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For some reason the .NETCore designers did not think, that developers want to follow best practices by separating the data layer from the presentation layer. The Entity framework out of the box only works if the database is accessed from the main application project. When we try to reverse engineer a PostgreSQL database from a …
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When you use the Microsoft .NET Entity framework to access a MySql database, the autogenerated code throws an error when you try to insert a row into the database with context.MY_TABLE.Add(MY_OBJECT); Server Error in ‘/’ Application. Procedure or function ‘`…_Insert`’ cannot be found in database ‘`…`’. Description: An unhandled exception occurred during the execution of …
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Two-tier applications separate the presentation layer and the data layer, and all database access related objects are located in the data-tier. When the application runs, the config file of the main project is read. In web applications, it is the web.config, in console applications the app.config file. When you get the following runtime exception Exception thrown: ‘System.InvalidOperationException’ in …
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When I made changes to the web.config file of an ASP.Net C# application, I have accidentally deleted a comma, and I started to get the runtime error message: The given assembly name or codebase was invalid. (Exception from HRESULT: 0x80131047) Make sure all necessary commas are there in the config files, Visual Studio does not …
Visual Studio 2017 has many project type options, and not all of them support the Entity Framework user interface to generate the Entity Framework Data Model (EDMX) file. If you create an ASP.NET Web Application(.NET Framework) you can add the EDMX file to it. The .NET Core projects do not support the Entity Framework Data Model …
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When a database table has composite keys (multiple columns are in the key) you cannot use the usual key definition [Key] [Display(Name = “UserId”)] public string UserId { get; set; } [Key] [Display(Name = “RoleId”)] public string RoleId { get; set; } When you run the application you get the error message: {“error”:”Entity type ‘AspNetUserRoles’ has composite …
It is not recommended to execute Entity Framework migration scripts in production, It is important that you execute all SQL steps manually on the production database section-by-section to immediately see the result and be able to recover in case a destructive action goes wrong. The Visual Studio .NET application templates contain Entity Framework migration scripts to …
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The .NET Core Entity framework makes database access easy. When you auto-generate a Razor page in a .NET web application to edit a data row, the scaffolding places controls on the page for every column. There are columns in most of the tables that we don’t want to display or edit, like keys, checksums, password …
When you move your Visual Studio solution to another workstation you may encounter the following error message: System.Data.Entity.Core.MappingException was unhandled by user code HResult=-2146232032 Message=Schema specified is not valid. Errors: : error 2062: No mapping specified for instances of the EntitySet and AssociationSet in the EntityContainer … Source=EntityFramework In this case it may help if …
When one of the projects in your solution is referencing the Entity Framework to access a database the Entity Framework NuGet package is added to that project. In the Visual Studio IDE your application may work fine, but when you deploy it to the test or production server the following error message may appear: Exception …