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Search found 7266 results on 291 pages for 'entity relationship'.

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  • What is difference between Where and Join in linq ?

    - by Freshblood
    hello What is difference between of these 2 queries ? they are completely equal ? from order in myDB.OrdersSet from person in myDB.PersonSet from product in myDB.ProductSet where order.Persons_Id==person.Id && order.Products_Id==product.Id select new { order.Id, person.Name, person.SurName, product.Model,UrunAdi=product.Name }; and from order in myDB.OrdersSet join person in myDB.PersonSet on order.Persons_Id equals person.Id join product in myDB.ProductSet on order.Products_Id equals product.Id select new { order.Id, person.Name, person.SurName, product.Model,UrunAdi=product.Name };

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  • Convert SQL to LINQ in MVC3 with Ninject

    - by Jeff
    I'm using MVC3 and still learning LINQ. I'm having some trouble trying to convert a query to LINQ to Entities. I want to return an employee object. SELECT E.EmployeeID, E.FirstName, E.LastName, MAX(EO.EmployeeOperationDate) AS "Last Operation" FROM Employees E INNER JOIN EmployeeStatus ES ON E.EmployeeID = ES.EmployeeID INNER JOIN EmployeeOperations EO ON ES.EmployeeStatusID = EO.EmployeeStatusID INNER JOIN Teams T ON T.TeamID = ES.TeamID WHERE T.TeamName = 'MyTeam' GROUP BY E.EmployeeID, E.FirstName, E.LastName ORDER BY E.FirstName, E.LastName What I have is a few tables, but I need to get only the newest status based on the EmployeeOpertionDate. This seems to work fine in SQL. I'm also using Ninject and set my query to return Ienumerable. I played around with the group by option but it then returns IGroupable. Any guidance on converting and returning the property object type would be appreciated. Edit: I started writing this out in LINQ but I'm not sure how to properly return the correct type or cast this. public IQueryable<Employee> GetEmployeesByTeam(int teamID) { var q = from E in context.Employees join ES in context.EmployeeStatuses on E.EmployeeID equals ES.EmployeeID join EO in context.EmployeeOperations on ES.EmployeeStatusID equals EO.EmployeeStatusID join T in context.Teams on ES.TeamID equals T.TeamID where T.TeamName == "MyTeam" group E by E.EmployeeID into G select G; return q; } Edit2: This seems to work for me public IQueryable<Employee> GetEmployeesByTeam(int teamID) { var q = from E in context.Employees join ES in context.EmployeeStatuses on E.EmployeeID equals ES.EmployeeID join EO in context.EmployeeOperations.OrderByDescending(eo => eo.EmployeeOperationDate) on ES.EmployeeStatusID equals EO.EmployeeStatusID join T in context.Teams on ES.TeamID equals T.TeamID where T.TeamID == teamID group E by E.EmployeeID into G select G.FirstOrDefault(); return q; }

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  • Save VM properties with EF code first

    - by Julien
    I thought this would be simple but can't find any good examples. public Class BookVm : ImplementsPropertyChanged { public int BookId {get;set;} private bool _favorite; public bool Favorite { get { return _favorite; } set { _favorite = value; OnPropertyChanged("Favorite"); MyDbContext.SaveChanges() // this does not work } } Then in my XAML bound to Book <CheckBox Content="Favorite" IsChecked="{Binding Favorite}" /> How and when do I call SaveChanges() on my DatabaseContext? I don't want to implement a save button. If I intercept the PropertyChange event and call SaveChanges, nothing seems to happen. My object is modified in memory but the database does not see a change. My BookVm class is created on application startup like so: foreach (var book in MyDbContext.Books) Books.Add(book); Where Books is an ObservableCollection<Book> in my MainWindowVm

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  • Succinct But Complete Example of WPF App?

    - by Eric J.
    Is there a succinct but complete example project or tutorial that brings together the pieces of the Microsoft stack for a complete application? WPF MVVM Business Objects EF Database I find plenty for WPF and plenty for EF, but am having trouble fully understanding how the EF generated classes relate to business objects, and how those business objects in turn fit into the MVVM pattern.

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  • EF4 Code-First CTP5 Many-to-one

    - by Kevin McKelvin
    I've been trying to get EF4 CTP5 to play nice with an existing database, but struggling with some basic mapping issues. I have two model classes so far: public class Job { [Key, Column(Order = 0)] public int JobNumber { get; set; } [Key, Column(Order = 1)] public int VersionNumber { get; set; } public virtual User OwnedBy { get; set; } } and [Table("Usernames")] public class User { [Key] public string Username { get; set; } public string EmailAddress { get; set; } public bool IsAdministrator { get; set; } } And I have my DbContext class exposing those as IDbSet I can query my users, but as soon as I added the OwnedBy field to the Job class I began getting this error in all my tests for the Jobs: Invalid column name 'UserUsername'. I want this to behave like NHibernate's many-to-one, whereas I think EF4 is treating it as a complex type. How should this be done?

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  • Filter list as a parameter in a compiled query

    - by JK
    I have the following compiled query that I want to return a list of "groups" that don't have a "GroupID" that's contained in a filtered list: CompiledQuery.Compile(ConfigEntities contexty, List list) = from c in context.Groups where (!csList.Contains(c.GroupID)) select c).ToList() However I'm getting the following run-time error: The specified parameter 'categories' of type 'System.Collections.Generic.List`1[[System.Int32, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c261364e126]]' is not valid. Only scalar parameters (such as Int32, Decimal, and Guid) are supported. Any ideas?

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  • Need help converting SQL to EF4 please

    - by Ken Eldridge
    I need help converting this SQL statement, into EF4: Select Posts.PostID, Post, Comment from Posts left join Comments on posts.PostID = Comments.PostID Where CommentID not in ( Select PostID from Votes where VoteTypeID = 4 --4 = flagged comment type ) In my database, the Votes table stores either the PostID of reported posts, or CommentID of reported comments in the column Votes.PostID Thanks in advance!

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  • convert a sql statement to class?

    - by walter
    Is there a tool or code to convert a sql statement to class? Something like: Dim sqlText = "SELECT CustomerID, Name, Address, City FROM dbo.Customer WHERE CustomerID = 1" Dim obj As New ***SqlStatementTool***(sqlText) obj.GetTables() 'Will Return Tables in sqlText obj.GetWheres() 'Will Return conditions in sqltext obj.GetParameters() 'will return parameters in sqltext

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  • Linq - How to collect Anonymous Type as Result for a Function

    - by GibboK
    I use c# 4 asp.net and EF 4. I'm precompiling a query, the result should be a collection of Anonymous Type. At the moment I use this code. public static readonly Func<CmsConnectionStringEntityDataModel, string, dynamic> queryContentsList = CompiledQuery.Compile<CmsConnectionStringEntityDataModel, string, dynamic> ( (ctx, TypeContent) => ctx.CmsContents.Where(c => c.TypeContent == TypeContent & c.IsPublished == true & c.IsDeleted == false) .Select(cnt => new { cnt.Title, cnt.TitleUrl, cnt.ContentId, cnt.TypeContent, cnt.Summary } ) .OrderByDescending(c => c.ContentId)); I suspect the RETURN for the FUNCTION Dynamic does not work properly and I get this error Sequence contains more than one element enter code here. I suppose I need to return for my function a Collection of Anonymous Types... Do you have any idea how to do it? What I'm doing wrong? Please post a sample of code thanks! Update: public class ConcTypeContents { public string Title { get; set; } public string TitleUrl { get; set; } public int ContentId { get; set; } public string TypeContent { get; set; } public string Summary { get; set; } } public static readonly Func<CmsConnectionStringEntityDataModel, string, ConcTypeContents> queryContentsList = CompiledQuery.Compile<CmsConnectionStringEntityDataModel, string, ConcTypeContents>( (ctx, TypeContent) => ctx.CmsContents.Where(c => c.TypeContent == TypeContent & c.IsPublished == true & c.IsDeleted == false) .Select(cnt => new ConcTypeContents { cnt.Title, cnt.TitleUrl, cnt.ContentId, cnt.TypeContent, cnt.Summary }).OrderByDescending(c => c.ContentId));

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  • EntityFramework gives IDisposable error

    - by Snoop Dogg
    I use EF for the back-end DataLayer in my asp.net websites. I create a class library and add the Model in it, reference it and use it from the ASP.NET Website. But this time, I generated the model from database but it seems does not implement IDisposable, and the methods I used to see are not there. DeleteObject , SaveChanges etc. There are only Two tables in the DB and the Model was generated with only the TableSets and two methods AddToTableSet ... Had anybody encountered such a problem?

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  • Arranging VS2008 generated LinqToSql/EntityFramework data models/contexts in assemblies.

    - by JMSA
    What pattern should I use for data-access in case of VS2008 generated L2s or EF DataModels? Repository-pattern or what? As we know VS2008 generates Data-Models and DataContexts/ObjectContexts in the same file, then, how should I arrange my VS2008 assemblies in my VS2008 solution to achieve a layered design? If I use repository pattern, how should I arrange my assemblies in the VS2008 solution (as Data-Models and Data/Object-Contexts are stored in the same file...)? Any web/example link would be appreciated.

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  • ASP.net MVC3 entities, don't know how to count

    - by Spedax
    I have 2 tables, 1 with countries, 1 with states. The states table has a column with Population. I'm using entities and I have created a List of states for the countries public class TblCountries { //Entities for my table country ... public List<tblStates> States { get; set; } } So now I can for example List all the states that belong to a country. Now what I want to do is count the population, so I can show the population that of an entire country. I tried using in my view @foreach (var item in Model.Countries) { @Html.DisplayFor(modelItem => item.States.Count<population>) } But this doesn't work, anyone know how to do this? Thanks in advanced!

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  • update table with information from IDirectory

    - by sue
    I have a table with 4 columns, LoginID, LastName, FirstName, Email. The data for LoginID was populated from an other table. I have to write a small routine to update this table, by sending in the LoginID and with help of IDirectory routines, get the Lastname, firstname and email. This is what i'm attempting to do, but getting confused with the right syntax. using (TSADRequestEntities context = UnityHelper.Resolve()) { var fpvalues = context.FOCALPOINTs.ToList(); foreach (var item in fpvalues) { IEnumerable<UserInfo> query = UnityHelper.Resolve<IUserDirectory>().Search(item.LoginID); //Here, FocalPoint is the table that has the loginID and the other fields //I need to update. the query shld now hv info on lastname etc..how do I //retrieve that value and update the table? } }

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  • How do I make this Query against EF Efficient?

    - by dudeNumber4
    Using EF4. Assume I have this: IQueryable<ParentEntity> qry = myRepository.GetParentEntities(); Int32 n = 1; What I want to do is this, but EF can't compare against null. qry.Where( parent => parent.Children.Where( child => child.IntCol == n ) != null ) What works is this, but the SQL it produces (as you would imagine) is pretty inefficient: qry.Where( parent => parent.Children.Where( child => child.IntCol == n ).FirstOrDefault().IntCol == n ) How can I do something like the first comparison to null that won't be generating nested queries and so forth?

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  • EF recovery from invalidoperationexception caused by server being down

    - by Jonn
    I had a windows service relying on EF, and it was running fine until the server went down. The problem was after the server went up again, it didn't fix itself and still threw the error: INTERNAL ERROR: Execution of the command requires an open and available connection. The connection's current state is broken. Not being very proficient in EF I'm not aware of how I could recover from such a scenario, and why it occurred in the first place? Anyone had this happen before?

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  • Return nullable datetime from scalar, stored procedure

    - by molgan
    Hello I have a function that returns a date from a stored procedure, and it all works great til the value is NULL, how can I fix this so it works with null aswell? public DateTime? GetSomteDate(int SomeID) { DateTime? LimitDate= null; if (_entities.Connection.State == System.Data.ConnectionState.Closed) _entities.Connection.Open(); using (EntityCommand c = new EntityCommand("MyEntities.GetSomeDate", (EntityConnection)this._entities.Connection)) { c.CommandType = System.Data.CommandType.StoredProcedure; EntityParameter paramSomeID = new EntityParameter("SomeID", System.Data.DbType.Int32); paramSomeID.Direction = System.Data.ParameterDirection.Input; paramSomeID.Value = SomeID; c.Parameters.Add(paramSomeID); var x = c.ExecuteScalar(); if (x != null) LimitDate = (DateTime)x; return LimitDate.Value; }; }

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  • LinkDemand error on webserver when using TrackSource

    - by robertpnl
    Hi, On a webserver (shared hosting provider) I published a website with a ADO.Net Framework model in use with MySql Connector 6.3.1. When I request a page, a Security Exception will be happen with this error messages: "LinkDemand The type of the first permission that failed was: System.Security.Permissions.SecurityPermission The Zone of the assembly that failed was: MyComputer ". This exception raised when code collect the listeners of a tracksource: public class MySqlTrace { private static TraceSource source = new TraceSource("mysql"); static MySqlTrace() { foreach (TraceListener listener in source.Listeners) // <-- Exception throw here { // ... } } } The web.config doesn't have any trace data or system.diagnostics. My question is, why will a get a LinkDemand security exception during collecting the source listeners. What can maybe be wrong in here?

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  • Problem with connectionstring and entityframework

    - by Masna
    Hello, I have a database (sql 2008 mdf file), a class library project with an edmx file, created with the wizard. So the connection string is also made by the wizard. This project is on a teamfoundation server. I can use all the wizard made objects when coding. But when i run the program and I try to make an entityContainerName, the program crashes and gives this error: The specified named connection is either not found in the configuration, not intended to be used with the EntityClient provider, or not valid. on this line: public TestEntities() : base("name=TestEntities", "TestEntities") How can I solve this problem or what am I doing wrong?

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