634638834L; ... @org.hibernate.annotations.CollectionOfElements @JoinTable(name = "job_state", joinColumns = @JoinColumn(name = "job_id")) @Sort(type = SortType.NATURAL) private final SortedSet<JobStateChange> stateChanges = new TreeSet<JobStateChange>(); ... public void advanceState( final User actor, final Date date) { JobState nextState; LOGGER.debug("Current state of {} is {}.", this, this.getCurrentState()); if (null == this.currentState) { nextState = JobState.BEGINNING; } else { if (!this.isAdvanceable()) { throw new IllegalAdvancementException(this.currentState.illegalAdvancementStateMessage); } if (this.currentState.isDivergent()) { nextState = this.currentState.getNextState(this); } else { nextState = this.currentState.getNextState(); } } JobStateChange stateChange = new JobStateChange(nextState, actor, date); this.setCurrentState(stateChange.getState()); this.stateChanges.add(stateChange); LOGGER.debug("Advanced {} to {}", this, this.getCurrentState()); } private void setCurrentState(final JobState jobState) { this.currentState = jobState; } boolean isAdvanceable() { return this.getCurrentState().isAdvanceable(this); } ... @Override public boolean equals(final Object obj) { if (obj == this) { return true; } else if (!(obj instanceof Job)) { return false; } Job otherJob = (Job) obj; return this.getName().equals(otherJob.getName()) && this.getDateOfPayment().equals(otherJob.getDateOfPayment()) && this.getPaymentControlNumber().equals(otherJob.getPaymentControlNumber()) && this.getTruckNumber().equals(otherJob.getTruckNumber()); } @Override public int hashCode() { return this.getName().hashCode() + this.getDateOfPayment().hashCode() + this.getPaymentControlNumber().hashCode() + this.getTruckNumber().hashCode(); } ... } The purpose of JobStateChange is to record when the Job moves through a series of State Changes that are outline in JobState as enums which know about advancement and decrement rules. The interface used to advance Jobs through a series of states is to call Job.advanceState() with a Date and a User. If the Job is advanceable according to rules coded in the enum, then a new StateChange is added to the SortedSet and everyone's happy. If not, an IllegalAdvancementException is thrown. The DDL this generates is as follows: ... drop table job; drop table job_state; ... create table job ( id bigint generated by default as identity, current_state varchar(25), date_of_payment date not null, beginningCheckNumber varchar(8) not null, item_count integer, agency varchar(10) not null, payment_file varchar(25) not null, payment_type varchar(25) not null, endingCheckNumber varchar(8) not null, payment_control_number varchar(4) not null, truck_number varchar(255) not null, wrapping_system_type varchar(15) not null, printer_id bigint, primary key (id), unique (agency, payment_type, payment_file, date_of_payment, payment_control_number, truck_number) ); create table job_state ( job_id bigint not null, acting_user_id bigint not null, date timestamp not null, state varchar(25) not null, primary key (job_id, acting_user_id, date, state) ); ... alter table job add constraint FK19BBD12FB9D70 foreign key (printer_id) references printer; alter table job_state add constraint FK57C2418FED1F0D21 foreign key (acting_user_id) references app_user; alter table job_state add constraint FK57C2418FABE090B3 foreign key (job_id) references job; ... The database is seeded with the following data prior to running tests ... insert into job (id, agency, payment_type, payment_file, payment_control_number, date_of_payment, beginningCheckNumber, endingCheckNumber, item_count, current_state, printer_id, wrapping_system_type, truck_number) values (-3, 'RRB', 'Monthly', 'Monthly','4501','1998-12-01 08:31:16' , '00000001','00040000', 40000, 'UNASSIGNED', null, 'KERN', '02'); insert into job_state (job_id, acting_user_id, date, state) values (-3, -1, '1998-11-30 08:31:17', 'UNASSIGNED'); ... After the database schema is automatically generated and rebuilt by the Hibernate tool. The following test runs fine up until the call to Session.flush() ... @ContextConfiguration(locations = { "/applicationContext-data.xml", "/applicationContext-service.xml" }) public class JobDaoIntegrationTest extends AbstractTransactionalJUnit4SpringContextTests { @Autowired private JobDao jobDao; @Autowired private SessionFactory sessionFactory; @Autowired private UserService userService; @Autowired private PrinterService printerService; ... @Test public void saveJob_JobAdvancedToAssigned_AllExpectedStateChanges() { //Get an unassigned Job Job job = this.jobDao.getJob(-3L); assertEquals(JobState.UNASSIGNED, job.getCurrentState()); Date advancedToUnassigned = new GregorianCalendar(1998, 10, 30, 8, 31, 17).getTime(); assertEquals(advancedToUnassigned, job.getStateChange(JobState.UNASSIGNED).getDate()); //Satisfy advancement constraints and advance job.setPrinter(this.printerService.getPrinter(-1L)); Date advancedToAssigned = new Date(); job.advanceState( this.userService.getUserByUsername("admin"), advancedToAssigned); assertEquals(JobState.ASSIGNED, job.getCurrentState()); assertEquals(advancedToUnassigned, job.getStateChange(JobState.UNASSIGNED).getDate()); assertEquals(advancedToAssigned, job.getStateChange(JobState.ASSIGNED).getDate()); //Persist to DB this.sessionFactory.getCurrentSession().flush(); ... } ... } The error thrown is SQLCODE=-803, SQLSTATE=23505: could not insert collection rows: [jaci.model.job.Job.stateChanges#-3] org.hibernate.exception.ConstraintViolationException: could not insert collection rows: [jaci.model.job.Job.stateChanges#-3] at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:94) at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66) at org.hibernate.persister.collection.AbstractCollectionPersister.insertRows(AbstractCollectionPersister.java:1416) at org.hibernate.action.CollectionUpdateAction.execute(CollectionUpdateAction.java:86) at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:279) at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:263) at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:170) at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:321) at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:50) at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1027) at jaci.dao.JobDaoIntegrationTest.saveJob_JobAdvancedToAssigned_AllExpectedStateChanges(JobDaoIntegrationTest.java:98) at org.springframework.test.context.junit4.SpringTestMethod.invoke(SpringTestMethod.java:160) at org.springframework.test.context.junit4.SpringMethodRoadie.runTestMethod(SpringMethodRoadie.java:233) at org.springframework.test.context.junit4.SpringMethodRoadie$RunBeforesThenTestThenAfters.run(SpringMethodRoadie.java:333) at org.springframework.test.context.junit4.SpringMethodRoadie.runWithRepetitions(SpringMethodRoadie.java:217) at org.springframework.test.context.junit4.SpringMethodRoadie.runTest(SpringMethodRoadie.java:197) at org.springframework.test.context.junit4.SpringMethodRoadie.run(SpringMethodRoadie.java:143) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.invokeTestMethod(SpringJUnit4ClassRunner.java:160) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:97) Caused by: com.ibm.db2.jcc.b.lm: DB2 SQL Error: SQLCODE=-803, SQLSTATE=23505, SQLERRMC=1;ACI_APP.JOB_STATE, DRIVER=3.50.152 at com.ibm.db2.jcc.b.wc.a(wc.java:575) at com.ibm.db2.jcc.b.wc.a(wc.java:57) at com.ibm.db2.jcc.b.wc.a(wc.java:126) at com.ibm.db2.jcc.b.tk.b(tk.java:1593) at com.ibm.db2.jcc.b.tk.c(tk.java:1576) at com.ibm.db2.jcc.t4.db.k(db.java:353) at com.ibm.db2.jcc.t4.db.a(db.java:59) at com.ibm.db2.jcc.t4.t.a(t.java:50) at com.ibm.db2.jcc.t4.tb.b(tb.java:200) at com.ibm.db2.jcc.b.uk.Gb(uk.java:2355) at com.ibm.db2.jcc.b.uk.e(uk.java:3129) at com.ibm.db2.jcc.b.uk.zb(uk.java:568) at com.ibm.db2.jcc.b.uk.executeUpdate(uk.java:551) at org.hibernate.jdbc.NonBatchingBatcher.addToBatch(NonBatchingBatcher.java:46) at org.hibernate.persister.collection.AbstractCollectionPersister.insertRows(AbstractCollectionPersister.java:1389) Therein lies my problem… A nearly identical Class set (in fact, so identical that I've been chomping at the bit to make it a single class that serves both business entities) runs absolutely fine. It is identical except for name. Instead of Job it's Web. Instead of JobStateChange it's WebStateChange. Instead of JobState it's WebState. Both Job and Web's SortedSet of StateChanges are mapped as a Hibernate CollectionOfElements. Both are @Embeddable. Both are SortType.Natural. Both are backed by an Enumeration with some advancement rules in it. And yet when a nearly identical test is run for Web, no issue is discovered and the data flushes fine. For the sake of brevity I won't include all of the Web classes here, but I will include the test and if anyone wants to see the actual sources, I'll include them (just leave a comment). The data seed: insert into web (id, stock_type, pallet, pallet_id, date_received, first_icn, last_icn, shipment_id, current_state) values (-1, 'PF', '0011', 'A', '2008-12-31 08:30:02', '000000001', '000080000', -1, 'UNSTAGED'); insert into web_state (web_id, date, state, acting_user_id) values (-1, '2008-12-31 08:30:03', 'UNSTAGED', -1); The test: ... @ContextConfiguration(locations = { "/applicationContext-data.xml", "/applicationContext-service.xml" }) public class WebDaoIntegrationTest extends AbstractTransactionalJUnit4SpringContextTests { @Autowired private WebDao webDao; @Autowired private UserService userService; @Autowired private SessionFactory sessionFactory; ... @Test public void saveWeb_WebAdvancedToNewState_AllExpectedStateChanges() { Web web = this.webDao.getWeb(-1L); Date advancedToUnstaged = new GregorianCalendar(2008, 11, 31, 8, 30, 3).getTime(); assertEquals(WebState.UNSTAGED, web.getCurrentState()); assertEquals(advancedToUnstaged, web.getState(WebState.UNSTAGED).getDate()); Date advancedToStaged = new Date(); web.advanceState( this.userService.getUserByUsername("admin"), advancedToStaged); this.sessionFactory.getCurrentSession().flush(); web = this.webDao.getWeb(web.getId()); assertEquals( "Web should have moved to STAGED State.", WebState.STAGED, web.getCurrentState()); assertEquals(advancedToUnstaged, web.getState(WebState.UNSTAGED).getDate()); assertEquals(advancedToStaged, web.getState(WebState.STAGED).getDate()); assertNotNull(web.getState(WebState.UNSTAGED)); assertNotNull(web.getState(WebState.STAGED)); } ... } As you can see, I assert that the Web was reconstituted the way I expect, I advance it, flush it to the DB, and then re-get it and verify that the states are as I expect. Everything works perfectly. Not so with Job. A possibly pertinent detail: the reconstitution code works fine if I cease to map JobStateChange.data as a TIMESTAMP and instead as a DATE, and ensure that all of the StateChanges always occur on different Dates. The problem is that this particular business entity can go through many state changes in a single day and so it needs to be sorted by time stamp rather than by date. If I don't do this then I can't sort the StateChanges correctly. That being said, WebStateChange.date is also mapped as a TIMESTAMP and so I again remain absolutely befuddled as to where this error is arising from. I tried to do a fairly thorough job of giving all of the technical details of the implementation but as this particular question is very implementation specific, if I missed anything just let me know in the comments and I'll include it. Thanks so much for your help! UPDATE: Since it turns out to be important to the solution of my problem, I have to include the pertinent bits of the WebStateChange class as well. ... @Embeddable public class WebStateChange implements Comparable<WebStateChange> { @Temporal(TemporalType.TIMESTAMP) @Column(nullable = false) private Date date; @Enumerated(EnumType.STRING) @Column(nullable = false, length = WebState.FIELD_LENGTH) private WebState state; @ManyToOne(fetch = FetchType.LAZY) @JoinColumn(name = "acting_user_id", nullable = false) private User actingUser; ... WebStateChange( final WebState state, final User actingUser, final Date date) { ExceptionUtils.illegalNullArgs(state, actingUser, date); this.state = state; this.actingUser = actingUser; this.date = new Date(date.getTime()); } @Override public int compareTo(final WebStateChange otherStateChange) { return this.date.compareTo(otherStateChange.date); } @Override public boolean equals(final Object candidate) { if (this == candidate) { return true; } else if (!(candidate instanceof WebStateChange)) { return false; } WebStateChange candidateWebState = (WebStateChange) candidate; return this.getState() == candidateWebState.getState() && this.getUser().equals(candidateWebState.getUser()) && this.getDate().equals(candidateWebState.getDate()); } @Override public int hashCode() { return this.getState().hashCode() + this.getUser().hashCode() + this.getDate().hashCode(); } ... }

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  • Idiomatic default sort using WCF RIA, EF4, Silverlight?

    - by Duncan Bayne
    I've got two Silverlight 4.0 ComboBoxes; the second displays the children of the entity selected in the first: <ComboBox Name="cmbThings" ItemsSource="{Binding Path=Things,Mode=TwoWay}" DisplayMemberPath="Name" SelectionChanged="CmbThingsSelectionChanged" /> <ComboBox Name="cmbChildThings" ItemsSource="{Binding Path=SelectedThing.ChildThings,Mode=TwoWay}" DisplayMemberPath="Name" /> The code behind the view provides a (simple, hacky) way to databind those ComboBoxes, by loading Entity Framework 4.0 entities through a WCF RIA service: public EntitySet<Thing> Things { get; private set; } public Thing SelectedThing { get; private set; } protected override void OnNavigatedTo(NavigationEventArgs e) { var context = new SortingDomainContext(); context.Load(context.GetThingsQuery()); context.Load(context.GetChildThingsQuery()); Things = context.Things; DataContext = this; } private void CmbThingsSelectionChanged(object sender, SelectionChangedEventArgs e) { SelectedThing = (Thing) cmbThings.SelectedItem; if (PropertyChanged != null) { PropertyChanged.Invoke(this, new PropertyChangedEventArgs("SelectedThing")); } } public event PropertyChangedEventHandler PropertyChanged; What I'd like to do is have both combo boxes sort their contents alphabetically, and I'd like to specify that behaviour in the XAML if at all possible. Could someone please tell me what is the idiomatic way of doing this with the SL4 / EF4 / WCF RIA technology stack?

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  • Why is ExecuteFunction method only available through base.ExecuteFunction in a child class of Object

    - by Matt
    I'm trying to call ObjectContext.ExecuteFunction from my objectcontext object in the repository of my site. The repository is generic, so all I have is an ObjectContext object, rather than one that actually represents my specific one from the Entity Framework. Here's an example of code that was generated that uses the ExecuteFunction method: [global::System.CodeDom.Compiler.GeneratedCode("System.Data.Entity.Design.EntityClassGenerator", "4.0.0.0")] public global::System.Data.Objects.ObjectResult<ArtistSearchVariation> FindSearchVariation(string source) { global::System.Data.Objects.ObjectParameter sourceParameter; if ((source != null)) { sourceParameter = new global::System.Data.Objects.ObjectParameter("Source", source); } else { sourceParameter = new global::System.Data.Objects.ObjectParameter("Source", typeof(string)); } return base.ExecuteFunction<ArtistSearchVariation>("FindSearchVariation", sourceParameter); } But what I would like to do is something like this... public class Repository<E, C> : IRepository<E, C>, IDisposable where E : EntityObject where C : ObjectContext { private readonly C _ctx; // ... public ObjectResult<E> ExecuteFunction(string functionName, params[]) { // Create object parameters return _ctx.ExecuteFunction<E>(functionName, /* parameters */) } } Anyone know why I have to call ExecuteFunction from base instead of _ctx? Also, is there any way to do something like I've written out? I would really like to keep my repository generic, but with having to execute stored procedures it's looking more and more difficult... Thanks, Matt

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  • Changing data in a django modelform

    - by Matt Hampel
    I get data in from POST and validate it via this standard snippet: entry_formset = EntryFormSet(request.POST, request.FILES, prefix='entries') if entry_formset.is_valid(): .... The EntryFormSet modelform overrides a foreign key field widget to present a text field. That way, the user can enter an existing key (suggested via an Ajax live search), or enter a new key, which will be seamlessly added. I use this try-except block to test if the object exists already, and if it doesn't, I add it. entity_name = request.POST['entries-0-entity'] try: entity = Entity.objects.get(name=entity_name) except Entity.DoesNotExist: entity = Entity(name=entity_name) entity.slug = slugify(entity.name) entity.save() However, I now need to get that entity back into the entry_formset. It thinks that entries-0-entity is a string (that's how it came in); how can I directly access that value of the entry_formset and get it to take the object reference instead?

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  • Cross join (pivot) with n-n table containing values

    - by Styx31
    I have 3 tables : TABLE MyColumn ( ColumnId INT NOT NULL, Label VARCHAR(80) NOT NULL, PRIMARY KEY (ColumnId) ) TABLE MyPeriod ( PeriodId CHAR(6) NOT NULL, -- format yyyyMM Label VARCHAR(80) NOT NULL, PRIMARY KEY (PeriodId) ) TABLE MyValue ( ColumnId INT NOT NULL, PeriodId CHAR(6) NOT NULL, Amount DECIMAL(8, 4) NOT NULL, PRIMARY KEY (ColumnId, PeriodId), FOREIGN KEY (ColumnId) REFERENCES MyColumn(ColumnId), FOREIGN KEY (PeriodId) REFERENCES MyPeriod(PeriodId) ) MyValue's rows are only created when a real value is provided. I want my results in a tabular way, as : Column | Month 1 | Month 2 | Month 4 | Month 5 | Potatoes | 25.00 | 5.00 | 1.60 | NULL | Apples | 2.00 | 1.50 | NULL | NULL | I have successfully created a cross-join : SELECT MyColumn.Label AS [Column], MyPeriod.Label AS [Period], ISNULL(MyValue.Amount, 0) AS [Value] FROM MyColumn CROSS JOIN MyPeriod LEFT OUTER JOIN MyValue ON (MyValue.ColumnId = MyColumn.ColumnId AND MyValue.PeriodId = MyPeriod.PeriodId) Or, in linq : from p in MyPeriods from c in MyColumns join v in MyValues on new { c.ColumnId, p.PeriodId } equals new { v.ColumnId, v.PeriodId } into values from nv in values.DefaultIfEmpty() select new { Column = c.Label, Period = p.Label, Value = nv.Amount } And seen how to create a pivot in linq (here or here) : (assuming MyDatas is a view with the result of the previous query) : from c in MyDatas group c by c.Column into line select new { Column = line.Key, Month1 = line.Where(l => l.Period == "Month 1").Sum(l => l.Value), Month2 = line.Where(l => l.Period == "Month 2").Sum(l => l.Value), Month3 = line.Where(l => l.Period == "Month 3").Sum(l => l.Value), Month4 = line.Where(l => l.Period == "Month 4").Sum(l => l.Value) } But I want to find a way to create a resultset with, if possible, Month1, ... properties dynamic. Note : A solution which results in a n+1 query : from c in MyDatas group c by c.Column into line select new { Column = line.Key, Months = from l in line group l by l.Period into period select new { Period = period.Key, Amount = period.Sum(l => l.Value) } }

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  • How do you cast a LinqToSql Table<TEntity> as a Table<IEntity> where TEntity : IEntity?

    - by DanM
    I'm trying to use DbLinq with a SQLite database, but I'm running into a problem when I try to cast an ITable as a Queryable<TEntity>. There is a known bug in DbLinq (Issue 211), which might be the source of my problem, but I wanted to make sure my code is sound and, if it is, find out if there might be something I can do to work around the bug. Here is the generic repository method that attempts to do the cast: public IQueryable<TEntity> GetAll() { return Table.Cast<TEntity>(); // Table is an ITable } This compiles, but if I pass in the interface IPerson for TEntity and the type of the entities in the table is Person (where Person : IPerson), I'm getting this error from DbLinq: S0133: Implement QueryMethod Queryable.Cast. Why am I trying to do this? I have a library project that doesn't know the type of the entity until runtime, but it does know the interface for the entity. So, I'm trying to cast to the interface type so that my library project can consume the data. Questions: Am I attempting an impossible cast or is this definitely a bug in DbLinq? How else could I go about solving my problem?

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  • ASP.Net MVC Object Reference in Edit View when using DropDownListFor()

    - by hermiod
    This question is related to another I ask recently, it can be found here for some background information. Here is the code in the Edit ActionResult: public virtual ActionResult Edit(int id) { ///Set data for DropDownLists. ViewData["MethodList"] = tr.ListMethods(); ViewData["GenderList"] = tr.ListGenders(); ViewData["FocusAreaList"] = tr.ListFocusAreas(); ViewData["SiteList"] = tr.ListSites(); ViewData["TypeList"] = tr.ListTalkbackTypes(); ViewData["CategoryList"] = tr.ListCategories(); return View(tr.GetTalkback(id)); } I add lists to the ViewData to use in the dropdownlists, these are all IEnumerable and are all returning values. GetTalkback() returns an Entity framework object of type Talkback which is generated from the Talkback table. The DropDownListFor code is: <%: Html.DropDownListFor(model=>model.method_id,new SelectList(ViewData["MethodList"] as IEnumerable<SelectListItem>,"Value","Text",Model.method_id)) %> The record I am viewing has values in all fields. When I click submit on the View, I get an Object reference not set to an instance of an object. error on the above line. There are a number of standard fields in the form prior to this, so the error is only occurring on dropdown lists, and it is occurring on all of them. Any ideas? This is my first foray in to MVC, C#, and Entity so I am completely lost!

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  • EF 4.0 : Save Changes Retry Logic

    - by BGR
    Hi, I would like to implement an application wide retry system for all entity SaveChanges method calls. Technologies: Entity framework 4.0 .Net 4.0 namespace Sample.Data.Store.Entities { public partial class StoreDB { public override int SaveChanges(System.Data.Objects.SaveOptions options) { for (Int32 attempt = 1; ; ) { try { return base.SaveChanges(options); } catch (SqlException sqlException) { // Increment Trys attempt++; // Find Maximum Trys Int32 maxRetryCount = 5; // Throw Error if we have reach the maximum number of retries if (attempt == maxRetryCount) throw; // Determine if we should retry or abort. if (!RetryLitmus(sqlException)) throw; else Thread.Sleep(ConnectionRetryWaitSeconds(attempt)); } } } static Int32 ConnectionRetryWaitSeconds(Int32 attempt) { Int32 connectionRetryWaitSeconds = 2000; // Backoff Throttling connectionRetryWaitSeconds = connectionRetryWaitSeconds * (Int32)Math.Pow(2, attempt); return (connectionRetryWaitSeconds); } /// <summary> /// Determine from the exception if the execution /// of the connection should Be attempted again /// </summary> /// <param name="exception">Generic Exception</param> /// <returns>True if a a retry is needed, false if not</returns> static Boolean RetryLitmus(SqlException sqlException) { switch (sqlException.Number) { // The service has encountered an error // processing your request. Please try again. // Error code %d. case 40197: // The service is currently busy. Retry // the request after 10 seconds. Code: %d. case 40501: //A transport-level error has occurred when // receiving results from the server. (provider: // TCP Provider, error: 0 - An established connection // was aborted by the software in your host machine.) case 10053: return (true); } return (false); } } } The problem: How can I run the StoreDB.SaveChanges to retry on a new DB context after an error occured? Something simular to Detach/Attach might come in handy. Thanks in advance! Bart

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  • How to tell what name RIA Services/EF Model uses for Associations?

    - by Nick Gotch
    Hi, I'm working on a C#.NET 3.5 WCF RIA Services app and having an issue with my Entity Framework model. My entity Foo is mapped to a DB table and has a primary key called FooId. My Bar is mapped to a DB view. I've selectively designed this view to generate a composite key in the EF using two of the columns (by making sure they were non-nullable and the others are all nullable. This was done using NULLIF and ISNULL in the view design.) I'm able to add this view to the model with no problem but I keep running into an issue when I try to map an association between the two. Foo should contain many Bars but I keep getting the following error when I add the association: Unable to retrieve AssociationType for association 'FK_Bar_Foo' According to this page, it looks like this might work if I can properly name the association (since RIA Services looks for specific names.) I've tried several variants of names that match the pattern of other associations with no success. Does anyone know if there's a place I can look to find out what name it's looking for? Thanks,

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  • How much business logic belongs in RIA services layer?

    - by jkohlhepp
    I have been experimenting recently with Silverlight, RIA Services, and Entity Framework using .NET 4.0. I'm trying to figure out if that stack makes sense for use in any of my upcoming projects. It certainly seems like these technologies can be very productive for developing applications, but I'm struggling to decide how an application on top of this stack should be architected. The main issue I have is that in most of the demos I've seen most of the business logic ends up as DataAnnotations and custom validations in the RIA Services domain service class. This seems inappropriate to me. I view the domain service as basically a glorified web service that happens to make it easy to push information to the client. But most of what I've seen seems to orient the domain service as the main source of business logic in the application. So, my questions: What is the best location for business logic (rules, validations, behaviors, authorization) in an application using this stack? Are there any guidelines published at an architectural level for using this stack? My questions pertain to large, complex, and long-lived applications. Obviously for an application of only a few screens this is less of a concern. Edit: Another thing I meant to mention is that obviously you can make the domain service class stupid, but then you lose a lot of the automagic entity information (e.g. validations) being pushed to the client. And then if you lose that is there any point to using RIA services?

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  • Problem with .Contains

    - by Rene
    Hello there, I have a little problem which i can't solve. I want to use an SQL-In-Statement in Linq. I've read in this Forum and in other Forums that I have to use the .Contains (with reverse-thinking-notation :-)). As input i have a List of Guids. I first copied them into an array and then did something like that : datatoget = (from p in objectContext.MyDataSet where ArrayToSearch.Contains(p.Subtable.Id.ToString()) select p).ToList(); datatoget is the result in which all records matching the Subtable.Id (which is a Guid) should be stored. Subtable is a Detail-Table from MyData, and the Id is a Guid-Type. I've tried several things (Convert Guid to String, and then using .Contains, etc), but I always get an Exception which says : 'Linq to Entities' doesn't recognize the Method 'Boolean Contains(System.Guid) and is not able to Translate this method into a memory expression. (Something like that, because I'm using the German Version of VS2008) I am using L2E with .NET 3.5 and am programming in C# with VS 2008. I've read several Examples, but it doesn't work. Is it perhaps because of using Guid's instead of strings ? I've also tried to write my own compare-function, but I don't know how to integrate it so that .NET calls my function for comparing.

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  • WCF Data Services - neither .Expand or .LoadProperty seems to do what I need

    - by TomK
    I am building a school management app where they track student tardiness and absences. I've got three entities to help me in this. A Students entity (first name, last name, ID, etc.); a SystemAbsenceTypes entity with SystemAbsenceTypeID values for Late, Absent-with-Reason, Absent-without-Reason; and a cross-reference table called StudentAbsences (matching the student IDs with the absence-type ID, plus a date, and a Notes field). What I want to do is query my entities for a given student, and then add up the number of each kind of Absence, for a given date range. I prepare my currentStudent object without a problem, then I do this... Me.Data.LoadProperty(currentStudent, "StudentAbsences") 'Loads the cross-ref data lblDaysLate.Text = (From ab In currentStudent.StudentAbsences Where ab.SystemAbsenceTypes.SystemAbsenceTypeID = Common.enuStudentAbsenceTypes.Late).Count.ToString ...and this second line fails, complaining it has no value for an object. I presume the problem is that while it DOES see that there are (let's say) four absences for the currentStudent (ie, currentStudent.StudentAbsences.Count = 4) -- it can't yet "peer into" each one of the absences to look at its type. How do I use .Expand or .LoadProperty to make this happen? I tried fiddling with .LoadProperty but it doesn't take a two-level syntax like so... Data.LoadProperty(currentStudent,"StudentAbsences.SystemAbsenceTypeID") or the like. Is there some other technique?

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  • EF + UnitOfWork + SharePoint RunWithElevatedPrivileges

    - by Lorenzo
    In our SharePoint application we have used the UnitOfWork + Repository patterns together with Entity Framework. To avoid the usage of the passthrough authentication we have developed a piece of code that impersonate a single user before creating the ObjectContext instance in a similar way that is described in "Impersonating user with Entity Framework" on this site. The only difference between our code and the referred question is that, to do the impersonation, we are using RunWithElevatedPrivileges to impersonate the Application Pool identity as in the following sample. SPSecurity.RunWithElevatedPrivileges(delegate() { using (SPSite site = new SPSite(url)) { _context = new MyDataContext(ConfigSingleton.GetInstance().ConnectionString); } }); We have done this way because we expected that creating the ObjectContext after impersonation and, due to the fact that Repositories are receiving the impersonated ObjectContext would solve our requirement. Unfortunately it's not so easy. In fact we experienced that, even if the ObjectContext is created before and under impersonation circumstances, the real connection is made just before executing the query, and so does not use impersonation, which break our requirement. I have checked the ObjectContext class to see if there was any event through which we can inject the impersonation but unfortunately found nothing. Any help?

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  • Update one-to-many EntityKey using Foreign Key

    - by User.Anonymous
    To use by the easiest way Entity Framework, I use partial class to add Foreign Key on most important Entities Model. For example, I have an Entity "CONTACT" which have "TITLE", "FUNCTION" and others. When I update a CONTACT, with this code, Foreign Key are automatically updated : public int? TitId { get { if (this.TITLE_TIT != null) return TITLE_TIT.TIT_ID; return new Nullable<int>(); } set { this.TITLE_TITReference.EntityKey = new System.Data.EntityKey("Entities.TITLE_TIT", "TIT_ID", value); } } But I have a join with ACTIVITY, that can have many CONTACT, and I don't know how to update EntityKey on setters. public IEnumerable<EntityKeyMember> ActId { get { List<EntityKeyMember> lst = new List<EntityKeyMember>(); if (this.ACT_CON2 != null) { foreach (ACT_CON2 id in this.ACT_CON2.ToList()) { EntityKeyMember key = new EntityKeyMember(id.CON_ID.ToString(),id.ACT_ID); lst.Add(key); } } return lst; } set { this.ACT_CON2.EntityKey = new System.Data.EntityKey("Entities.ACT_CON2", value); } } How set many EntityKey ? Thank you.

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  • How to find unique values in jagged array

    - by David Liddle
    I would like to know how I can count the number of unique values in a jagged array. My domain object contains a string property that has space delimitered values. class MyObject { string MyProperty; //e.g = "v1 v2 v3" } Given a list of MyObject's how can I determine the number of unique values? The following linq code returns an array of jagged array values. A solution would be to store a temporary single array of items, looped through each jagged array and if values do not exist, to add them. Then a simple count would return the unique number of values. However, was wondering if there was a nicer solution. db.MyObjects.Where(t => !String.IsNullOrEmpty(t.MyProperty)) .Select(t => t.Categories.Split(new char[] { ' ' }, StringSplitOptions.RemoveEmptyEntries)) .ToArray() Below is a more readable example: array[0] = { "v1", "v2", "v3" } array[1] = { "v1" } array[2] = { "v4", "v2" } array[3] = { "v1", "v5" } From all values the unique items are v1, v2, v3, v4, v5. The total number of unique items is 5. Is there a solution, possibly using linq, that returns either only the unique values or returns the number of unique values?

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  • Hibernate and parent/child relations

    - by Marco
    Hi to all, I'm using Hibernate in a Java application, and i feel that something could be done better for the management of parent/child relationships. I've a complex set of entities, that have some kind of relationships between them (one-to-many, many-to-many, one-to-one, both unidirectional and bidirectional). Every time an entity is saved and it has a parent, to estabilish the relationship the parent has to add the child to its collection (considering a one-to-may relationship). For example: Parent p = (Parent) session.load(Parent.class, pid); Child c = new Child(); c.setParent(p); p.getChildren().add(c); session.save(c); session.flush(); In the same way, if i remove a child then i have to explicitly remove it from the parent collection too. Child c = (Child) session.load(Child.class, cid); session.delete(c); Parent p = (Parent) session.load(Parent.class, pid); p.getChildren().remove(c); session.flush(); I was wondering if there are some best practices out there to do this jobs in a different way: when i save a child entity, automatically add it to the parent collection. If i remove a child, automatically update the parent collection by removing the child, etc. For example, Child c = new Child(); c.setParent(p); session.save(c); // Automatically update the parent collection session.flush(); or Child c = (Child) session.load(Child.class, cid); session.delete(c); // Automatically updates its parents (could be more than one) session.flush(); Anyway, it would not be difficult to implement this behaviour, but i was wondering if exist some standard tools or well known libraries that deals with this issue. And, if not, what are the reasons? Thanks

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  • What is the best database structure for this scenario?

    - by Ricketts
    I have a database that is holding real estate MLS (Multiple Listing Service) data. Currently, I have a single table that holds all the listing attributes (price, address, sqft, etc.). There are several different property types (residential, commercial, rental, income, land, etc.) and each property type share a majority of the attributes, but there are a few that are unique to that property type. My question is the shared attributes are in excess of 250 fields and this seems like too many fields to have in a single table. My thought is I could break them out into an EAV (Entity-Attribute-Value) format, but I've read many bad things about that and it would make running queries a real pain as any of the 250 fields could be searched on. If I were to go that route, I'd literally have to pull all the data out of the EAV table, grouped by listing id, merge it on the application side, then run my query against the in memory object collection. This also does not seem very efficient. I am looking for some ideas or recommendations on which way to proceed. Perhaps the 250+ field table is the only way to proceed. Just as a note, I'm using SQL Server 2012, .NET 4.5 w/ Entity Framework 5, C# and data is passed to asp.net web application via WCF service. Thanks in advance.

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  • XDocument.Parse fails due to resolution error, how to disable resolution

    - by Frank Krueger
    I am trying to parse the contents of http://feeds.feedburner.com/riabiz using XDocument.Parse(string) (because it gets cached in a DB.) However, it keeps failing with the below stack trace when it tries to resolve some URIs in that XML. I don't care about validation or any of that XML nonsense, I just want the structure parsed. How can I use XDocument without this URI resolution? System.ArgumentException: The specified path is not of a legal form (empty). at System.IO.Path.InsecureGetFullPath (System.String path) [0x00000] in :0 at System.IO.Path.GetFullPath (System.String path) [0x00000] in :0 at System.Xml.XmlResolver.ResolveUri (System.Uri baseUri, System.String relativeUri) [0x00000] in :0 at System.Xml.XmlUrlResolver.ResolveUri (System.Uri baseUri, System.String relativeUri) [0x00000] in :0 at Mono.Xml2.XmlTextReader.ReadStartTag () [0x00000] in :0 at Mono.Xml2.XmlTextReader.ReadContent () [0x00000] in :0 at Mono.Xml2.XmlTextReader.Read () [0x00000] in :0 at System.Xml.XmlTextReader.Read () [0x00000] in :0 at Mono.Xml.XmlFilterReader.Read () [0x00000] in :0 at Mono.Xml.XmlFilterReader.Read () [0x00000] in :0 at System.Xml.XmlReader.ReadEndElement () [0x00000] in :0 at System.Xml.Linq.XElement.LoadCore (System.Xml.XmlReader r, LoadOptions options) [0x00000] in :0 at System.Xml.Linq.XNode.ReadFrom (System.Xml.XmlReader r, LoadOptions options) [0x00000] in :0 ...

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  • Problems finding classes in namespace and testing extend expected parent

    - by Matt
    So I am in the process of building a site in ASP.Net MVC, and in the process I am adding certain things to my Site.Master I want to make sure that all of my model classes extend a certain base class that contains all of the pieces the Site.Master needs to be operable. I want to test to make sure this assumption isn't broken (I believe this will save me time when I forget about it and can't figure out why a new combination isn't working.) I wrote a test that I thought would help with this, but I am running into two problems. First it isn't finding the one example model class I have so far in the LINQ call all of a sudden, I am admittedly still a bit new to LINQ. Second, I had it finding the class earlier, but I couldn't get it to verify that the class inherits from the base class. Here is the example test. [Test] public void AllModelClassesExtendAbstractViewModel() { var abstractViewModelType = typeof (AbstractViewModel); Assembly baseAssembly = Assembly.GetAssembly(abstractViewModelType); var modelTypes = baseAssembly.GetTypes() .Where(assemblyType => (assemblyType.Namespace.EndsWith("Models") && assemblyType.Name != "AbstractViewModel")) .Select(assemblyType => assemblyType); foreach (var modelType in modelTypes) { Assert.That(modelType.IsSubclassOf(abstractViewModelType), Is.True , modelType.Name + " does not extend AbstractViewModel"); } }

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  • How can you pre-define a variable that will contain an anonymous type?

    - by HitLikeAHammer
    In the simplified example below I want to define result before it is assinged. The linq queries below return lists of anonymous types. result will come out of the linq queries as an IEnumerable<'a but I can't define it that way at the top of the method. Is what I am trying to do possible (in .NET 4)? bool large = true; var result = new IEnumerable(); //This is wrong List<int> numbers = new int[]{1,2,3,4,5,6,7,8,9,10}.ToList<int>(); if (large) { result = from n in numbers where n > 5 select new { value = n }; } else { result = from n in numbers where n < 5 select new { value = n }; } foreach (var num in result) { Console.WriteLine(num.value); } EDIT: To be clear I know that I do not need anonymous types in the example above. It is just to illustrate my question with a small, simple example.

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  • How to avoid using the same identifier for Class Names and Property Names?

    - by Wololo
    Here are a few example of classes and properties sharing the same identifier: public Coordinates Coordinates { get; set; } public Country Country { get; set; } public Article Article { get; set; } public Color Color { get; set; } public Address Address { get; set; } This problem occurs more frequently when using POCO with the Entity Framework as the Entity Framework uses the Property Name for the Relationships. So what to do? Use non-standard class names? public ClsCoordinates Coordinates { get; set; } public ClsCountry Country { get; set; } public ClsArticle Article { get; set; } public ClsColor Color { get; set; } public ClsAddress Address { get; set; } public ClsCategory Category { get; set; } Yuk Or use more descriptive Property Names? public Coordinates GeographicCoordinates { get; set; } public Country GeographicCountry { get; set; } public Article WebArticle { get; set; } public Color BackgroundColor { get; set; } public Address HomeAddress { get; set; } public Category ProductCategory { get; set; } Less than ideal, but can live with it I suppose. Or JUST LIVE WITH IT? What are you best practices?

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  • Does Hibernate support one-to-one associations as pkeys?

    - by Andrzej Doyle
    Hi all, Can anyone tell me whether Hibernate supports associations as the pkey of an entity? I thought that this would be supported but I am having a lot of trouble getting any kind of mapping that represents this to work. In particular, with the straight mapping below: @Entity public class EntityBar { @Id @OneToOne(optional = false, mappedBy = "bar") EntityFoo foo // other stuff } I get an org.hibernate.MappingException: "Could not determine type for: EntityFoo, at table: ENTITY_BAR, for columns: [org.hibernate.mapping.Column(foo)]" Diving into the code it seems the ID is always considered a Value type; i.e. "anything that is persisted by value, instead of by reference. It is essentially a Hibernate Type, together with zero or more columns." I could make my EntityFoo a value type by declaring it serializable, but I wouldn't expect this would lead to the right outcome either. I would have thought that Hibernate would consider the type of the column to be integer (or whatever the actual type of the parent's ID is), just like it would with a normal one-to-one link, but this doesn't appear to kick in when I also declare it an ID. Am I going beyond what is possible by trying to combine @OneToOne with @Id? And if so, how could one model this relationship sensibly?

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