SqlException：无法将值 NULL 插入列“CarId”、表“AutoServiceDb.dbo.ServiceOrders”；列不允许空值。插入失败

Posted 2023-05-07

【中文标题】SqlException：无法将值 NULL 插入列“CarId”、表“AutoServiceDb.dbo.ServiceOrders”；列不允许空值。插入失败

【英文标题】：SqlException: Cannot insert the value NULL into column 'CarId', table 'AutoServiceDb.dbo.ServiceOrders'; column does not allow nulls. INSERT fails

【发布时间】：2020-02-24 11:02:02

【问题描述】：

当我想添加一个新条目时，它会抛出一个错误

SqlException：无法将值 NULL 插入到列“CarId”、表“AutoServiceDb.dbo.ServiceOrders”中；列不允许空值。插入失败。声明已终止。

以下是控制器代码、DTO、服务和 Blazor 控制器

using System;
using Microsoft.AspNetCore.Mvc;
using AutoService.Domain.Entities;
using AutoService.Application.Interfaces;
using System.Threading.Tasks;
using AutoService.API.Models;
using AutoMapper;
using AutoService.Application.DTOs;

namespace AutoService.API.Controllers

    [ApiController]
    [Route("[controller]")]

    public class ServiceOrderController : ControllerBase
    
        private readonly IServiceOrderService _serviceOrder;
        private readonly IMapper _mapper;
        public ServiceOrderController(IServiceOrderService serviceOrder , IMapper mapper)
        
            _serviceOrder = serviceOrder;
            _mapper = mapper;
        

        [HttpPost("scheduleservice")]
        public IActionResult ScheduleService([FromBody] ScheaduleViewModel model)
        

            var order = _mapper.Map<ScheaduleViewModel, OrderDTO>(model);

            var result = _serviceOrder.ScheduleService(order);
            if (result == null) return BadRequest();
            return Ok(result);
        

        [HttpGet]
        public async Task<IActionResult> GetService()
        
            var result = await _serviceOrder.GetServicesAsync();
            return Ok(result);
        

    

订购DTO

using System;
using System.Collections.Generic;
using System.Text;

namespace AutoService.Application.DTOs

    public class OrderDTO
    
        //create
        public string ClientName  get; set; 
        public string ClientPhone  get; set; 
        public string CarMake  get; set; 
        public string CarModel  get; set; 
        public string CarPlate  get; set; 
        public string CarColor  get; set; 
        public DateTime ScheduledDate  get; set; 
    

服务

using AutoService.Application.DTOs;
using AutoService.Application.Interfaces;
using AutoService.Domain.Entities;
using AutoService.Infrastructure.Context;
using Microsoft.EntityFrameworkCore;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;


namespace AutoService.Application.Services

    public class ServiceOrderService : IServiceOrderService
    
        private readonly ServicingContext _context;
        public ServiceOrderService(ServicingContext context)
        
            _context = context;
        
        public async Task CreateService(ServiceOrder serviceOrder)
        
            _context.ServiceOrders.Add(serviceOrder);
            await _context.SaveChangesAsync();
        
        public  async Task<List<ServiceOrder>> GetServicesAsync()
        
        var result = await _context.ServiceOrders
        .Include(c => c.Client)
        .Include(k => k.Car)

        .ToListAsync();

        return result;
        
        public ServiceOrder ScheduleService(OrderDTO orderDTO)
        
            var client = _context.Clients.FirstOrDefault(c => c.FirstName == orderDTO.ClientName);
            if (client == null)
            
                _context.Clients.Add(new Client
                
                    FirstName = orderDTO.ClientName,
                    PhoneNumber = orderDTO.ClientPhone
                );

            

            var car = _context.Cars.Where((c => c.Makes == orderDTO.CarMake && c.Model == orderDTO.CarModel && c.Color == orderDTO.CarColor && c.LicensePlate == orderDTO.CarPlate)).FirstOrDefault();
            if (car == null)
            
                var entity = _context.Cars.Add(new Car
                
                    Makes = orderDTO.CarMake,
                    Model = orderDTO.CarModel,
                    Color = orderDTO.CarColor,
                    LicensePlate = orderDTO.CarPlate

                );

            

            var serviceOrder = _context.Add(new ServiceOrder
            
                Client = client,
                Car = car,
                ScheduledTime = orderDTO.ScheduledDate,
                CreationDate = DateTime.UtcNow

            );

            _context.SaveChanges();


            return serviceOrder.Entity;

        
    

Blazor 页面添加新订单

@page "/addServiceOrder"

@using System.Text.Json
@using System.Text
@using AutoService.API.Models



<link rel="stylesheet" href="css/bootstrap/bootstrap.min.css" />
<link href="css/site.css" rel="stylesheet" />
<form method="post">
    <table>
        <label ></label>
        <tr>
            <td>Client name:</td>
            <td><input @bind="ClientName" /></td>
        </tr>
        <tr>
            <td>Client phone</td>
            <td><input @bind="ClientPhone" /></td>
        </tr>
        <tr>
            <td>Car model</td>
            <td><input @bind="CarModel" /></td>
        </tr>
        <tr>
            <td>Car make</td>
            <td><input @bind="CarMake" /></td>
        </tr>
        <tr>
            <td>Car plate</td>
            <td><input @bind="CarPlate" /></td>
        </tr>
        <tr>
            <td>Car color</td>
            <td><input @bind="CarColor" /></td>
        </tr>
        <tr>
            <td>Scheduled date</td>
            <td><input @bind="ScheduledDate" /></td>
        </tr>
    </table>
    <a class="btn btn-secondary" href="serviceOrder">Back</a>
    <button type="button" class="btn btn-primary" @onclick="AddNewOrder">&#10004;Add</button> @Alert
    <p />
</form>
<h1>Add service order</h1>
<p />


@code 
    @inject IHttpClientFactory clientFactory;
    protected string ClientName  get; set; 
    protected string ClientPhone  get; set; 
    protected string CarMake  get; set; 
    protected string CarModel  get; set; 
    protected string CarPlate  get; set; 
    protected string CarColor  get; set; 
    protected DateTime ScheduledDate  get; set; 
    protected string Alert  get; set; 


    protected async Task AddNewOrder()
    
        Alert = " ";
        if (ClientName == string.Empty || ClientPhone == string.Empty || CarMake == string.Empty || CarModel == string.Empty || CarPlate == string.Empty || CarColor == string.Empty || ScheduledDate == DateTime.Now)
        
            Alert = "Fill all fields!";
            return;

        
        Alert = "Added new order";
        var _client = clientFactory.CreateClient();
        ScheaduleViewModel _newOrder = new ScheaduleViewModel  ClientName = ClientName, ClientPhone = ClientPhone, CarMake = CarMake, CarModel = CarModel, CarPlate = CarPlate, CarColor = CarColor, ScheduledDate = ScheduledDate, ;
        var _content = new StringContent(JsonSerializer.Serialize(_newOrder), Encoding.UTF8, "application/json");
        await _client.PostAsync("https://localhost:5001/ServiceOrder/scheduleservice", _content);

    

Blazor 页面“ServiceOrder”

@page "/serviceOrder"
@using AutoService.Domain.Entities
@using System.Text.Json




<h1>Service order</h1>
<p />
<a class="btn btn-primary" href="addServiceOrder">&#10002;Add order</a>

<p />
@if (ServiceOrdersList == null)

    <div>Loading...</div>

else


    <table class="table">
        <thead>
            <tr>
                <td>Id</td>
                <td>Firs name owner</td>
                <td>Car model</td>
                <td>Creation </td>
                <td>Scheduled time</td>

            </tr>
        </thead>
        <tbody>

            @foreach (var serviceOrder in ServiceOrdersList)
            
                <tr>
                    <td>@serviceOrder.Id</td>
                    <td>@serviceOrder.Client.FirstName</td>
                    <td>@serviceOrder.Car.Model</td>
                    <td>@serviceOrder.CreationDate</td>
                    <td>@serviceOrder.ScheduledTime</td>

                </tr>

            

        </tbody>
    </table>


@code 

    public List<ServiceOrder> ServiceOrdersList  get; set; 

    @inject IHttpClientFactory _clientFactory;
    protected string info;

    protected override async Task OnInitializedAsync()
    

        var client = _clientFactory.CreateClient();
        var result = await client.GetAsync("https://localhost:5001/serviceOrder");

        info = await result.Content.ReadAsStringAsync();
        var options = new JsonSerializerOptions
        
            IgnoreNullValues = true,
            PropertyNameCaseInsensitive = true
        ;
        ServiceOrdersList = JsonSerializer.Deserialize<List<ServiceOrder>>(info, options);



    

enter image description here

车型

using System;
using System.Collections.Generic;
using System.Text;

namespace AutoService.Domain.Entities

    public class Car
    
        public int Id  get; set; 
        public string Makes  get; set; 
        public string Model  get; set; 
        public string Color  get; set; 
        public string LicensePlate  get; set; 



    

【问题讨论】：

错误告诉你问题所在。不明白怎么办？

上面明确写着CardId不能为空。

你能把Car模型添加到问题中吗！

如果您的 CarId 应该是身份列，请检查此答案 - ***.com/questions/10013313/…

ServiceOrder.Car 导航属性是否标记为虚拟？

【参考方案1】：

您似乎没有将新的“实体”分配给您尝试创建的“汽车”对象...

var car = _context.Cars.Where(...).FirstOrDefault();
if (car == null)

    var entity = _context.Cars.Add(new Car
    
       ...
    );


var serviceOrder = _context.Add(new ServiceOrder

   Client = client,
   Car = car, // <-- 'car' is still null when you assign it's value to the service order
   ...

尝试添加如下内容：

var car = _context.Cars.Where(...).FirstOrDefault();
if (car == null)

    car = new Car // Assign the new car to the null car variable.
    
      ...
    ;

    _context.Cars.Add(car); // Then add it to the context.

由于“ServiceOrder.Car”属性在尝试将其插入 SQL 时为空，因此数据库会尝试将 NULL 插入 CarId。