entity-framework-6

问题 I want to create ADO.NET entity data model - database first (.edmx file) with EntityFramework6.Npgsql but it's error. I have installed: - EntityFramework6.Npgsql (version 6.3 newest) - Npgsql (version 4.1.1 newest) - EntityFramework (version 6.3 newest) I created it before, but I don't know why now! Please help me.... 回答1: This is a known issue that is already tracked on github In the meantime for those having issues with the latest version of the VSIX (4.1.1.2), please downgrade back to 4.0

问题 I develop web application with Entity framework 6. I have a model Folder that contains a list of Letter object. My letter object: public class Letter { [Key] public int Id [ForeignKey("Folder")] public int FolderId {get; set;} public virtual Folder Folder {get; set;} } I have 2 dbsets in my DbContext: DbSet<Folder> DbSet<Letter> My question is what happens when I add a new Letter? If I later on fetch the folder I added the letters, will those letters be contained in the folder's letters list?

问题 I have JetBrains Rider 2018.3 on macOS Mojave. I created an ASP.NET MVC project, installed entity framework 6.2. I added the connection string to web.config. But, I don't know how to configure app.config. I want to enable-migrations for this project to connect to the Microsoft SQL Server. I googled it and found this link Entity Framework Support in Rider. However, I am not able to find Tools | Entity Framework | Initial setup . I was wondering if you could help me to solve this issue. 回答1:

问题 On trying to resolve my service class, I'm getting an error that DbContext cannot be constructed because it's an abstract class. The error message is here: Unity.Exceptions.ResolutionFailedException: 'Resolution of the dependency failed, type = 'MyService.MyClass', name = '(none)'. Exception occurred while: while resolving. Exception is: InvalidOperationException - The current type, System.Data.Common.DbConnection, is an abstract class and cannot be constructed. Are you missing a type mapping

问题 I defined a DataObject as: public class SensorType : EntityData { //PKs public string CompanyId { get; set; } public string ServiceId { get; set; } public string Type { get; set; } } And used fluent API to make CompanyId and ServiceId a composite key: modelBuilder.Entity<SensorType>() .HasKey(t => new { t.CompanyId, t.ServiceId }); //No autogeneration of PKs modelBuilder.Entity<SensorType>().Property(t => t.ServiceId) .HasDatabaseGeneratedOption(System.ComponentModel.DataAnnotations.Schema

问题 I defined a DataObject as: public class SensorType : EntityData { //PKs public string CompanyId { get; set; } public string ServiceId { get; set; } public string Type { get; set; } } And used fluent API to make CompanyId and ServiceId a composite key: modelBuilder.Entity<SensorType>() .HasKey(t => new { t.CompanyId, t.ServiceId }); //No autogeneration of PKs modelBuilder.Entity<SensorType>().Property(t => t.ServiceId) .HasDatabaseGeneratedOption(System.ComponentModel.DataAnnotations.Schema

问题 I am trying to implement a simple self referencing relationship with EF 6.1.2 Code First. public class Branch { [Key] public int Id { get; set; } [Required] public string Name { get; set; } public int? ParentId { get; set; } [ForeignKey("ParentId")] public virtual Branch Parent { get; set; } public ICollection<Branch> Children { get; set; } // direct successors } In my application I have exactly one root branch. And except for this single root branch, every branch has exactly one parent (the

问题 I am trying to implement a simple self referencing relationship with EF 6.1.2 Code First. public class Branch { [Key] public int Id { get; set; } [Required] public string Name { get; set; } public int? ParentId { get; set; } [ForeignKey("ParentId")] public virtual Branch Parent { get; set; } public ICollection<Branch> Children { get; set; } // direct successors } In my application I have exactly one root branch. And except for this single root branch, every branch has exactly one parent (the

问题 I am trying to implement a simple self referencing relationship with EF 6.1.2 Code First. public class Branch { [Key] public int Id { get; set; } [Required] public string Name { get; set; } public int? ParentId { get; set; } [ForeignKey("ParentId")] public virtual Branch Parent { get; set; } public ICollection<Branch> Children { get; set; } // direct successors } In my application I have exactly one root branch. And except for this single root branch, every branch has exactly one parent (the

问题 I have a simple Oracle stored procedure that gets three parameters passed in, and has one output parameter: CREATE OR REPLACE PROCEDURE RA.RA_REGISTERASSET ( INPROJECTNAME IN VARCHAR2 ,INCOUNTRYCODE IN VARCHAR2 ,INLOCATION IN VARCHAR2 ,OUTASSETREGISTERED OUT VARCHAR2 ) AS BEGIN SELECT INPROJECTNAME || ', ' || INLOCATION || ', ' || INCOUNTRYCODE INTO OUTASSETREGISTERED FROM DUAL; END RA_REGISTERASSET; I am trying to use Entity Framework 6.1 to get back the OutAssetRegistered value, however, I