9/27/2023 0 Comments Ef does not execute delete command![]() ![]() This approach entails relatively few lines of supporting code and yields a considerable payoff when using EF Core to retrieve complex results. We applied a simple, yet clever and powerful, solution to return a non-database entity from a stored procedure. Returning to our example query, we can use a simple command to return the department and other data associated with the first employee in our database: var employees = dbContext.SP_GetEmployeesWithDepartment(1) Our DbContext file is now ready to call a stored procedure and return a complex type result set, and our code is complete. Public partial class EFCoreSPContext : DbContext To keep EF Core’s scaffolding tools from modifying our custom code, we’ll add our result model to EFCoreSPContext.SP.cs, a partial C# class: using Such an extension is supported with partial classes and-specifically-by using an OnModelCreatingPartial method. EF provides an elegant approach to extending an application’s data model. We are ready to incorporate the result model into our application’s EF Core DbContext file. Step 2: Include the Model in the DbContext File With the result type defined, we move on to updating our EF model. This command displays the stored procedure’s columns and associated type list. Using Microsoft SQL Server as the database server, we can explicitly verify the SP result column types by executing the sp_describe_first_result_set command: EXEC sp_describe_first_result_set N'.' Step 1: Create a Stored Procedure Result Set Modelįirst, we’ll create a file called GetEmployeesWithDepartment_Result.cs and define the structure for our complex return type: public class GetEmployeesWithDepartment_Result Note: Before you proceed, scaffold your database using the Scaffold-DbContext command in the Package Manager Console or the dotnet ef dbcontext scaffold command in. We would like to execute this SP from our C# code, so let’s configure EF Core to support calling GetEmployeesWithDepartment as a parameterized SP. >= say we want to determine the department associated with the first employee listed in a simple test database (in our example, the first employee listed is John in Engineering). Our SP returns the Id value and all of its associated information, such as the employee’s Department and Name values: CREATE OR ALTER PROCEDURE INT Now let’s look at GetEmployeesWithDepartment, an SP that returns an Employee table row matching the input parameter Employee.Id. The ordinal relationships between these tables are: Relationships = Employee(1) : Department(1) and Department(1) : Employees(N) It also references the Department table from the Employee.DepartmentId field connected to the Department table’s Id column. The Employee table references itself through a foreign key from its ManagerId field. Let's consider GetEmployeesWithDepartment, a stored procedure that returns a complex result containing information from two related database tables, Employee and Department: A Hypothetical Stored Procedure With a Complex Result We’ll look at an example stored procedure to see how a few simple adjustments can overcome EF Core’s constraints. NET language that supports EF Core, provided the utility code is translated into that language. NET, Microsoft SQL Server, and EF Core together. We can get around these restrictions by using C#. Make create, update, and delete operations unavailable.Cannot return a complex type in response to a JOIN command.Restrict a stored procedure’s result to an Entity type.This is due to limitations in EF Core’s out-of-the-box solution that: Microsoft’s Entity Framework (EF) Core can be used to map or import SPs as functions but, unfortunately, EF Core doesn’t natively support the retrieval of complex results from stored procedures. NET developers often need to call a database stored procedure (SP) from their C# server layer. ![]()
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