entity-framework-6

问题 i am new to EF ... getting this error while adding another edmx in same project using same connection string . this is my connection string <add name="REFLECTIONDBEntities" connectionString="metadata=res://*/;provider=System.Data.SqlClient;provider connection string="data source=SERVER;initial catalog=REFLECTIONDB;persist security info=True;user id=sa;password=Sqlsa123;multipleactiveresultsets=True;application name=EntityFramework"" /> 回答1: Same connection Strings Names are not allowed, you

问题 How can I resolve this error? I have added the Entity Framework 6.1.3 from this link: Download EntityFramework 6.1.3 for Visual Studio 2013 (after uninstalling and re-installing it again and again) Now that it has been added and in the project created a .emdx file using ADO.NET Entity Data Model . When I try to build it, the following error pops: EntityFramework.dll not found (after Compilation) 回答1: Don't uninstall the Visual Studio. Installing the Entity Framework 6 Tools for Visual Studio,

问题 That's my basic ( Database First ) diagram on SQL Server : When I Update Model from Database using Entity Framework (6.x) within my MVC application, I expect Users got this property: public virtual ICollection<Role> Roles { get; set; } As well Roles with: public virtual ICollection<User> Users { get; set; } But instead I got: public virtual ICollection<UsersRoles> UsersRoles { get; set; } public virtual ICollection<UsersRoles> UsersRoles { get; set; } Where am I wrong? 回答1: Your design is

问题 I'm in a Xamarin.Forms project (C#) using Sqlite and EF plug-in (Microsoft.Enttityframeworkcore.sqlite). What happens depends: Scenario 1: I use "Database.EnsureDeletedAsync" I can put data into DB within the same "using" statement and "dbContext" object, I can retrieve the data using LINQ query no errors. Scenario 2: I do not use "Database.EnsureDeletedAsync" the database already exists I can add data to it within the same "using" statement and "dbContext" object, any attempt to retrieve the

问题 I've a table like this Id MachineName ServerName TagName TagValue ValueDateTime 1 DanPac_A Daniel.Device Links.1 Poll.Registers Block 0.STR02_METER_DENSITY_(1) 93.1631400000 2018-06-04 21:08:28.720 2 DanPac_A Daniel.Device Links.1 Diagnostics.Heartbeat 1.0000000000 2018-06-04 21:08:32.717 3 DanPac_A Daniel.Device Links.1 Poll.Registers Block 0.310-TT-302_(6) 52.1062000000 2018-06-04 21:08:32.873 4 DanPac_A Daniel.Device Links.1 Poll.Registers Block 0.310-TT-302_(6) 52.1062000000 2018-06-04 21

问题 I've a table like this Id MachineName ServerName TagName TagValue ValueDateTime 1 DanPac_A Daniel.Device Links.1 Poll.Registers Block 0.STR02_METER_DENSITY_(1) 93.1631400000 2018-06-04 21:08:28.720 2 DanPac_A Daniel.Device Links.1 Diagnostics.Heartbeat 1.0000000000 2018-06-04 21:08:32.717 3 DanPac_A Daniel.Device Links.1 Poll.Registers Block 0.310-TT-302_(6) 52.1062000000 2018-06-04 21:08:32.873 4 DanPac_A Daniel.Device Links.1 Poll.Registers Block 0.310-TT-302_(6) 52.1062000000 2018-06-04 21

问题 I'm trying to get a test project running using MySQL and EF6 using Visual Studio 2019 Community Preview for Mac. I am using the Web Application (Model-View-Controller) / .NET Core -> App template as a starting point as well as the MyWind database. I'm getting the following exception and am not sure how to proceed. TypeLoadException: Could not load type 'System.ComponentModel.DataAnnotations.AssociatedMetadataTypeTypeDescriptionProvider' from assembly 'System.ComponentModel.DataAnnotations,

问题 The question as a one liner How do I get EF to generate as part of a code first migration ALTER TABLE [DMS].[Forms] ADD CONSTRAINT [DF_DMS.Forms_Id] DEFAULT (newid()) FOR [Id] GO More detail of the problem I'm to build out a simple table to store information about forms, as it happens I already have this working for another table in my db but if I show you the code (see below) you'll realise the issue i'm hitting is more strange than it might seem ... First the working example entity: [Table(

问题 I am using Visual Studio 2013 web form application with MySql database to build a web form application but I have been unable to get passed 'Membership and Role Management'. I used a database first approach for the membership and when I try registering a new user, I get the error message below: Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

问题 I am using Visual Studio 2013 web form application with MySql database to build a web form application but I have been unable to get passed 'Membership and Role Management'. I used a database first approach for the membership and when I try registering a new user, I get the error message below: Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.