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  • Trying to use linq to search based on table with hierarchical data.

    - by Steph
    Duplicate many times over (and also these) I have a table called Types that has the following columns. ID Level Name ParentID (The ID of the parent row) and a table called ParentObject which has the following columns. ID TypeID there are 4 different level (possibly to be expanded to more). So if I had ID: 1 Level: 0 Name: Level0 ParentID: null ID: 2 Level: 1 Name: Level1 ParentID: 1 ID: 3 Level: 2 Name: Level2 ParentID: 2 ID: 4 Level: 3 Name: Level3 ParentID: 3 ID: 5 Level: 4 Name: Level4 ParentID: 4 In the ParentObject table I store the tree by just storing the lowest level ID. So if the ID i have is 4, I know that the tree actually goes Level0 - Level1 - Level2 - Level3 Basically, I need to be able to search all objects for a certain Type, or Type Level 2 for example in a linq statement. Say that the TypeID stored in the ParentObject table is 4, so Level3. But I actually want to search for all ParentObjects where the Level 2 type has an ID of 3. What would be the best way to do this since the id stored could be a level1 or a level2, etc.? Preferably in one linq statement if possible.

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  • Persisting details in Master Detail relation EF4 POCO

    - by Roger Alsing
    Scenario: Entity Framework 4 , POCO templates and Master Detail relation. Lets say I have a master type like this: //partial implementation of master entity partial class Master { public void AddDetail(x,y,z) { var detail = new Detail() { X = x, Y = y, Z = z, }; //add the detail to the master this.Details.Add(detail); } } If I then add a master instance to my context and commit, the details will not be saved: var masterObject = new Master(); masterObject.AddDetail(1,2,3); myContext.MasterSet.AddObject(masterObject); Is there any way to make the details to be persisted by reachabillity when using POCO templates? Or any other way? the Details collection in the Master entity is a FixUpCollection, so it ought to track the changes IMO. So, any ideas how to make this work W/O killing the POCO'ness too much?

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  • linq sort many 2 many question

    - by user169867
    My main entity is called [Contract]. Contract has a many 2 many relationship w/ [Service]. When I query for a list of Contracts I grab the 1st Service available like this: q.Select(c => new ContractSearchResult() { ContractID = c.ContractID, FirstService = c.Contract2Service.FirstOrDefault().Service.Name, ServiceCount = c.Contract2Service.Count, } ).ToList(); q is an IQueryable that has some filtering & paging already applied. (When I display this list I show the FirstService if there's only 1. If 1 I show "My1stService (3)" to show I'm seeing the 1st of 3 services) This works fine. My question is this: Is there any way to sort by FirstService? Or is this impossible? I haven't found a way of expressing this in linq. Any help would be appreciated.

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  • 3 methods for adding a "Product" through Entity Framework. What's the difference?

    - by Kohan
    Reading this MSDN article titled "Working with ObjectSet (Entity Framework)" It shows two examples on how to add a Product.. one for 3.5 and another for 4.0. http://msdn.microsoft.com/en-us/library/ee473442.aspx Through my lack of knowledge I am possibly completely missing something here, but i never added a Product like this: //In .NET Framework 3.5 SP1, use the following code: (ObjectQuery) using (AdventureWorksEntities context = new AdventureWorksEntities()) { // Add the new object to the context. context.AddObject("Products", newProduct); } //New in .NET Framework 4, use the following code: (ObjectSet) using (AdventureWorksEntities context = new AdventureWorksEntities()) { // Add the new object to the context. context.Products.AddObject(newProduct); } I would not have done it either way and just used: // (My familiar way) using (AdventureWorksEntities context = new AdventureWorksEntities()) { // Add the new object to the context. context.AddToProducts(newProduct); } What's the difference between these three ways? Is "My way" just another way of using an ObjectQuery? Thanks, Kohan

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  • LINQ to SQL vs Entity Framework for an app with a future SQL Azure version

    - by Craig L
    I've got a vertical market Dot Net Framework 1.1 C#/WinForms/SQL Server 2000 application. Currently it uses ADO.Net and Microsoft's SQLHelper for CRUD operations. I've successfully converted it to Dot Net Framework 4 C#/WinForms/ SQL Server 2008. What I'd like to do is also offer my customers the ability to use SQL Azure as a backend storage for their data instead of local/LAN SQL Server. If I know SQL Azure is in my application's future, should I: A. Switch to LINQ to SQL B. Swith to Entity Framework C. Stick with ADO.Net and SQLHelper Thanks !

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  • Cannot format first column in WxPython's ListCtrl

    - by Matt Clarke
    If I set the format of the first column in a ListCtrl to align centre (or align right) nothing happens. It works for the other columns. This only happens on Windows - I have tested it on Linux and it works fine. Does anyone know if there is a work-round or other solution? Here is an example based on code found at http://zetcode.com/wxpython/ import wx import sys packages = [('jessica alba', 'pomona', '1981'), ('sigourney weaver', 'new york', '1949'), ('angelina jolie', 'los angeles', '1975'), ('natalie portman', 'jerusalem', '1981'), ('rachel weiss', 'london', '1971'), ('scarlett johansson', 'new york', '1984' )] class Actresses(wx.Frame): def __init__(self, parent, id, title): wx.Frame.__init__(self, parent, id, title, size=(380, 230)) hbox = wx.BoxSizer(wx.HORIZONTAL) panel = wx.Panel(self, -1) self.list = wx.ListCtrl(panel, -1, style=wx.LC_REPORT) self.list.InsertColumn(0, 'name', wx.LIST_FORMAT_CENTRE,width=140) self.list.InsertColumn(1, 'place', wx.LIST_FORMAT_CENTRE,width=130) self.list.InsertColumn(2, 'year', wx.LIST_FORMAT_CENTRE, 90) for i in packages: index = self.list.InsertStringItem(sys.maxint, i[0]) self.list.SetStringItem(index, 1, i[1]) self.list.SetStringItem(index, 2, i[2]) hbox.Add(self.list, 1, wx.EXPAND) panel.SetSizer(hbox) self.Centre() self.Show(True) app = wx.App() Actresses(None, -1, 'actresses') app.MainLoop()

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  • ASP.Net MVC 3 Full Name In DropDownList

    - by tgriffiths
    I am getting a bit confused with this and need a little help please. I am developing a ASP.Net MVC 3 Web application using Entity Framework 4.1. I have a DropDownList on one of my Razor Views, and I wish to display a list of Full Names, for example Tom Jones Michael Jackson James Brown In my Controller I retrieve a List of User Objects, then select the FirstName and LastName of each User, and pass the data to a SelectList. List<User> Requesters = _userService.GetAllUsersByTypeIDOrgID(46, user.organisationID.Value).ToList(); var RequesterNames = from r in Requesters let person = new { UserID = r.userID, FullName = new { r.firstName, r.lastName } } orderby person.FullName ascending select person; viewModel.RequestersList = new SelectList(RequesterNames, "UserID", "FullName"); return View(viewModel); In my Razor View I have the following @Html.DropDownListFor(model => model.requesterID, Model.RequestersList, "Select", new { @class = "inpt_a"}) @Html.ValidationMessageFor(model => model.requesterID) However, when I run the code I get the following error At least one object must implement IComparable. I feel as if I am going about this the wrong way, so could someone please help with this? Thanks.

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  • Linq : problem with primary key

    - by Nickson
    I get the following error message The table/view 'TABLE1' does not have a primary key defined and no valid primary key could be inferred. This table/view has been excluded. To use the entity you will need to review your schema, add the correct keys and uncomment it when I try to add a view to an Entity Data Model. For testing, I have created a very simple view and I still get the error. below is the view definition SELECT DISTINCT TOP (100) PERCENT MIN(id) AS Expr4, MIN(EmpNo) AS Expr1, MIN(Name) AS Expr2, MIN(Category) AS Expr3 FROM dbo.MYView1 GROUP BY id does any one know of a simple work around. I have looked at this thread http://stackoverflow.com/questions/745341/can-ms-sql-views-have-primary-and-foriegn-keys but in my scenario, what is recommended is not applicable. If I could only have the view added to the Model.

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  • Entity Framework Many-To-Many with additional field on Joining Table

    - by Cory G
    I have an entity context that includes three tables (see diagram here). The first is a table that contain products, the second contains recipes. The joining table has fields for IDs in both the products and recipes table as well as a 'bit' field called 'featured'. I've searched and found no example on how to insert only how to select against this type of scenario.Does anyone have any suggestions on how this can be done? Thanks in advance for any help. Cory

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  • Order by descending is not working on LINQ to Entity

    - by Vinni
    Order by descending is not working on LINQ to Entity In the following Query In place of ascending If I keep descending it is not working. Please help me out var hosters = from e in context.Hosters_HostingProviderDetail where e.ActiveStatusID == pendingStateId orderby e.HostingProviderName ascending select e; return hosters.ToList();

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  • how to insert using linq to entity foreign key value?

    - by Gamble
    I have a table (TestTable) for example: ID Name Parentid (FK) and I would like to insert a new record like ID(1) Name(Test) ParentID(5) FK. How can insert a new record into TestTable with linq to entity? var testTable = new TestTable(); testTable.ID = 1; testTable.Name = "TestName"; testTable ... thank you for the working example.

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  • Create a Python User() class that both creates new users and modifies existing users

    - by ensnare
    I'm trying to figure out the best way to create a class that can modify and create new users all in one. This is what I'm thinking: class User(object): def __init__(self,user_id): if user_id == -1 self.new_user = True else: self.new_user = False #fetch all records from db about user_id self._populateUser() def commit(self): if self.new_user: #Do INSERTs else: #Do UPDATEs def delete(self): if self.new_user == False: return False #Delete user code here def _populate(self): #Query self.user_id from database and #set all instance variables, e.g. #self.name = row['name'] def getFullName(self): return self.name #Create a new user >>u = User() >>u.name = 'Jason Martinez' >>u.password = 'linebreak' >>u.commit() >>print u.getFullName() >>Jason Martinez #Update existing user >>u = User(43) >>u.name = 'New Name Here' >>u.commit() >>print u.getFullName() >>New Name Here Is this a logical and clean way to do this? Is there a better way? Thanks.

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  • Is writing eSQL database independent or not?

    - by Robert Koritnik
    Using EF we can use LINQ to read data which is rather simple (especially using fluent calls), but we have less control unless we write eSQL on our own. Is writing eSQL actually data store independent code? So if we decide to change data store, can the same statements still be used? Does writing eSQL strings in your code pose any serious security threats similar to writing TSQL statements as plain strings in C# code? That's why SPs are recommended. Could we still move eSQL scripts outside of code and use some other technique to make them a bit more secure?

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  • How to cache L2E entity without attach/detach?

    - by Eran Betzalel
    The following code will select a key/value table in the DB and will save the result to the cache: using (var db = new TestEntities()) { if(Cache["locName_" + inventoryLocationName] != null) return Cache["locName_" + inventoryLocationName]; var location = db.InventoryLocationsSet.FirstOrDefault( i => i.InventoryLocationName.Equals( inventoryLocationName, StringComparison.CurrentCultureIgnoreCase)); db.Detach(location); // ???? Cache["locName_" + inventoryLocationName] = location; return location; } But it doesn't work well when I'm trying to use the cached object. Of course, the problem is the different ObjectContext, so I use Attach/Detach and then the problem solves but with a codding horror price: db.Attach(locationFromCache); // ???? try { // Use location as foreign key db.SaveChanges(); } finally { db.Detach(locationFromCache); // ???? } So, how can I use cached objects without using attach/detach methods? What happens if more than one user will have to use this cached object? Should I put the whole thing in a CriticalSection?!

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  • How to implement a left outer join in the Entity Framework.

    - by user206736
    I have the following SQL query:- select distinct * from dbo.Profiles profiles left join ProfileSettings pSet on pSet.ProfileKey = profiles.ProfileKey left join PlatformIdentities pId on pId.ProfileKey = profiles.Profilekey I need to convert it to a LinqToEntities expression. I have tried the following:- from profiles in _dbContext.ProfileSet let leftOuter = (from pSet in _dbContext.ProfileSettingSet select new { pSet.isInternal }).FirstOrDefault() select new { profiles.ProfileKey, Internal = leftOuter.isInternal, profiles.FirstName, profiles.LastName, profiles.EmailAddress, profiles.DateCreated, profiles.LastLoggedIn, }; The above query works fine because I haven't considered the third table "PlatformIdentities". Single left outer join works with what I have done above. How do I include PlatformIdentities (the 3rd table) ? I basically want to translate the SQL query I specified at the beginning of this post (which gives me exactly what I need) in to LinqToEntities. Thanks

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  • Entity Framework Custom Query Function

    - by Josh
    I have an Entity Framework 4.0 Entity Object called Revision w/ Nullable DateEffectiveFrom and DateEffectiveTo dates. I was wondering if there was a short-hand way of querying an object's RevisionHistory based on a particular QueryDate date instead of having to use the following query structure: var results = EntityObject.Revisions.Where(x => (x.DateEffectiveFrom == null && x.DateEffectiveTo == null) || (x.DateEffectiveFrom == null && x.DateEffectiveTo >= QueryDate) || (x.DateEffectiveFrom <= QueryDate && x.DateEffectiveTo == null) || (x.DateEffectiveFrom <= QueryDate && x.DateEffectiveTo >= QueryDate)); I've tried creating the following boolean function in the Revision class: partial class Revision { public bool IsEffectiveOn(DateTime date) { return (x.DateEffectiveFrom == null && x.DateEffectiveTo == null) || (x.DateEffectiveFrom == null && x.DateEffectiveTo >= date) || (x.DateEffectiveFrom <= date && x.DateEffectiveTo == null) || (x.DateEffectiveFrom <= date && x.DateEffectiveTo >= date)); } ... } And then updating the query to: var results = EntityObject.Revisions.Where(x => x.IsEffectiveOn(QueryDate)); but this obviously doesn't translate to SQL. Any ideas would be much appreciated.

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  • How can you increase timeout in Linq2Entities?

    - by Russell Steen
    I'm doing a basic select against a view. Unfortunately the result can be slow and I'm getting timeout errors intermittently. How can I increase the timeout? Using .NET 3.5, Sql Server 2000, Linq2Entities I'm using the very basic query List<MyData> result = db.MyData.Where(x.Attribute == search).ToList(); Fixing the query so that it's faster on the DB side is not an option here. Exact Error: "Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding." Update: I'd prefer to just change it for this one query.

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  • Why can't I insert record with foregion key in a single server request?

    - by Eran Betzalel
    I'm tryring to do a simple insert with foregion key, but it seems that I need to use db.SaveChanges() for every record insert. How can I manage to use only one db.SaveChanges() at the end of this program? foreach (var file in files) { db.AddToFileSet(file); db.SaveChanges(); db.AddToDirectorySet( new GlxCustomerPhone { SimIdentifier = file.Name + "Dir", CreationDate = DateTime.UtcNow, file_relation = file }); db.SaveChanges(); }

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  • Linq Query with aggregate function

    - by Billy Logan
    Hello everyone, I am trying to figure out how to go about writing a linq query to perform an aggregate like the sql query below: select d.ID, d.FIRST_NAME, d.LAST_NAME, count(s.id) as design_count from tbldesigner d inner join TBLDESIGN s on d.ID = s.DESIGNER_ID where s.COMPLETED = 1 and d.ACTIVE = 1 group by d.ID, d.FIRST_NAME, d.LAST_NAME Having COUNT(s.id) > 0 If this is even possible with a linq query could somebody please provide me with an example. Thanks in Advance, Billy

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  • Hibernate mapping, on a unmapped class

    - by Jan
    Hi, I' ve got 2 tables... Challenge and ChallengeYear, ChallengeYear is only to create a list of years in challenge. I only want to make Challenge an entity, containing a list of List years. Is this possible? I've looked in to @SecondaryTable together with @JoinColumn and @OneToMany, but neither of those can do the trick, or i am overlooking something. Can someone help me? Greetings, Jan

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  • Order by descending based on condition

    - by Vinni
    Hello All, I want to write a LINQ to Entity query which does order by ascending or descending based on input parameter, Is there any way for that. Following is the my code. Please suggest. public List<Hosters_HostingProviderDetail> GetPendingApproval(SortOrder sortOrder) { List<Hosters_HostingProviderDetail> returnList = new List<Hosters_HostingProviderDetail>(); int pendingStateId = Convert.ToInt32(State.Pending); //If the sort order is ascending if (sortOrder == SortOrder.ASC) { var hosters = from e in context.Hosters_HostingProviderDetail where e.ActiveStatusID == pendingStateId orderby e.HostingProviderName ascending select e; returnList = hosters.ToList<Hosters_HostingProviderDetail>(); return returnList; } else { var hosters = from e in context.Hosters_HostingProviderDetail where e.StateID == pendingStateId orderby e.HostingProviderName descending select e; returnList = hosters.ToList<Hosters_HostingProviderDetail>(); return returnList; } }

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  • Update a record in L2S and L2E

    - by 5YrsLaterDBA
    I was told in L2S, the code for update and insert are the same, db.InsertOnSubmit(row); db.SubmitChanges(); and L2S will check to see if it is a insert or update and act approprately in the background. Is that true? How about L2E? I tested, looks like in L2E it is not like that. Maybe I did something wrong.

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