实体框架核心:"SqlNullValueException:数据为空."如何解决问题? [英] Entity Framework Core: `SqlNullValueException: Data is Null.` How to troubleshoot?

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问题描述

我在ASP.NET Core应用程序和Controller动作中使用Entity Framework Core,但我尚未对工作代码或数据库进行任何更改,但我无法确定Entity Framework Core执行的查询是什么.

控制器动作:

 [HttpGet]
// GET: Administration/Companies
public async Task<ActionResult> Index()
{
    var users = await UserManager.Users.ToListAsync();

    var companyEditVMs = await DB.Companies
    .OrderBy(company => company.CompanyId == 1 
        ? "_" + company.CompanyName 
        : company.CompanyName
    )
    Select(a => new CompanyEditVM(HttpContext, a, users.Where(b => b.CompanyId == a.CompanyId)))
    .ToListAsync();

    return View(companyEditVMs);
}
 

跟踪

 SqlNullValueException: Data is Null. This method or property cannot be called on Null values.
System.Data.SqlClient.SqlBuffer.get_String()
System.Data.SqlClient.SqlDataReader.GetString(int i)
lambda_method(Closure , DbDataReader )
Microsoft.EntityFrameworkCore.Storage.Internal.TypedRelationalValueBufferFactory.Create(DbDataReader dataReader)
Microsoft.EntityFrameworkCore.Query.Internal.AsyncQueryingEnumerable<T>+AsyncEnumerator.BufferlessMoveNext(DbContext _, bool buffer, CancellationToken cancellationToken)
Microsoft.EntityFrameworkCore.SqlServer.Storage.Internal.SqlServerExecutionStrategy.ExecuteAsync<TState, TResult>(TState state, Func<DbContext, TState, CancellationToken, Task<TResult>> operation, Func<DbContext, TState, CancellationToken, Task<ExecutionResult<TResult>>> verifySucceeded, CancellationToken cancellationToken)
Microsoft.EntityFrameworkCore.Query.Internal.AsyncQueryingEnumerable<T>+AsyncEnumerator.MoveNext(CancellationToken cancellationToken)
Microsoft.EntityFrameworkCore.Query.Internal.AsyncLinqOperatorProvider+ExceptionInterceptor<T>+EnumeratorExceptionInterceptor.MoveNext(CancellationToken cancellationToken)
System.Linq.AsyncEnumerable.Aggregate_<TSource, TAccumulate, TResult>(IAsyncEnumerable<TSource> source, TAccumulate seed, Func<TAccumulate, TSource, TAccumulate> accumulator, Func<TAccumulate, TResult> resultSelector, CancellationToken cancellationToken) in Aggregate.cs
KYC.Core.Areas.Commercial.Controllers.CompaniesController.Index() in CompaniesController.cs
-
        [HttpGet]
        // GET: Administration/Companies
        public async Task<ActionResult> Index()
        {
            var users = await UserManager.Users.ToListAsync();

            var companyEditVMs = await DB.Companies
                .OrderBy(company => company.CompanyId == 1 
                    ? "_" + company.CompanyName 
                    : company.CompanyName
                )
                .Select(a => new CompanyEditVM(HttpContext, a, users.Where(b => b.CompanyId == a.CompanyId)))
                .ToListAsync();
lambda_method(Closure , object )
Microsoft.Extensions.Internal.ObjectMethodExecutorAwaitable+Awaiter.GetResult()
Microsoft.AspNetCore.Mvc.Internal.ActionMethodExecutor+TaskOfActionResultExecutor.Execute(IActionResultTypeMapper mapper, ObjectMethodExecutor executor, object controller, object[] arguments)
System.Threading.Tasks.ValueTask<TResult>.get_Result()
 

我什至试图做var companies = await DB.Companies.ToListAsync().和我有完全一样的例外.

也许我希望能够获取由EF Core执行的查询以手动执行,以便我可以尝试找出查询出了什么问题.

我想知道可能会发生什么.尤其是因为仍然可以从数据库中获取其他实体(例如用户或国家/地区).

知道如何解决实际的潜在问题吗?

代码"中唯一实际更改的是nuget引用,我基本上升级了几乎所有内容,尽管它没有破坏代码中的引用,但似乎改变了EF Core的解释方式(荒谬的猜测).数据库.

我确实在nuget软件包更新发生并且工作正常之前将git存储库重置为该点.然后,我决定将EntityFrameworkCore从2.0.2更新到2.2.4(也尝试使用2.2.0并最终得到相同的结果),问题再次发生...不确定2.0.2和2.2之间发生了什么变化. 0触发此异常(但模型相同,只是更改了EF Core版本)...

这是实体定义,它似乎已经使用工具从数据库表/架构中自动生成:

 
    [Table("T_Companies")]
    public partial class Company : INotifyPropertyChanging, INotifyPropertyChanged
    {
        public override string ToString()
        {
            return CompanyId + " " + CompanyName;
        }

        private static PropertyChangingEventArgs emptyChangingEventArgs = new PropertyChangingEventArgs(string.Empty);

        private int _CompanyId;

        private string _CompanyName;

        private int _CompanyTypeId;

        private int _CountryId;

        private string _CompanyVatNumber;

        private string _CompanyStreetAddress;

        private string _CompanyZipCode;

        private string _CompanyCity;

        private string _ContactLastName;

        private string _ContactFirstName;

        private bool? _Active;

        private int? _AccountId;

        private string _CallbackSalt;

        private int? _UserSpaceId;

        private string _Login;

        private string _Pwd;

        private bool _IsTechnicalAccount;

        private DateTime? _StatusDate;

        private int _BankStatusCode;

        private string _PivotalAccount;

        private CompanyType _CompanyType;

        private Country _Country;

        private bool _IsKycIdSent;

        #region Extensibility Method Definitions
        partial void OnLoaded();
        partial void OnCreated();
        partial void OnCompanyIdChanging(int value);
        partial void OnCompanyIdChanged();
        partial void OnCompanyNameChanging(string value);
        partial void OnCompanyNameChanged();

        partial void OnCompanyCityChanging(string value);
        partial void OnCompanyCityChanged();
        partial void OnCompanyZipCodeChanging(string value);
        partial void OnCompanyZipCodeChanged();
        partial void OnContactLastNameChanging(string value);
        partial void OnContactLastNameChanged();
        partial void OnActiveChanging(bool? value);
        partial void OnActiveChanged();
        partial void OnCompanyTypeIdChanging(int value);
        partial void OnCompanyTypeIdChanged();
        partial void OnCountryIdChanging(int value);
        partial void OnCountryIdChanged();
        partial void OnContactFirstNameChanging(string value);
        partial void OnContactFirstNameChanged();
        partial void OnCompanyVatNumberChanging(string value);
        partial void OnCompanyVatNumberChanged();
        partial void OnCompanyStreetAddressChanged();
        partial void OnCompanyStreetAddressChanging(string value);
        partial void OnAccountIdChanging(int? value);
        partial void OnAccountIdChanged();
        partial void OnCallbackSaltChanging(string value);
        partial void OnCallbackSaltChanged();
        partial void OnUserSpaceIdChanging(int? value);
        partial void OnUserSpaceIdChanged();
        partial void OnLoginChanging(string value);
        partial void OnLoginChanged();
        partial void OnPwdChanging(string value);
        partial void OnPwdChanged();
        partial void OnIsTechnicalAccountChanging(bool value);
        partial void OnIsTechnicalAccountChanged();
        partial void OnStatusDateChanging(DateTime? value);
        partial void OnStatusDateChanged();
        partial void OnBankStatusCodeChanging(int value);
        partial void OnBankStatusCodeChanged();
        partial void OnPivotalAccountChanging(string value);
        partial void OnPivotalAccountChanged();
        partial void OnIsKycIdSentChanging(bool value);
        partial void OnIsKycIdSentChanged();

        #endregion

        public Company()
        {
            OnCreated();
        }

        [Key, Column("CompanyId"), DatabaseGenerated(DatabaseGeneratedOption.Identity)]
        public int CompanyId
        {
            get => _CompanyId;
            set
            {
                if (_CompanyId != value)
                {
                    OnCompanyIdChanging(value);
                    SendPropertyChanging();
                    _CompanyId = value;
                    SendPropertyChanged("CompanyId");
                    OnCompanyIdChanged();
                }
            }
        }

        [DataType(DataType.Text), StringLength(1024), Column("CompanyName"), Required]
        public string CompanyName
        {
            get => _CompanyName;
            set
            {
                if (_CompanyName != value)
                {
                    OnCompanyNameChanging(value);
                    SendPropertyChanging();
                    _CompanyName = value;
                    SendPropertyChanged("CompanyName");
                    OnCompanyNameChanged();
                }
            }
        }

        [Column("CompanyTypeId"), Required]
        public int CompanyTypeId
        {
            get => _CompanyTypeId;
            set
            {
                if (_CompanyTypeId != value)
                {
                    OnCompanyTypeIdChanging(value);
                    SendPropertyChanging();
                    _CompanyTypeId = value;
                    SendPropertyChanged("CompanyTypeId");
                    OnCompanyTypeIdChanged();
                }
            }
        }


        [Column("CountryId"), Required]
        public int CountryId
        {
            get => _CountryId;
            set
            {
                if (CountryId != value)
                {
                    OnCountryIdChanging(value);
                    SendPropertyChanging();
                    _CountryId = value;
                    SendPropertyChanged("CountryId");
                    OnCountryIdChanged();
                }
            }
        }


        [DataType(DataType.Text), StringLength(100), Column("CompanyCity"), Required]
        public string CompanyCity
        {
            get => _CompanyCity;
            set
            {
                if (_CompanyCity != value)
                {
                    OnCompanyCityChanging(value);
                    SendPropertyChanging();
                    _CompanyCity = value;
                    SendPropertyChanged("CompanyCity");
                    OnCompanyCityChanged();
                }
            }
        }

        [DataType(DataType.Text), StringLength(100), Column("CompanyStreetAddress"), Required]
        public string CompanyStreetAddress
        {
            get => _CompanyStreetAddress;
            set
            {
                if (_CompanyStreetAddress != value)
                {
                    OnCompanyStreetAddressChanging(value);
                    SendPropertyChanging();
                    _CompanyStreetAddress = value;
                    SendPropertyChanged("CompanyStreetAddress");
                    OnCompanyStreetAddressChanged();
                }
            }
        }

        [DataType(DataType.Text), StringLength(30), Column("CompanyVatNumber"), Required]
        public string CompanyVatNumber
        {
            get => _CompanyVatNumber;
            set
            {
                if (_CompanyVatNumber != value)
                {
                    OnCompanyVatNumberChanging(value);
                    SendPropertyChanging();
                    _CompanyVatNumber = value;
                    SendPropertyChanged("CompanyVatNumber");
                    OnCompanyVatNumberChanged();
                }
            }
        }


        [DataType(DataType.Text), StringLength(10), Column("CompanyZipCode"), Required]
        public string CompanyZipCode
        {
            get => _CompanyZipCode;
            set
            {
                if (_CompanyZipCode != value)
                {
                    OnCompanyZipCodeChanging(value);
                    SendPropertyChanging();
                    _CompanyZipCode = value;
                    SendPropertyChanged("CompanyZipCode");
                    OnCompanyZipCodeChanged();
                }
            }
        }


        [DataType(DataType.Text), StringLength(1024), Column("ContactLastName"), Required]
        public string ContactLastName
        {
            get => _ContactLastName;
            set
            {
                if (_ContactLastName != value)
                {
                    OnContactLastNameChanging(value);
                    SendPropertyChanging();
                    _ContactLastName = value;
                    SendPropertyChanged("ContactLastName");
                    OnContactLastNameChanged();
                }
            }
        }

        [DataType(DataType.Text), StringLength(1024), Column("ContactFirstName"), Required]
        public string ContactFirstName
        {
            get => _ContactFirstName;
            set
            {
                if (_ContactFirstName != value)
                {
                    OnContactFirstNameChanging(value);
                    SendPropertyChanging();
                    _ContactFirstName = value;
                    SendPropertyChanged("ContactFirstName");
                    OnContactFirstNameChanged();
                }
            }
        }

        [Column("Active"), Required]
        public bool? Active
        {
            get => _Active;
            set
            {
                if (_Active != value)
                {
                    OnActiveChanging(value);
                    SendPropertyChanging();
                    _Active = value;
                    SendPropertyChanged("Active");
                    OnActiveChanged();
                }
            }
        }

        [Column("AccountId")]
        public int? AccountId
        {
            get => _AccountId;
            set
            {
                if (_AccountId != value)
                {
                    OnAccountIdChanging(value);
                    SendPropertyChanging();
                    _AccountId = value;
                    SendPropertyChanged("AccountId");
                    OnAccountIdChanged();
                }
            }
        }

        [DataType(DataType.Text), StringLength(1024), Column("CallbackSalt")]
        public string CallbackSalt
        {
            get => _CallbackSalt;
            set
            {
                if (_CallbackSalt != value)
                {
                    OnCallbackSaltChanging(value);
                    SendPropertyChanging();
                    _CallbackSalt = value;
                    SendPropertyChanged("CallbackSalt");
                    OnCallbackSaltChanged();
                }
            }
        }

        [Column("UserSpaceId")]
        public int? UserSpaceId
        {
            get => _UserSpaceId;
            set
            {
                if (_UserSpaceId != value)
                {
                    OnUserSpaceIdChanging(value);
                    SendPropertyChanging();
                    _UserSpaceId = value;
                    SendPropertyChanged("UserSpaceId");
                    OnUserSpaceIdChanged();
                }
            }
        }

        [DataType(DataType.Text), StringLength(1024), Column("Login")]
        public string Login
        {
            get => _Login;
            set
            {
                if (_Login != value)
                {
                    OnLoginChanging(value);
                    SendPropertyChanging();
                    _Login = value;
                    SendPropertyChanged("Login");
                    OnLoginChanged();
                }
            }
        }

        [DataType(DataType.Text), StringLength(1024), Column("Pwd")]
        public string Pwd
        {
            get => _Pwd;
            set
            {
                if (_Pwd != value)
                {
                    OnPwdChanging(value);
                    SendPropertyChanging();
                    _Pwd = value;
                    SendPropertyChanged("Pwd");
                    OnPwdChanged();
                }
            }
        }

        [Column("IsTechnicalAccount"), Required]
        public bool IsTechnicalAccount
        {
            get => _IsTechnicalAccount;
            set
            {
                if (_IsTechnicalAccount != value)
                {
                    OnIsTechnicalAccountChanging(value);
                    SendPropertyChanging();
                    _IsTechnicalAccount = value;
                    SendPropertyChanged("IsTechnicalAccount");
                    OnIsTechnicalAccountChanged();
                }
            }
        }

        [DataType(DataType.DateTime), Column("StatusDate")]
        public DateTime? StatusDate
        {
            get => _StatusDate;
            set
            {
                if (_StatusDate != value)
                {
                    OnStatusDateChanging(value);
                    SendPropertyChanging();
                    _StatusDate = value;
                    SendPropertyChanged("StatusDate");
                    OnStatusDateChanged();
                }
            }
        }

        [Column("BankStatusCode")]
        public int BankStatusCode
        {
            get => _BankStatusCode;
            set
            {
                if (_BankStatusCode != value)
                {
                    OnBankStatusCodeChanging(value);
                    SendPropertyChanging();
                    _BankStatusCode = value;
                    SendPropertyChanged("BankStatusCode");
                    OnBankStatusCodeChanged();
                }
            }
        }

        [DataType(DataType.Text), StringLength(255), Column("PivotalAccount")]
        public string PivotalAccount
        {
            get => _PivotalAccount;
            set
            {
                if (_PivotalAccount != value)
                {
                    OnPivotalAccountChanging(value);
                    SendPropertyChanging();
                    _PivotalAccount = value;
                    SendPropertyChanged("PivotalAccount");
                    OnPivotalAccountChanged();
                }
            }
        }

        public List<Resultat> Resultats { get; set; }

        public CompanyType CompanyType
        {
            get => _CompanyType;
            set
            {
                var previousValue = _CompanyType;
                if (previousValue != value)
                {
                    SendPropertyChanging();
                    _CompanyType = value;
                    if (value != null)
                    {
                        CompanyTypeId = value.CompanyTypeId;
                    }
                    else
                    {
                        _CompanyTypeId = default;
                    }
                    SendPropertyChanged("CompanyType");
                }
            }
        }

        public Country Country
        {
            get => _Country;
            set
            {
                var previousValue = _Country;
                if (previousValue != value)
                {
                    SendPropertyChanging();
                    _Country = value;
                    _CountryId = value?.CountryId ?? default;
                    SendPropertyChanged("Country");
                }
            }
        }

        [Column("IsKycIdSent"), Required]
        public bool IsKycIdSent
        {
            get => _IsKycIdSent;
            set
            {
                if (_IsKycIdSent != value)
                {
                    OnIsKycIdSentChanging(value);
                    SendPropertyChanging();
                    _IsKycIdSent = value;
                    SendPropertyChanged("IsKycIdSent");
                    OnIsKycIdSentChanged();
                }
            }
        }

        public event PropertyChangingEventHandler PropertyChanging;

        public event PropertyChangedEventHandler PropertyChanged;

        protected virtual void SendPropertyChanging()
        {
            PropertyChanging?.Invoke(this, emptyChangingEventArgs);
        }

        protected virtual void SendPropertyChanged(string propertyName)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }

        private void Attach_Resultats(Resultat entity)
        {
            SendPropertyChanging();
            entity.Company = this;
        }

        private void Detach_Resultats(Resultat entity)
        {
            SendPropertyChanging();
            entity.Company = null;
        }
    }
 

和相关的表创建脚本:

 create table T_Companies
(
    CompanyId            int identity (10) identity
        primary key nonclustered,
    CompanyName          varchar(1024) not null,
    CompanyTypeId        int           not null
        constraint FK_Company_CompanyType
            references T_CompanyTypes,
    CountryId            int           not null
        constraint FK_Company_Country
            references T_Countries,
    Active               bit           not null,
    AccountId            int,
    CallbackSalt         varchar(1024),
    UserSpaceId          int,
    Login                varchar(1024),
    Pwd                  varchar(1024),
    StatusDate           datetime(23, 3),
    BankStatusCode       int           not null,
    PivotalAccount       varchar(255),
    IsTechnicalAccount   bit           not null,
    CompanyStreetAddress varchar(256),
    CompanyCity          varchar(256),
    CompanyZipCode       varchar(10),
    CompanyVatNumber     varchar(30),
    ContactFirstName     varchar(20),
    ContactLastName      varchar(20),
    IsKycIdSent          bit           not null
)
go
 

对于同一模型,此方法(在项目文件中为nuget引用)有效

 <PackageReference Include="Microsoft.EntityFrameworkCore" Version="2.1.8" />
<PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="2.1.8" />
 

而那些,没有:

 <PackageReference Include="Microsoft.EntityFrameworkCore" Version="2.2.0" />
<PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="2.2.0" />
 

 <PackageReference Include="Microsoft.EntityFrameworkCore" Version="2.2.0" />
<PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="2.1.8" />
 

解决方案

错误消息表明EF Core试图读取必需属性的string值,即应从不在数据库中具有null值,但是底层的数据读取器在某些记录中报告该属性的null值.

查看您的实体模型和相应的数据库表,您可以看到许多string属性-> varchar列之间明显的差异. CompanyStreetAddressCompanyCityCompanyZipCodeCompanyVatNumberContactFirstNameContactLastName-在模型中所有这些都标记为[Required],表中位没有相应的not null约束.

因此,问题是由这些列中的一个或多个引起的.

您需要修复该差异-可能是通过删除[Required]属性,因为该约束已在现有数据中被破坏.

它在某些较旧的EF Core版本中起作用"的事实无关紧要-这是不正确的映射,因此应予以修复.从技术上讲,它不应该从一开始就起作用.但是请记住,EF Core仍在积极开发中,并且存在许多错误,这些错误已在下一版本中修复.很有可能在正常"和无效" EF Core版本之间进行了一些代码更改,该版本修复了以前的不正确行为.

I am using Entity Framework Core in an ASP.NET Core application and Controller action and I haven't changed something to the working code nor to the database but I can't tell what is the query performed by Entity Framework Core.

The controller action:

[HttpGet]
// GET: Administration/Companies
public async Task<ActionResult> Index()
{
    var users = await UserManager.Users.ToListAsync();

    var companyEditVMs = await DB.Companies
    .OrderBy(company => company.CompanyId == 1 
        ? "_" + company.CompanyName 
        : company.CompanyName
    )
    Select(a => new CompanyEditVM(HttpContext, a, users.Where(b => b.CompanyId == a.CompanyId)))
    .ToListAsync();

    return View(companyEditVMs);
}

The trace

SqlNullValueException: Data is Null. This method or property cannot be called on Null values.
System.Data.SqlClient.SqlBuffer.get_String()
System.Data.SqlClient.SqlDataReader.GetString(int i)
lambda_method(Closure , DbDataReader )
Microsoft.EntityFrameworkCore.Storage.Internal.TypedRelationalValueBufferFactory.Create(DbDataReader dataReader)
Microsoft.EntityFrameworkCore.Query.Internal.AsyncQueryingEnumerable<T>+AsyncEnumerator.BufferlessMoveNext(DbContext _, bool buffer, CancellationToken cancellationToken)
Microsoft.EntityFrameworkCore.SqlServer.Storage.Internal.SqlServerExecutionStrategy.ExecuteAsync<TState, TResult>(TState state, Func<DbContext, TState, CancellationToken, Task<TResult>> operation, Func<DbContext, TState, CancellationToken, Task<ExecutionResult<TResult>>> verifySucceeded, CancellationToken cancellationToken)
Microsoft.EntityFrameworkCore.Query.Internal.AsyncQueryingEnumerable<T>+AsyncEnumerator.MoveNext(CancellationToken cancellationToken)
Microsoft.EntityFrameworkCore.Query.Internal.AsyncLinqOperatorProvider+ExceptionInterceptor<T>+EnumeratorExceptionInterceptor.MoveNext(CancellationToken cancellationToken)
System.Linq.AsyncEnumerable.Aggregate_<TSource, TAccumulate, TResult>(IAsyncEnumerable<TSource> source, TAccumulate seed, Func<TAccumulate, TSource, TAccumulate> accumulator, Func<TAccumulate, TResult> resultSelector, CancellationToken cancellationToken) in Aggregate.cs
KYC.Core.Areas.Commercial.Controllers.CompaniesController.Index() in CompaniesController.cs
-
        [HttpGet]
        // GET: Administration/Companies
        public async Task<ActionResult> Index()
        {
            var users = await UserManager.Users.ToListAsync();

            var companyEditVMs = await DB.Companies
                .OrderBy(company => company.CompanyId == 1 
                    ? "_" + company.CompanyName 
                    : company.CompanyName
                )
                .Select(a => new CompanyEditVM(HttpContext, a, users.Where(b => b.CompanyId == a.CompanyId)))
                .ToListAsync();
lambda_method(Closure , object )
Microsoft.Extensions.Internal.ObjectMethodExecutorAwaitable+Awaiter.GetResult()
Microsoft.AspNetCore.Mvc.Internal.ActionMethodExecutor+TaskOfActionResultExecutor.Execute(IActionResultTypeMapper mapper, ObjectMethodExecutor executor, object controller, object[] arguments)
System.Threading.Tasks.ValueTask<TResult>.get_Result()

I even tried to do just var companies = await DB.Companies.ToListAsync(). and I have exactly the same exception.

Maybe I would like to be able to fetch the query performed by EF Core to do that manually so that I can try to figure out what's wrong with the query.

I am wondering what possibly could have happened. Especially since other entities like user or countries can still be fetched from the database.

Any idea how can I troubleshoot the actual underlying issue?

[EDIT]

The only that actually changed in the "code" are the nuget references, I basically upgraded pretty much everything although it didn't break a reference in the code it seems it change how EF Core is somehow (wild guess) interpreting the database.

I did reset my git repository to the point just before the nuget packages update happened and things work.,. I then decided to just update EntityFrameworkCore from 2.0.2 to 2.2.4 (also tried with 2.2.0 and ended up with the same result) and the issue happens again... Not sure what have changed between 2.0.2 and 2.2.0 to trigger this exception (but the model is the same just the EF Core version changed)...

Here is the entity definition, it seems to have been auto-generated with a tool from the database table / schema:


    [Table("T_Companies")]
    public partial class Company : INotifyPropertyChanging, INotifyPropertyChanged
    {
        public override string ToString()
        {
            return CompanyId + " " + CompanyName;
        }

        private static PropertyChangingEventArgs emptyChangingEventArgs = new PropertyChangingEventArgs(string.Empty);

        private int _CompanyId;

        private string _CompanyName;

        private int _CompanyTypeId;

        private int _CountryId;

        private string _CompanyVatNumber;

        private string _CompanyStreetAddress;

        private string _CompanyZipCode;

        private string _CompanyCity;

        private string _ContactLastName;

        private string _ContactFirstName;

        private bool? _Active;

        private int? _AccountId;

        private string _CallbackSalt;

        private int? _UserSpaceId;

        private string _Login;

        private string _Pwd;

        private bool _IsTechnicalAccount;

        private DateTime? _StatusDate;

        private int _BankStatusCode;

        private string _PivotalAccount;

        private CompanyType _CompanyType;

        private Country _Country;

        private bool _IsKycIdSent;

        #region Extensibility Method Definitions
        partial void OnLoaded();
        partial void OnCreated();
        partial void OnCompanyIdChanging(int value);
        partial void OnCompanyIdChanged();
        partial void OnCompanyNameChanging(string value);
        partial void OnCompanyNameChanged();

        partial void OnCompanyCityChanging(string value);
        partial void OnCompanyCityChanged();
        partial void OnCompanyZipCodeChanging(string value);
        partial void OnCompanyZipCodeChanged();
        partial void OnContactLastNameChanging(string value);
        partial void OnContactLastNameChanged();
        partial void OnActiveChanging(bool? value);
        partial void OnActiveChanged();
        partial void OnCompanyTypeIdChanging(int value);
        partial void OnCompanyTypeIdChanged();
        partial void OnCountryIdChanging(int value);
        partial void OnCountryIdChanged();
        partial void OnContactFirstNameChanging(string value);
        partial void OnContactFirstNameChanged();
        partial void OnCompanyVatNumberChanging(string value);
        partial void OnCompanyVatNumberChanged();
        partial void OnCompanyStreetAddressChanged();
        partial void OnCompanyStreetAddressChanging(string value);
        partial void OnAccountIdChanging(int? value);
        partial void OnAccountIdChanged();
        partial void OnCallbackSaltChanging(string value);
        partial void OnCallbackSaltChanged();
        partial void OnUserSpaceIdChanging(int? value);
        partial void OnUserSpaceIdChanged();
        partial void OnLoginChanging(string value);
        partial void OnLoginChanged();
        partial void OnPwdChanging(string value);
        partial void OnPwdChanged();
        partial void OnIsTechnicalAccountChanging(bool value);
        partial void OnIsTechnicalAccountChanged();
        partial void OnStatusDateChanging(DateTime? value);
        partial void OnStatusDateChanged();
        partial void OnBankStatusCodeChanging(int value);
        partial void OnBankStatusCodeChanged();
        partial void OnPivotalAccountChanging(string value);
        partial void OnPivotalAccountChanged();
        partial void OnIsKycIdSentChanging(bool value);
        partial void OnIsKycIdSentChanged();

        #endregion

        public Company()
        {
            OnCreated();
        }

        [Key, Column("CompanyId"), DatabaseGenerated(DatabaseGeneratedOption.Identity)]
        public int CompanyId
        {
            get => _CompanyId;
            set
            {
                if (_CompanyId != value)
                {
                    OnCompanyIdChanging(value);
                    SendPropertyChanging();
                    _CompanyId = value;
                    SendPropertyChanged("CompanyId");
                    OnCompanyIdChanged();
                }
            }
        }

        [DataType(DataType.Text), StringLength(1024), Column("CompanyName"), Required]
        public string CompanyName
        {
            get => _CompanyName;
            set
            {
                if (_CompanyName != value)
                {
                    OnCompanyNameChanging(value);
                    SendPropertyChanging();
                    _CompanyName = value;
                    SendPropertyChanged("CompanyName");
                    OnCompanyNameChanged();
                }
            }
        }

        [Column("CompanyTypeId"), Required]
        public int CompanyTypeId
        {
            get => _CompanyTypeId;
            set
            {
                if (_CompanyTypeId != value)
                {
                    OnCompanyTypeIdChanging(value);
                    SendPropertyChanging();
                    _CompanyTypeId = value;
                    SendPropertyChanged("CompanyTypeId");
                    OnCompanyTypeIdChanged();
                }
            }
        }


        [Column("CountryId"), Required]
        public int CountryId
        {
            get => _CountryId;
            set
            {
                if (CountryId != value)
                {
                    OnCountryIdChanging(value);
                    SendPropertyChanging();
                    _CountryId = value;
                    SendPropertyChanged("CountryId");
                    OnCountryIdChanged();
                }
            }
        }


        [DataType(DataType.Text), StringLength(100), Column("CompanyCity"), Required]
        public string CompanyCity
        {
            get => _CompanyCity;
            set
            {
                if (_CompanyCity != value)
                {
                    OnCompanyCityChanging(value);
                    SendPropertyChanging();
                    _CompanyCity = value;
                    SendPropertyChanged("CompanyCity");
                    OnCompanyCityChanged();
                }
            }
        }

        [DataType(DataType.Text), StringLength(100), Column("CompanyStreetAddress"), Required]
        public string CompanyStreetAddress
        {
            get => _CompanyStreetAddress;
            set
            {
                if (_CompanyStreetAddress != value)
                {
                    OnCompanyStreetAddressChanging(value);
                    SendPropertyChanging();
                    _CompanyStreetAddress = value;
                    SendPropertyChanged("CompanyStreetAddress");
                    OnCompanyStreetAddressChanged();
                }
            }
        }

        [DataType(DataType.Text), StringLength(30), Column("CompanyVatNumber"), Required]
        public string CompanyVatNumber
        {
            get => _CompanyVatNumber;
            set
            {
                if (_CompanyVatNumber != value)
                {
                    OnCompanyVatNumberChanging(value);
                    SendPropertyChanging();
                    _CompanyVatNumber = value;
                    SendPropertyChanged("CompanyVatNumber");
                    OnCompanyVatNumberChanged();
                }
            }
        }


        [DataType(DataType.Text), StringLength(10), Column("CompanyZipCode"), Required]
        public string CompanyZipCode
        {
            get => _CompanyZipCode;
            set
            {
                if (_CompanyZipCode != value)
                {
                    OnCompanyZipCodeChanging(value);
                    SendPropertyChanging();
                    _CompanyZipCode = value;
                    SendPropertyChanged("CompanyZipCode");
                    OnCompanyZipCodeChanged();
                }
            }
        }


        [DataType(DataType.Text), StringLength(1024), Column("ContactLastName"), Required]
        public string ContactLastName
        {
            get => _ContactLastName;
            set
            {
                if (_ContactLastName != value)
                {
                    OnContactLastNameChanging(value);
                    SendPropertyChanging();
                    _ContactLastName = value;
                    SendPropertyChanged("ContactLastName");
                    OnContactLastNameChanged();
                }
            }
        }

        [DataType(DataType.Text), StringLength(1024), Column("ContactFirstName"), Required]
        public string ContactFirstName
        {
            get => _ContactFirstName;
            set
            {
                if (_ContactFirstName != value)
                {
                    OnContactFirstNameChanging(value);
                    SendPropertyChanging();
                    _ContactFirstName = value;
                    SendPropertyChanged("ContactFirstName");
                    OnContactFirstNameChanged();
                }
            }
        }

        [Column("Active"), Required]
        public bool? Active
        {
            get => _Active;
            set
            {
                if (_Active != value)
                {
                    OnActiveChanging(value);
                    SendPropertyChanging();
                    _Active = value;
                    SendPropertyChanged("Active");
                    OnActiveChanged();
                }
            }
        }

        [Column("AccountId")]
        public int? AccountId
        {
            get => _AccountId;
            set
            {
                if (_AccountId != value)
                {
                    OnAccountIdChanging(value);
                    SendPropertyChanging();
                    _AccountId = value;
                    SendPropertyChanged("AccountId");
                    OnAccountIdChanged();
                }
            }
        }

        [DataType(DataType.Text), StringLength(1024), Column("CallbackSalt")]
        public string CallbackSalt
        {
            get => _CallbackSalt;
            set
            {
                if (_CallbackSalt != value)
                {
                    OnCallbackSaltChanging(value);
                    SendPropertyChanging();
                    _CallbackSalt = value;
                    SendPropertyChanged("CallbackSalt");
                    OnCallbackSaltChanged();
                }
            }
        }

        [Column("UserSpaceId")]
        public int? UserSpaceId
        {
            get => _UserSpaceId;
            set
            {
                if (_UserSpaceId != value)
                {
                    OnUserSpaceIdChanging(value);
                    SendPropertyChanging();
                    _UserSpaceId = value;
                    SendPropertyChanged("UserSpaceId");
                    OnUserSpaceIdChanged();
                }
            }
        }

        [DataType(DataType.Text), StringLength(1024), Column("Login")]
        public string Login
        {
            get => _Login;
            set
            {
                if (_Login != value)
                {
                    OnLoginChanging(value);
                    SendPropertyChanging();
                    _Login = value;
                    SendPropertyChanged("Login");
                    OnLoginChanged();
                }
            }
        }

        [DataType(DataType.Text), StringLength(1024), Column("Pwd")]
        public string Pwd
        {
            get => _Pwd;
            set
            {
                if (_Pwd != value)
                {
                    OnPwdChanging(value);
                    SendPropertyChanging();
                    _Pwd = value;
                    SendPropertyChanged("Pwd");
                    OnPwdChanged();
                }
            }
        }

        [Column("IsTechnicalAccount"), Required]
        public bool IsTechnicalAccount
        {
            get => _IsTechnicalAccount;
            set
            {
                if (_IsTechnicalAccount != value)
                {
                    OnIsTechnicalAccountChanging(value);
                    SendPropertyChanging();
                    _IsTechnicalAccount = value;
                    SendPropertyChanged("IsTechnicalAccount");
                    OnIsTechnicalAccountChanged();
                }
            }
        }

        [DataType(DataType.DateTime), Column("StatusDate")]
        public DateTime? StatusDate
        {
            get => _StatusDate;
            set
            {
                if (_StatusDate != value)
                {
                    OnStatusDateChanging(value);
                    SendPropertyChanging();
                    _StatusDate = value;
                    SendPropertyChanged("StatusDate");
                    OnStatusDateChanged();
                }
            }
        }

        [Column("BankStatusCode")]
        public int BankStatusCode
        {
            get => _BankStatusCode;
            set
            {
                if (_BankStatusCode != value)
                {
                    OnBankStatusCodeChanging(value);
                    SendPropertyChanging();
                    _BankStatusCode = value;
                    SendPropertyChanged("BankStatusCode");
                    OnBankStatusCodeChanged();
                }
            }
        }

        [DataType(DataType.Text), StringLength(255), Column("PivotalAccount")]
        public string PivotalAccount
        {
            get => _PivotalAccount;
            set
            {
                if (_PivotalAccount != value)
                {
                    OnPivotalAccountChanging(value);
                    SendPropertyChanging();
                    _PivotalAccount = value;
                    SendPropertyChanged("PivotalAccount");
                    OnPivotalAccountChanged();
                }
            }
        }

        public List<Resultat> Resultats { get; set; }

        public CompanyType CompanyType
        {
            get => _CompanyType;
            set
            {
                var previousValue = _CompanyType;
                if (previousValue != value)
                {
                    SendPropertyChanging();
                    _CompanyType = value;
                    if (value != null)
                    {
                        CompanyTypeId = value.CompanyTypeId;
                    }
                    else
                    {
                        _CompanyTypeId = default;
                    }
                    SendPropertyChanged("CompanyType");
                }
            }
        }

        public Country Country
        {
            get => _Country;
            set
            {
                var previousValue = _Country;
                if (previousValue != value)
                {
                    SendPropertyChanging();
                    _Country = value;
                    _CountryId = value?.CountryId ?? default;
                    SendPropertyChanged("Country");
                }
            }
        }

        [Column("IsKycIdSent"), Required]
        public bool IsKycIdSent
        {
            get => _IsKycIdSent;
            set
            {
                if (_IsKycIdSent != value)
                {
                    OnIsKycIdSentChanging(value);
                    SendPropertyChanging();
                    _IsKycIdSent = value;
                    SendPropertyChanged("IsKycIdSent");
                    OnIsKycIdSentChanged();
                }
            }
        }

        public event PropertyChangingEventHandler PropertyChanging;

        public event PropertyChangedEventHandler PropertyChanged;

        protected virtual void SendPropertyChanging()
        {
            PropertyChanging?.Invoke(this, emptyChangingEventArgs);
        }

        protected virtual void SendPropertyChanged(string propertyName)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }

        private void Attach_Resultats(Resultat entity)
        {
            SendPropertyChanging();
            entity.Company = this;
        }

        private void Detach_Resultats(Resultat entity)
        {
            SendPropertyChanging();
            entity.Company = null;
        }
    }

and the related table creation script:

create table T_Companies
(
    CompanyId            int identity (10) identity
        primary key nonclustered,
    CompanyName          varchar(1024) not null,
    CompanyTypeId        int           not null
        constraint FK_Company_CompanyType
            references T_CompanyTypes,
    CountryId            int           not null
        constraint FK_Company_Country
            references T_Countries,
    Active               bit           not null,
    AccountId            int,
    CallbackSalt         varchar(1024),
    UserSpaceId          int,
    Login                varchar(1024),
    Pwd                  varchar(1024),
    StatusDate           datetime(23, 3),
    BankStatusCode       int           not null,
    PivotalAccount       varchar(255),
    IsTechnicalAccount   bit           not null,
    CompanyStreetAddress varchar(256),
    CompanyCity          varchar(256),
    CompanyZipCode       varchar(10),
    CompanyVatNumber     varchar(30),
    ContactFirstName     varchar(20),
    ContactLastName      varchar(20),
    IsKycIdSent          bit           not null
)
go

[EDIT 2]

For the very same model, this (in the project file the nuget references) works

<PackageReference Include="Microsoft.EntityFrameworkCore" Version="2.1.8" />
<PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="2.1.8" />

while those ones, no:

<PackageReference Include="Microsoft.EntityFrameworkCore" Version="2.2.0" />
<PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="2.2.0" />

<PackageReference Include="Microsoft.EntityFrameworkCore" Version="2.2.0" />
<PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="2.1.8" />

解决方案

The error message indicates that EF Core is trying to read string value for a required property, i.e. a property which should never has null value in the database, but instead the underlying data reader reports null value for that property in some record{s).

Looking at your entity model and corresponding database table, you can see the obvious discrepancy for many string properties -> varchar columns. CompanyStreetAddress, CompanyCity, CompanyZipCode, CompanyVatNumber, ContactFirstName, ContactLastName - all these are marked as [Required] in the model, bit have no corresponding not null constraint in the table.

So the problem is caused by one or more of these columns.

You need to fix that discrepancy - probably by removing [Required] attribute because the constraint is already broken in the existing data.

The fact that it "works" in some older EF Core version doesn't matter - that's incorrect mapping and as such should be fixed. Technically it shouldn't worked from the beginning. But remember that EF Core is still in active development and has many bugs which are fixed in the next release(s). Most likely some code change was made between "working" and "non working" EF Core version which fixes the previous incorrect behavior.

这篇关于实体框架核心:"SqlNullValueException:数据为空."如何解决问题?的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!

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