如何通过 asp.net 项目中的 Seed 传递 FK 的值

Posted 2023-02-16

【中文标题】如何通过 asp.net 项目中的 Seed 传递 FK 的值

【英文标题】：How do I pass the value of the FK through the Seed in asp.net project

【发布时间】：2021-12-13 12:16:22

【问题描述】：

我使用种子将默认数据输入数据库，但我遇到了一个问题，即FK， 如何毫无问题地将 FK 的值传递给两个表？

运行程序时出现此错误： SqlException：INSERT 语句与 FOREIGN KEY 约束“FK_AspNetUsers_Departments_DepartmentId”冲突。数据库“HRS.WEB1”、表“dbo.Departments”、“Id”列中发生冲突。 声明已终止。

 public static class DbSeeder
            
                public static IHost SeedDb(this IHost webHost)
                
                    using var scope = webHost.Services.CreateScope();
                    try
                    
                        var context = scope.ServiceProvider.GetRequiredService<HRSDbContext>();
                        var userManager = scope.ServiceProvider.GetRequiredService<UserManager<Employee>>();
                        context.SeedDepartment().Wait();
                        userManager.SeedEmployee().Wait();
        
                    
                    catch (Exception ex)
                    
                        Console.WriteLine(ex.Message);
                        throw;
                    
                    return webHost;
                
        
                public static async Task SeedDepartment(this HRSDbContext _db)
                
                    if (await _db.Departments.AnyAsync())
                    
                        return;
                    
        
                    var departments = new List<Department>();
        
                    var department = new Department();
                    department.Name = "A1";
                    department.Id = 1;
                    department.CreatedAt = DateTime.Now;
        
                    var department2 = new Department();
                    department2.Name = "A2";
                    department2.Id = 2;
                    department2.CreatedAt = DateTime.Now;
        
                    departments.Add(department);
                    departments.Add(department2);
        
                    await _db.Departments.AddRangeAsync(departments);
                    await _db.SaveChangesAsync();
                
        
                public static async Task SeedEmployee(this UserManager<Employee> userManger)
                
                    if (await userManger.Users.AnyAsync())
                    
                        return;
                    
                    var user = new Employee();
                    user.FullName = "System Developer";
                    user.UserName = "[e-mail]";
                    user.Email = "[e-mail]";
                    user.CreatedAt = DateTime.Now;
        
                    await userManger.CreateAsync(user, "Admin111$$");
                
        
        
            

【问题讨论】：

那里是什么关系，员工需要部门密钥吗？

是的，员工需要部门密钥，关系是一对多

好吧，当您为员工播种时，您不会传递 DepartmentId。

这是我面临的问题，当我为员工播种时，我不知道如何传递 DepartmentId ！！

【参考方案1】：

有多种方法可以做到这一点，我不知道你模型的确切结构，但无论如何日志应该是相同的：

第一 - 硬值：

public static async Task SeedEmployee(this UserManager<Employee> userManger)
            
                if (await userManger.Users.AnyAsync())
                
                    return;
                
                var user = new Employee();
                user.FullName = "System Developer";
                user.UserName = "[e-mail]";
                user.Email = "[e-mail]";
                user.CreatedAt = DateTime.Now;
                user.DepartmentId = 1; //here
    
                await userManger.CreateAsync(user, "Admin111$$");
            

第二 - 返回您添加的部门，然后将其作为参数传递：

public static IHost SeedDb(this IHost webHost)
            
                using var scope = webHost.Services.CreateScope();
                try
                
                    var context = scope.ServiceProvider.GetRequiredService<HRSDbContext>();
                    var userManager = scope.ServiceProvider.GetRequiredService<UserManager<Employee>>();
                    var departments = context.SeedDepartment().Wait();
                    userManager.SeedEmployee(departments.First().Id ).Wait();
    
                
                catch (Exception ex)
                
                    Console.WriteLine(ex.Message);
                    throw;
                
                return webHost;
            
    
            public static async Task<IEnumerable<Department>> SeedDepartment(this HRSDbContext _db)
            
                var _departments = await _db.Departments.AllAsync()
                if (_departments != null)
                
                    return _departments;
                
    
                var departments = new List<Department>();
    
                var department = new Department();
                department.Name = "A1";
                department.Id = 1;
                department.CreatedAt = DateTime.Now;
    
                var department2 = new Department();
                department2.Name = "A2";
                department2.Id = 2;
                department2.CreatedAt = DateTime.Now;
    
                departments.Add(department);
                departments.Add(department2);
    
                await _db.Departments.AddRangeAsync(departments);
                await _db.SaveChangesAsync();

                return departments;
            
    
            public static async Task SeedEmployee(this UserManager<Employee> userManger, int departmentId)
            
                if (await userManger.Users.AnyAsync())
                
                    return;
                
                var user = new Employee();
                user.FullName = "System Developer";
                user.UserName = "[e-mail]";
                user.Email = "[e-mail]";
                user.CreatedAt = DateTime.Now;
                user.DepartmentId = departmentId;
    
                await userManger.CreateAsync(user, "Admin111$$");
            

【讨论】：

第二个答案比较准确，不过需要修改一下，谢谢老哥

我的代码需要修改，而不是你的答案