重復鍵值違反唯一約束|EFCorePostgreSQL

我見過類似的問題，但似乎都與我的問題無關。

我有 2 個物體、EducationResult鏈接TestModule和Student附加資訊，
以及TestModule對這些問題的Questions深入了解。Answers

當嘗試再次將相同的 TestModule 與相同的 Student 鏈接時，我收到錯誤：

重復鍵值違反唯一約束“IX_EducationResults_TestModuleId”

我不認為 TestModule 物體是唯一的，問題肯定在于配置。

EducationResult：

public class EducationResult : AuditableEntity
{
    public EducationResultId EducationResultId { get; set; }

    public IsDone IsDone { get; set; }

    public Score Score { get; set; }

    public MaxScore MaxScore { get; set; }

    public IsPassed IsPassed { get; set; }

    // Student
    public StudentId StudentId { get; set; }

    public virtual Student Student { get; set; }

    // TestModule
    public TestModuleId TestModuleId { get; set; }

    public virtual TestModule TestModule { get; set; }
}

TestModule：

public class TestModule : AuditableEntity
{
    public TestModuleId TestModuleId { get; set; }

    public TestModuleName Name { get; set; }

    public TestModuleLevel Level { get; set; }

    public TestModuleDescription Description { get; set; }

    public ICollection<Question> Questions { get; set; }
}

和配置：

public class EducationResultConfiguration : IEntityTypeConfiguration<EducationResult>
{
    public void Configure(EntityTypeBuilder<EducationResult> builder)
    {
        builder.HasKey(x => x.EducationResultId);
     
        builder.Property(x => x.EducationResultId)
            .HasConversion(x => x.Value, x => new EducationResultId(x));
        
        builder.Property(x => x.IsDone)
            .HasConversion(x => x.Value, x => new IsDone(x));

        builder.Property(x => x.Score)
            .HasConversion(x => x.Value, x => new Score(x));
        
        builder.Property(x => x.MaxScore)
            .HasConversion(x => x.Value, x => new MaxScore(x));
        
        builder.Property(x => x.IsPassed)
            .HasConversion(x => x.Value, x => new IsPassed(x));

        // Entity configurations
        builder
            .HasOne(x => x.Student)
            .WithMany(x => x.EducationResults)
            .HasForeignKey(q => q.StudentId);
        
        builder
            .HasOne(x => x.TestModule)
            .WithOne()
            .HasForeignKey<EducationResult>(x => x.TestModuleId);
    }
}

public class TestModuleConfiguration : IEntityTypeConfiguration<TestModule>
{
    public void Configure(EntityTypeBuilder<TestModule> builder)
    {
        builder.HasKey(x => x.TestModuleId);

        builder.Property(x => x.TestModuleId)
            .HasConversion(x => x.Value, x => new TestModuleId(x));

        builder.Property(x => x.Name)
            .HasConversion(x => x.Value, x => new TestModuleName(x));

        builder.Property(x => x.Level)
            .HasConversion(x => x.Value, x => new TestModuleLevel(x));

        builder.Property(x => x.Description)
            .HasConversion(x => x.Value, x => new TestModuleDescription(x));

        builder
            .OwnsMany(module => module.Questions, question =>
            {
                #region Question owner
                
                question.WithOwner(x => x.TestModule).HasForeignKey(x => x.TestModuleId);

                #endregion

                #region Question properties

                question.HasKey(x => x.QuestionId);
                question.Property(x => x.QuestionId)
                    .HasConversion(x => x.Value, x => new QuestionId(x));

                question.Property(x => x.QuestionText)
                    .HasConversion(x => x.Value, x => new QuestionText(x));

                question.Property(x => x.Explanation)
                    .HasConversion(x => x.Value, x => new QuestionExplanation(x));

                question.Property(x => x.TestModuleId)
                    .HasConversion(x => x.Value, x => new TestModuleId(x));

                #endregion

                question.OwnsMany(x => x.Answers, answer =>
                {
                    #region Answer owner

                    answer.WithOwner(x => x.Question).HasForeignKey(x => x.QuestionId);

                    #endregion

                    #region Answer properties

                    answer.HasKey(x => x.QuestionAnswerId);
        
                    answer.Property(x => x.QuestionAnswerId)
                        .HasConversion(x => x.Value, x => new QuestionAnswerId(x));
        
                    answer.Property(x => x.Text)
                        .HasConversion(x => x.Value, x => new QuestionAnswerText(x));

                    answer.Property(x => x.IsCorrect)
                        .HasConversion(x => x.Value, x => new Correct(x));
        
                    answer.Property(x => x.QuestionId)
                        .HasConversion(x => x.Value, x => new QuestionId(x));

                    #endregion
                });
            });
    }
}

和錯誤：

保存背景關系型別“wisse.Persistence.DAL.WisseDbContext”的更改時，資料庫中發生例外。Microsoft.EntityFrameworkCore.DbUpdateException：保存物體更改時出錯。有關詳細資訊，請參閱內部例外。---> Npgsql.PostgresException (0x80004005): 23505: 重復鍵值違反唯一約束“IX_EducationResults_TestModuleId”

我想使用 TestModule 內容，比如代碼中的靜態欄位，
這些值應該是可重用的，即使它們已經在 EducationResult 中使用過 有
什么問題以及如何允許多次使用同一個物體？

uj5u.com熱心網友回復：

您已經為 EducationResult 和 TestModule 宣告了 1:1 的關系：

public void Configure(EntityTypeBuilder<EducationResult> builder)
{
    ...
    builder
        .HasOne(x => x.TestModule) // EducationResult can have one TestResult
        .WithOne() // TestResult can have ONE EducationResult
        .HasForeignKey<EducationResult>(x => x.TestModuleId);
}

在這種情況下，EF Core 將生成一個約束以確保僅在一個 EducationResult 中參考一個 TestModule。

對于 TestModule 可以在 EducationResult 中多次參考，您需要宣告一個關系 1:n ：

public void Configure(EntityTypeBuilder<EducationResult> builder)
{
    ...
    builder
        .HasOne(x => x.TestModule) // EducationResult can have one TestResult
        .WithMany() // TestResult can have MANY EducationResult
        .HasForeignKey<EducationResult>(x => x.TestModuleId);
}

就像你對關系 EducationResult|Student 所做的那樣，一個學生可以有多個結果。

標籤：C＃。网PostgreSQL实体框架核心npgsql

上一篇：PostgreSQL：在A列的id之間計算B列的常見值

下一篇：NODEJS：對連接表中的資料進行分組