存储过程为列返回值，但 FromSqlRaw 为类属性返回 null

Posted 2023-03-30

【中文标题】存储过程为列返回值，但 FromSqlRaw 为类属性返回 null

【英文标题】：Stored Procedure returns value for a column but FromSqlRaw returns null for the class property

【发布时间】：2021-12-23 07:25:14

【问题描述】：

我有一个由多种方法调用的类。这个类是：

public class Policy : EntityObject

    public Guid PolicyId  get; set; 
    public Guid CustomerId  get; set; 
    public string PolicyNumber  get; set; 
    [NotMapped]
    public string TrimmedPolicyNumber  get; set; 
    public DateTime? PolicyEffectiveDate  get; set; 
    public DateTime? PolicyExpirationDate  get; set; 
    [NotMapped]
    public string PolicyType  get; set; 
    public string InsuranceCompany  get; set; 
    public string WritingCompany  get; set; 
    [NotMapped]
    public string BillMethod_PaymentPlan  get; set; 
    [NotMapped]
    public decimal? FullTermPremium  get; set; 
    [NotMapped]
    public string AccountExecutive  get; set; 
    [NotMapped]
    public string AccountRepresentative  get; set; 

    [NotMapped]
    public string PolicyLineOfBusiness  get; set; 

    [NotMapped]
    public string Status  get; set; 

现在我有以下存储过程：

Create PROCEDURE [GetActivePoliciesByCustomer]
@CustomerId UNIQUEIDENTIFIER
AS
    SET NOCOUNT ON;
    Select
        c.CustId as CustomerId
        , p.PolId as PolicyId
        , p.PolNo as PolicyNumber
        , p.PolTypeLOB as [PolicyLineOfBusiness]
        , p.PolEffDate as PolicyEffectiveDate
        , p.PolExpDate as PolicyExpirationDate
        , cmp.Name as InsuranceCompany
        , wcmp.Name as WritingCompany
        , pr.Description as [Status]
    FROM
        Policies p
        (Further details have been omitted as it is not important)
GO

此存储过程返回上面列出的所有字段的数据。但是，当我拨打以下电话时：

public async Task<List<Policy>> GetActivePoliciesByCustomerId(Guide customerId)

    var activePolicies = await _context.Policy
        .FromSqlRaw<Policy>("EXEC [GetActivePoliciesByCustomer] @customerId=0", customerId)
        .ToListAsync();

    return activepolicies;

在调试会话期间，我看到 Status 和 PolicyLineOfBusiness 设置为 null。我怀疑[NotMapped] 属性会阻止这些字段被映射，我已经验证了这一点。如果我删除 [NotMapped] 属性，我会看到填充了 Status 和 PolicyLineOfBusiness 字段。但是，这个类（Policy）被另一个调用使用：

public async Task<Policy> GetPolicyByPolicyId(Guid id)

    var policyDetails = await _context.Policy
        .FromSqlRaw<Policy>("EXEC [GetPolicyDetailsByPolicyId] @policyId=0", id)
        .ToListAsync();

    return policyDetails.FirstOrDefault();

它正在调用的存储过程：

CREATE PROCEDURE [GetPolicyDetailsByPolicyId]
@PolicyId UNIQUEIDENTIFIER
AS
    SET NOCOUNT ON;

    SELECT TOP 1
        p.PolId as PolicyId
        , p.CustId as CustomerId
        , p.PolNo as PolicyNumber
        , p.ShortPolNo as TrimmedPolicyNumber
        , p.PolEffDate as PolicyEffectiveDate
        , p.PolExpDate as PolicyExpirationDate
        , p.PolTypeLOB as PolicyType
        , c.[Name] as InsuranceCompany
        , wc.[Name] as WritingCompany
        , p.BillMethod_PaymentPlan
        , p.FullTermPremium
        , e1.[LastName] as AccountExecutive
        , CONCAT(e.FirstName, ' ', e.LastName) as AccountRepresentative 
    From
        Policies p
        (Further details have been omitted as it is not important)

如果我从上述属性（PolicyLineOfBusiness 和 Status）中删除 [NotMapped] 属性并使用以前的方法（GetPolicyByPolicyId）调用上述存储过程，我会得到一个异常：

System.InvalidOperationException: The required column 'PolicyLineOfBusiness' was not present in the results of a 'FromSql' operation.

那么我该如何解决使属性可选的问题，同时它们应该能够映射到两个不同的存储过程返回的字段？如果有更好的方法，我愿意接受建议。提前致谢。

【问题讨论】：

这是关于这里回答的内容：Assigning NotMapped property value after "regular" (mapped) property value has been assigned 吗？

也许您可以拥有一个具有公共字段的类，并为第二个存储过程创建另一个具有继承性的类？或者它不是一种选择？

不相关，但为什么名为 'GetPolicyDetailsByPolicyId' 的 proc 需要 TOP 1 ？

您使用的是哪个 dbms？ （上面的 SQL 是特定于产品的。）

请将sample code 设为最小且完整。大多数Policy 属性和数据库列都可以删除，并添加了_context 的声明。

【参考方案1】：

这个解决方案可以帮助你。

首先，我们需要使用继承。

其次，我们必须创建一个鉴别器来处理 SP 和类。

最后，我们在存储过程中设置判别器。

让我们看一些代码。

使用您的课程：

public class Policy : EntityObject

    public Guid PolicyId  get; set; 
    public Guid CustomerId  get; set; 
    public string PolicyNumber  get; set;     
    public DateTime? PolicyEffectiveDate  get; set; 
    public DateTime? PolicyExpirationDate  get; set; 
    public string InsuranceCompany  get; set; 
    public string WritingCompany  get; set; 


public class CustomerPolicy : Policy

    public string Status  get; set; 
    public string PolicyLineOfBusiness  get; set;         


public class DetailedPolicy : Policy
    
    public string TrimmedPolicyNumber  get; set; 
    public string PolicyType  get; set; 
    public string BillMethod_PaymentPlan  get; set;     
    public decimal? FullTermPremium  get; set;     
    public string AccountExecutive  get; set; 
    public string AccountRepresentative  get; set; 

设置鉴别器：

public class Policy : EntityObject

    public Guid PolicyId  get; set; 
    // ...
    [NotMapped]  
    public string discriminator  get; set;  

然后，流畅的 API 设置

// ...
public DbSet<Policy> Policy  get; set; 

protected override void OnModelCreating(ModelBuilder modelBuilder)

  // here you can use enum, byte, int, etc. instead of string.
  modelBuilder.Entity<Policy>()
    .HasDiscriminator<string>("discriminator")
    .HasValue<Policy>(nameof(Policy)) 
    .HasValue<CustomerPolicy>(nameof(CustomerPolicy))
    .HasValue<DetailedPolicy>(nameof(DetailedPolicy));
  // ...

在这一步中，我们必须将鉴别器（类名）传递给存储过程。

CREATE PROCEDURE [GetPolicyDetailsByPolicyId]
@PolicyId UNIQUEIDENTIFIER
AS
    SET NOCOUNT ON;

    SELECT TOP 1
        p.PolId as PolicyId
        , p.CustId as CustomerId
        , p.PolNo as PolicyNumber
        , p.ShortPolNo as TrimmedPolicyNumber
        , p.PolEffDate as PolicyEffectiveDate
        , p.PolExpDate as PolicyExpirationDate
        , p.PolTypeLOB as PolicyType
        , c.[Name] as InsuranceCompany
        , wc.[Name] as WritingCompany
        , p.BillMethod_PaymentPlan
        , p.FullTermPremium
        , e1.[LastName] as AccountExecutive
        , CONCAT(e.FirstName, ' ', e.LastName) as AccountRepresentative 

        // Add the discriminator here
        ,'DetailedPolicy' discriminator

    From
        Policies p
        (Further details have been omitted as it is not important)

在另一个 sp 中重复。

Create PROCEDURE [GetActivePoliciesByCustomer]
@CustomerId UNIQUEIDENTIFIER
AS
    SET NOCOUNT ON;
    Select
        c.CustId as CustomerId
        , p.PolId as PolicyId
        , p.PolNo as PolicyNumber
        , p.PolTypeLOB as [PolicyLineOfBusiness]
        , p.PolEffDate as PolicyEffectiveDate
        , p.PolExpDate as PolicyExpirationDate
        , cmp.Name as InsuranceCompany
        , wcmp.Name as WritingCompany
        , pr.Description as [Status]

        // Add the discriminator here
        'CustomerPolicy' discriminator
         
    FROM
        Policies p
        (Further details have been omitted as it is not important)
GO

EF 上下文调用：

using Microsoft.EntityFrameworkCore;
using Microsoft.Data.SqlClient;

// ...

var activePolicies = await context.Policy
    .FromSqlRaw("exec [GetActivePoliciesByCustomer] @customerId", 
        new SqlParameter("customerId", customerId))
    .AsAsyncEnumerable();

var policyDetails = await context.Policy
    .FromSqlRaw("exec [GetPolicyDetailsByPolicyId] @policyId", 
        new SqlParameter("policyId", id))
    .AsAsyncEnumerable();

注意：您可能需要使用 AsAsyncEnumerable 或 IQueryable 来正确转换您的类。

更新：

注意2：如果编译器出现问题，你必须用其他派生类的null填充所有字段。

例如：

CREATE PROCEDURE [GetPolicyDetailsByPolicyId]
// ...
        ,'DetailedPolicy' discriminator
        ,null Status
        ,null PolicyLineOfBusiness 
// ...

以下是 .NET Core 5 和 EF Core 5 的示例：

public class Policy

  public int field1  get; set;     
  [NotMapped]
  public string discriminator  get; set;  


public class Policy2 : Policy

  public int? field2  get; set; 


public class Policy3 : Policy

  public int? field3  get; set; 

流畅的 API：

// ...
public DbSet<Policy> Policies  get; set; 

protected override void OnModelCreating(ModelBuilder modelBuilder)

  modelBuilder.Entity<Policy>().HasNoKey();
  
  modelBuilder.Entity<Policy>()
    .HasDiscriminator<string>("discriminator")
    .HasValue<Policy>(nameof(Policy))
    .HasValue<Policy2>(nameof(Policy2))
    .HasValue<Policy3>(nameof(Policy3));

  //...

自定义存储过程：

create procedure GenPolicyQuery
    @id int,
    @source varchar(10)
as

declare @field1 int, @field2 int, @field3 int

if @source =  'Policy'
    set @field1 = @id
else if @source = 'Policy2'
    select @field1 = 10, @field2 = @id
else if @source = 'Policy3'
    select @field1 = 10, @field3 = @id

select @field1 field1, @field2 field2, @field3 field3, @source discriminator

go

结果：

using System.Linq;
using Microsoft.EntityFrameworkCore;
using Microsoft.Data.SqlClient;
using Newtonsoft.Json;
// ...

var policy1 = db.Policies
  .FromSqlRaw("exec GenPolicyQuery @id, @source", 
    new SqlParameter("id", 10), 
    new SqlParameter("source", "Policy"))        
  .AsEnumerable();

var policy2 = db.Policies
  .FromSqlRaw("exec GenPolicyQuery @id, @source", 
    new SqlParameter("id", 20), 
    new SqlParameter("source", "Policy2"))
  .AsEnumerable();

var policy3 = db.Policies
  .FromSqlRaw("exec GenPolicyQuery @id, @source", 
    new SqlParameter("id", 30), 
    new SqlParameter("source", "Policy3"))
  .AsEnumerable();
    
Console.WriteLine(JsonConvert.SerializeObject(policy1));
Console.WriteLine(JsonConvert.SerializeObject(policy2));
Console.WriteLine(JsonConvert.SerializeObject(policy3))

// Result
/*
  ["field1":10,"discriminator":"Policy"]
  ["field2":20,"field1":10,"discriminator":"Policy2"]
  ["field3":30,"field1":10,"discriminator":"Policy3"]
*/

【参考方案2】：

您的Policies 类同时具有PolicyType 和PolicyLineOfBusiness 属性。

在GetActivePoliciesByCustomer 过程中，列p.PolTypeLOB 别名为PolicyLineOfBusiness，但在GetPolicyDetailsByPolicyId 过程中，列p.PolTypeLOB 别名为PolicyType

所以，两个属性的 origin 列是相同的，我不明白原因， 但为避免第二个过程出现异常，您可以对其进行修改，同时添加PolicyLineOfBusiness 所需的输出：

CREATE PROCEDURE [GetPolicyDetailsByPolicyId]
@PolicyId UNIQUEIDENTIFIER
AS
    SET NOCOUNT ON;

    SELECT TOP 1
        p.PolId as PolicyId
        , p.CustId as CustomerId
        , p.PolNo as PolicyNumber
        , p.ShortPolNo as TrimmedPolicyNumber
        , p.PolEffDate as PolicyEffectiveDate
        , p.PolExpDate as PolicyExpirationDate
        , p.PolTypeLOB as PolicyType
        , p.PolTypeLOB as PolicyLineOfBusiness /* *** ADD THIS LINE  *** */
        , c.[Name] as InsuranceCompany
        , wc.[Name] as WritingCompany
        , p.BillMethod_PaymentPlan
        , p.FullTermPremium
        , e1.[LastName] as AccountExecutive
        , CONCAT(e.FirstName, ' ', e.LastName) as AccountRepresentative 
    From
        Policies p
        (Further details have been omitted as it is not important)

【参考方案3】：

由于 PolicyLineOfBusiness 属性存在于您的域模型中。因此，如果您删除属性（未映射），两个 SP 都必须返回该属性值。但是通过删除该属性，您的第二个 SP 将给出异常，第一个 SP 将获取数据。所以这意味着第二个 SP 不想返回 PolicyLineOfBusiness 属性。

不幸的是，您无法通过删除域模型属性中的属性 (NotMapped) 来强制编写 PolicyLineOfBusiness 属性。因此，如果要保持域模型相同，则必须从第二个 SP 返回属性。

CREATE PROCEDURE [GetPolicyDetailsByPolicyId]
@PolicyId UNIQUEIDENTIFIER
AS
    SET NOCOUNT ON;

    SELECT TOP 1
        p.PolId as PolicyId
        , p.CustId as CustomerId
        , p.PolNo as PolicyNumber
        , p.ShortPolNo as TrimmedPolicyNumber
        , p.PolEffDate as PolicyEffectiveDate
        , p.PolExpDate as PolicyExpirationDate
        , p.PolTypeLOB as PolicyType
        , c.[Name] as InsuranceCompany
        , wc.[Name] as WritingCompany
        , p.BillMethod_PaymentPlan
        , p.FullTermPremium
        , "" As PolicyLineOfBusiness --Have to add this as the domain model contain this property
        , e1.[LastName] as AccountExecutive
        , CONCAT(e.FirstName, ' ', e.LastName) as AccountRepresentative 
    From
        Policies p
        (Further details have been omitted as it is not important)

如果您不想这样做，请为 2 个 SP 创建 2 个不同的模型。

【参考方案4】：

对于单独的存储过程，您需要有单独的模型，因为两个存储过程中的列不同。