重构项目结构，移除Assignment相关功能，优化Submission模块

Entities/Contracts/AppMainStruct.cs

@@ -43,18 +43,11 @@ namespace Entities.Contracts
 		veryHard
 	}
 
-	public enum QuestionType : byte
+	public enum TypeNameType : byte
 	{
-		Unknown = 0,
-		Spelling,           // 拼写
-		Pronunciation,      // 给带点字选择正确读音
-		WordFormation,      // 组词
-		FillInTheBlanks,    // 选词填空 / 补充词语
-		SentenceDictation,  // 默写句子
-		SentenceRewriting,  // 仿句 / 改写句子
-		ReadingComprehension, // 阅读理解
-		Composition         // 作文
-							
+		Subject = 0,
+		QuestionType = 1,
+		ExamType = 2,
 	}
 
 	public enum SubjectAreaEnum : byte
@@ -90,7 +83,7 @@ namespace Entities.Contracts
 		ComputerScience // 计算机科学
 	}
 
-	public enum AssignmentStructType : byte
+	public enum ExamStructType : byte
 	{
 		[Display(Name = "根节点", Description = "根")]
 		Root,
@@ -105,26 +98,12 @@ namespace Entities.Contracts
 		[Display(Name = "选项", Description = "选")]
 		Option
 	}
-
-	public enum ExamType : byte
+	
+	public enum UserRoles
 	{
-		[Display(Name = "期中考试", Description = "中")]
-		MidtermExam,
-
-		[Display(Name = "期末考试", Description = "末")]
-		FinalExam,
-
-		[Display(Name = "月考", Description = "月")]
-		MonthlyExam,
-
-		[Display(Name = "周考", Description = "周")]
-		WeeklyExam,
-
-		[Display(Name = "平时测试", Description = "平")]
-		DailyTest,
-
-		[Display(Name = "AI测试", Description = "AI")]
-		AITest,
+		Student,
+		Teacher,
+		Admin
 	}
 
 	public enum SubmissionStatus

Entities/Contracts/AssignmentClass.cs

@@ -1,36 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.ComponentModel.DataAnnotations.Schema;
-using System.ComponentModel.DataAnnotations;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
-
-namespace Entities.Contracts
-{
-	[Table("assignment_class")]
-	public class AssignmentClass
-	{
-		[Key]
-		[Column("assignment_id", Order = 0)]
-		[ForeignKey("Assignment")]
-		public Guid AssignmentId { get; set; }
-
-		[Key]
-		[Column("class_id", Order = 1)]
-		[ForeignKey("Class")]
-		public Guid ClassId { get; set; }
-
-		[Column("assigned_at")]
-		public DateTime AssignedAt { get; set; }
-
-		[Column("deleted")]
-		public bool IsDeleted { get; set; }
-
-		// Navigation Properties
-		public Assignment Assignment { get; set; }
-		public Class Class { get; set; }
-
-
-	}
-}

Entities/Contracts/AssignmentQuestion.cs

@@ -1,76 +0,0 @@
-using Microsoft.EntityFrameworkCore;
-using System;
-using System.Collections.Generic;
-using System.ComponentModel.DataAnnotations.Schema;
-using System.ComponentModel.DataAnnotations;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
-using Entities.DTO;
-
-namespace Entities.Contracts
-{
-	[Table("assignment_questions")]
-	public class AssignmentQuestion
-	{
-		[Key]
-		[Column("id")]
-		public Guid Id { get; set; }
-
-		[Column("question_id")]
-		public Guid? QuestionId { get; set; }
-
-		[Column("title")]
-		[MaxLength(1024)]
-		public string? Title { get; set; }
-
-		[Column("description")]
-		public Guid? QuestionContextId { get; set; }
-
-		[Required]
-		[Column("question_number")]
-		public byte Index { get; set; }
-
-		[Column("sequence")]
-		public string Sequence { get; set; } = string.Empty;
-
-		[Column("parent_question_group_id")]
-		public Guid? ParentAssignmentQuestionId { get; set; }
-
-		[Column("group_state")]
-		public AssignmentStructType StructType { get; set; } = AssignmentStructType.Question;
-
-		public QuestionType Type { get; set; } = QuestionType.Unknown;
-
-		[Column("created_at")]
-		public DateTime CreatedAt { get; set; }
-
-		[Column("score")]
-		public float? Score { get; set; }
-
-		public bool BCorrect { get; set; }
-
-		[Column("deleted")]
-		public bool IsDeleted { get; set; }
-
-
-		public Question? Question { get; set; }
-		public Assignment? Assignment { get; set; }
-
-		[ForeignKey(nameof(QuestionContextId))]
-		public QuestionContext? QuestionContext { get; set; }
-
-		public ICollection<SubmissionDetail> SubmissionDetails { get; set; }
-
-		[ForeignKey(nameof(ParentAssignmentQuestionId))]
-		public AssignmentQuestion? ParentAssignmentQuestion { get; set; }
-		public ICollection<AssignmentQuestion> ChildrenAssignmentQuestion { get; set; } = new List<AssignmentQuestion>();
-
-
-		public AssignmentQuestion()
-		{
-			Id = Guid.NewGuid();
-			SubmissionDetails = new HashSet<SubmissionDetail>();
-		}
-	}
-}

Entities/Contracts/Class.cs

@@ -10,19 +10,24 @@ namespace Entities.Contracts
 	{
 		[Key]
 		[Column("class_id")]
-		public int ClassId { get; set; }
+		public Guid Id { get; set; }
 
 		[Column("grade_id")]
-		public int GradeId { get; set; }
-		public Grade Grade { get; set; }
+		public Guid GradeId { get; set; }
+		[ForeignKey(nameof(GradeId))]
+		public virtual Grade Grade { get; set; }
+
+		[Column("index")]
+		public byte Index { get; set; }
 
 		[Column("class_name")]
 		[MaxLength(30)]
 		public string ClassName { get; set; }
 
 		[Column("head_teacher_id")]
-		public int? HeadTeacherId { get; set; }
-		public User HeadTeacher { get; set; }
+		public Guid? HeadTeacherId { get; set; }
+		[ForeignKey(nameof(HeadTeacherId))]
+		public virtual User HeadTeacher { get; set; }
 
 		[Column("created_at")]
 		public DateTime CreatedAt { get; set; }
@@ -34,15 +39,20 @@ namespace Entities.Contracts
 		public bool IsDeleted { get; set; }
 
 		// Navigation Properties
-		public ICollection<ClassTeacher> ClassTeachers { get; set; }
-		public ICollection<ClassStudent> ClassStudents { get; set; }
-		public ICollection<AssignmentClass> AssignmentClasses { get; set; }
+
+		[NotMapped]
+		public ICollection<ClassUser> Techers => ClassUsers.Where(cu => cu.User.Role == UserRoles.Teacher).ToList();
+
+		[NotMapped]
+		public ICollection<ClassUser> Students => ClassUsers.Where(cu => cu.User.Role == UserRoles.Student).ToList();
+
+		[InverseProperty(nameof(ClassUser.Class))]
+		public virtual ICollection<ClassUser> ClassUsers { get; set; }
 
 		public Class()
 		{
-			ClassStudents = new HashSet<ClassStudent>();
-			ClassTeachers = new HashSet<ClassTeacher>();
-			AssignmentClasses = new HashSet<AssignmentClass>();
+			Id = Guid.NewGuid();
+			ClassUsers = new HashSet<ClassUser>();
 			CreatedAt = DateTime.Now;
 			UpdatedAt = DateTime.Now;
 		}

Entities/Contracts/ClassStudent.cs

@@ -1,34 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.ComponentModel.DataAnnotations.Schema;
-using System.ComponentModel.DataAnnotations;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
-
-namespace Entities.Contracts
-{
-	[Table("class_student")]
-	public class ClassStudent
-	{
-		[Key]
-		[Column("class_id", Order = 0)]
-		[ForeignKey("Class")]
-		public Guid ClassId { get; set; }
-
-		[Key]
-		[Column("student_id", Order = 1)]
-		[ForeignKey("Student")]
-		public Guid StudentId { get; set; }
-
-		[Column("enrollment_date")]
-		public DateTime EnrollmentDate { get; set; }
-
-		[Column("deleted")]
-		public bool IsDeleted { get; set; }
-
-		// Navigation Properties
-		public Class Class { get; set; }
-		public User Student { get; set; }
-	}
-}

Entities/Contracts/ClassTeacher.cs

@@ -1,29 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.ComponentModel.DataAnnotations;
-using System.ComponentModel.DataAnnotations.Schema;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
-
-namespace Entities.Contracts
-{
-	[Table("class_teachers")]
-	public class ClassTeacher
-	{
-		[Key] 
-		[Column("class_id")]
-		public Guid ClassId { get; set; }
-		[ForeignKey(nameof(ClassId))]
-		public Class Class { get; set; }
-
-		[Key] 
-		[Column("teacher_id")] 
-		public Guid TeacherId { get; set; }
-		[ForeignKey(nameof(TeacherId))]
-		public User Teacher { get; set; }
-
-		[Column("subject_taught")]
-		public SubjectAreaEnum SubjectTaught { get; set; }
-	}
-}

Entities/Contracts/ClassUser.cs

@@ -0,0 +1,56 @@
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations.Schema;
+using System.ComponentModel.DataAnnotations;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using Microsoft.EntityFrameworkCore;
+
+namespace Entities.Contracts
+{
+	/// <summary>
+	/// 班级用户关联实体类
+	/// 表示用户与班级之间的多对多关系
+	/// </summary>
+	[Table("class_user")]
+    [PrimaryKey(nameof(ClassId), nameof(UserId))]
+    public class ClassUser
+    {
+        /// <summary>
+        /// 班级ID，复合主键的一部分，外键
+        /// 关联到Class表中的班级
+        /// </summary>
+        [Key]
+        [Column("class_id", Order = 0)]
+        public Guid ClassId { get; set; }
+        [ForeignKey(nameof(ClassId))]
+		public virtual Class Class { get; set; }
+		/// <summary>
+		/// 用户ID，复合主键的一部分，外键
+		/// 关联到User表中的用户用户
+		/// </summary>
+		[Key]
+        [Column("student_id", Order = 1)]
+        public Guid UserId { get; set; }
+		[ForeignKey(nameof(UserId))]
+		public virtual User User { get; set; }
+
+		/// <summary>
+		/// 入学日期
+		/// 记录用户加入该班级的日期
+		/// </summary>
+		[Column("enrollment_date")]
+        public DateTime EnrollmentDate { get; set; }
+
+        /// <summary>
+        /// 是否已删除
+        /// 软删除标记，true表示已删除
+        /// </summary>
+        [Column("deleted")]
+        public bool IsDeleted { get; set; }
+
+
+
+    }
+}

Entities/Contracts/Exam.cs

@@ -9,8 +9,8 @@ using Entities.DTO;
 
 namespace Entities.Contracts
 {
-	[Table("assignments")]
-	public class Assignment
+	[Table("exams")]
+	public class Exam
 	{
 		[Key]
 		[Column("id")]
@@ -24,12 +24,26 @@ namespace Entities.Contracts
 		[Column("description")]
 		public string Description { get; set; }
 
-		[Column("subject_area")]
-		public SubjectAreaEnum SubjectArea { get; set; }
+		[Column("subject_id")]
+		public Guid SubjectId { get; set; }
+		[ForeignKey(nameof(SubjectId))]
+		public virtual Subject Subject { get; set; }
 
 		[Required]
 		[Column("exam_struct_id")]
+		[ForeignKey(nameof(ExamStruct))]
 		public Guid ExamStructId { get; set; }
+		public virtual ExamQuestion ExamStruct { get; set; }
+
+		[Column("exam_type_id")]
+		public Guid ExamTypeId { get; set; }
+		[ForeignKey(nameof(ExamTypeId))]
+		public virtual ExamType ExamType { get; set; }
+
+		[Column("created_by")]
+		public Guid CreatorId { get; set; }
+		[ForeignKey(nameof(CreatorId))]
+		public virtual User Creator { get; set; }
 
 		[Required]
 		[Column("due_date")]
@@ -41,13 +55,9 @@ namespace Entities.Contracts
 		[Column("score")]
 		public float Score { get; set; }
 
+		[Column("name")]
 		public string Name { get; set; } = string.Empty;
 
-		public ExamType ExamType { get; set; } = ExamType.DailyTest;
-
-		[Column("created_by")]
-		public Guid CreatorId { get; set; }
-
 		[Column("created_at")]
 		public DateTime CreatedAt { get; set; }
 
@@ -57,61 +67,53 @@ namespace Entities.Contracts
 		[Column("deleted")]
 		public bool IsDeleted { get; set; } = false;
 
-		// Navigation Properties
 
-		[ForeignKey(nameof(CreatorId))]
-		public User Creator { get; set; }
-		public ICollection<AssignmentClass> AssignmentClasses { get; set; }
+		[InverseProperty(nameof(ExamAttachment.Exam))]
+		public virtual ICollection<ExamAttachment> ExamAttachments { get; set; }
+		[InverseProperty(nameof(Submission.Exam))]
+		public virtual ICollection<Submission> Submissions { get; set; }
 
-		[ForeignKey(nameof(ExamStructId))]
-		public AssignmentQuestion ExamStruct { get; set; }
-		public ICollection<AssignmentAttachment> AssignmentAttachments { get; set; }
-		public ICollection<Submission> Submissions { get; set; }
-
-		public Assignment()
+		public Exam()
 		{
 			Id = Guid.NewGuid();
 
+			ExamAttachments = new HashSet<ExamAttachment>();
 			Submissions = new HashSet<Submission>();
-			AssignmentClasses = new HashSet<AssignmentClass>();
-			AssignmentAttachments = new HashSet<AssignmentAttachment>();
 		}
 	}
 
 
-	public static class AssignmentExt
+	public static class examExt
 	{
-		public static Submission ConvertToSubmission(this Assignment assignment, Guid studentId, Guid GraderId)
+		public static Submission ConvertToSubmission(this Exam exam, Guid studentId, Guid GraderId, Guid classId)
 		{
-			if (assignment == null) return new Submission();
+			if (exam == null) return new Submission();
 			var submission = new Submission();
 
 			submission.StudentId = studentId;
 			submission.SubmissionTime = DateTime.Now;
 			submission.Status = SubmissionStatus.Pending;
 			submission.GraderId = GraderId;
-			submission.AssignmentId = assignment.Id;
-
-			ConvertExamSturctToSubmissionDetails(assignment.ExamStruct, studentId, submission.SubmissionDetails);
+			submission.ExamId = exam.Id;
+			submission.ClassId = classId;
+			ConvertExamSturctToSubmissionDetails(exam.ExamStruct, studentId, submission.SubmissionDetails);
 
 			return submission;
 		}
 
 
-		public static void ConvertExamSturctToSubmissionDetails(AssignmentQuestion examStruct, Guid studentId, ICollection<SubmissionDetail> submissions)
+		public static void ConvertExamSturctToSubmissionDetails(ExamQuestion examStruct, Guid studentId, ICollection<SubmissionDetail> submissions)
 		{
 			if (examStruct == null) return;
 			submissions.Add(new SubmissionDetail
 			{
 				StudentId = studentId,
-				AssignmentQuestionId = examStruct.Id,
-				IsCorrect = true,
+				ExamQuestionId = examStruct.Id,
 				CreatedAt = DateTime.Now,
 				UpdatedAt = DateTime.Now,
-				Status = SubmissionStatus.Pending,
 			});
 
-			examStruct.ChildrenAssignmentQuestion?.ToList().ForEach(s =>
+			examStruct.ChildExamQuestions?.ToList().ForEach(s =>
 			{
 				ConvertExamSturctToSubmissionDetails(s, studentId, submissions);
 			});

Entities/Contracts/ExamAttachment.cs

@@ -9,17 +9,18 @@ using System.Diagnostics.CodeAnalysis;
 
 namespace Entities.Contracts
 {
-	[Table("assignment_attachments")]
-	public class AssignmentAttachment
+	[Table("exam_attachments")]
+	public class ExamAttachment
 	{
 		[Key]
 		[Column("id")]
 		public Guid Id { get; set; }
 
 		[Required]
-		[Column("assignment_id")]
-		[ForeignKey("Assignment")]
-		public Guid AssignmentId { get; set; }
+		[Column("exam_id")]
+		public Guid ExamId { get; set; }
+		[ForeignKey(nameof(ExamId))]
+		public virtual Exam Exam { get; set; }
 
 		[Required]
 		[Column("file_path")]
@@ -37,10 +38,7 @@ namespace Entities.Contracts
 		[Column("deleted")]
 		public bool IsDeleted { get; set; }
 
-		// Navigation Properties
-		public Assignment Assignment { get; set; }
-
-		public AssignmentAttachment()
+		public ExamAttachment()
 		{
 			Id = Guid.NewGuid();
 		}

Entities/Contracts/ExamQuestion.cs

@@ -0,0 +1,71 @@
+using System.ComponentModel.DataAnnotations.Schema;
+using System.ComponentModel.DataAnnotations;
+using Entities.DTO;
+
+namespace Entities.Contracts
+{
+	[Table("exam_questions")]
+	public class ExamQuestion
+	{
+		[Key]
+		[Column("id")]
+		public Guid Id { get; set; }
+
+		[Column("title")]
+		[MaxLength(1024)]
+		public string? Title { get; set; }
+
+		[Column("question_id")]
+		public Guid? QuestionId { get; set; }
+		[ForeignKey(nameof(QuestionId))]
+		public virtual Question? Question { get; set; }
+
+		[Column("description")]
+		public Guid? QuestionContextId { get; set; }
+		[ForeignKey(nameof(QuestionContextId))]
+		public virtual QuestionContext? QuestionContext { get; set; }
+
+		[Required]
+		[Column("question_number")]
+		public byte Index { get; set; }
+
+		[Column("sequence")]
+		public string Sequence { get; set; } = string.Empty;
+
+		[Column("parent_question_group_id")]
+		public Guid? ParentExamQuestionId { get; set; }
+		[ForeignKey(nameof(ParentExamQuestionId))]
+		public virtual ExamQuestion? ParentExamQuestion { get; set; }
+
+		public Guid QuestionTypeId { get;set; }
+		[ForeignKey(nameof(QuestionTypeId))]
+		public virtual QuestionType Type { get; set; }
+
+		[Column("created_at")]
+		public DateTime CreatedAt { get; set; }
+
+		[Column("exam_struct_type")]
+		public ExamStructType ExamStructType { get; set; }
+		
+		[Column("score")]
+		public float? Score { get; set; }
+
+		[Column("deleted")]
+		public bool IsDeleted { get; set; }
+
+
+		public virtual Exam? Exam { get; set; }
+
+
+		[InverseProperty(nameof(SubmissionDetail.ExamQuestion))]
+		public virtual ICollection<SubmissionDetail> SubmissionDetails { get; set; }
+		[InverseProperty(nameof(ParentExamQuestion))]
+		public virtual ICollection<ExamQuestion> ChildExamQuestions { get; set; } = new List<ExamQuestion>();
+
+		public ExamQuestion()
+		{
+			Id = Guid.NewGuid();
+			SubmissionDetails = new HashSet<SubmissionDetail>();
+		}
+	}
+}

Entities/Contracts/ExamType.cs

@@ -0,0 +1,30 @@
+using System;
+using System.ComponentModel.DataAnnotations;
+using System.ComponentModel.DataAnnotations.Schema;
+
+namespace Entities.Contracts
+{
+    [Table("exam_type")]
+    public class ExamType
+	{
+        [Key]
+        [Column("id")]
+        public Guid Id { get; set; }
+
+        [Column("name")]
+        [MaxLength(20)]
+        public string Name { get; set; }
+
+        [Column("description")]
+        public string Description { get; set; }
+
+        [InverseProperty(nameof(Exam.ExamType))]
+        public virtual ICollection<Exam> Exams { get; set; }
+
+        public ExamType()
+        {
+			Id = Guid.NewGuid();
+			Exams = new HashSet<Exam>();
+        }
+    }
+}

Entities/Contracts/Global.cs

@@ -1,24 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.ComponentModel.DataAnnotations.Schema;
-using System.ComponentModel.DataAnnotations;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
-
-namespace Entities.Contracts
-{
-	[Table("global")]
-	public class Global
-	{
-		[Key]
-		[Column("id")]
-		public Guid Id { get; set; } = Guid.NewGuid();
-
-		public SubjectAreaEnum Area { get; set; }
-
-		public string Info { get; set; } = string.Empty;
-	}
-
-
-}

Entities/Contracts/Grade.cs

@@ -10,24 +10,25 @@ namespace Entities.Contracts
     {
         [Key]
         [Column("grade_id")]
-        public int GradeId { get; set; }
+        public Guid Id { get; set; }
 
         [Column("school_id")]
-        public int SchoolId { get; set; }
-        public School School { get; set; }
+        public Guid SchoolId { get; set; }
+        public virtual School School { get; set; }
 
         [Column("grade_name")]
         [MaxLength(20)]
         public string GradeName { get; set; }
 
         [Column("grade_level")]
-        public int GradeLevel { get; set; }
+        public byte GradeLevel { get; set; }
 
-        // Navigation Properties
-        public ICollection<Class> Classes { get; set; }
+        [InverseProperty(nameof(Class.Grade))]  
+        public virtual ICollection<Class> Classes { get; set; }
 
         public Grade()
         {
+            Id = Guid.NewGuid();
             Classes = new HashSet<Class>();
         }
     }

Entities/Contracts/Question.cs

@@ -24,35 +24,38 @@ namespace Entities.Contracts
 		[MaxLength(65535)]
 		public string? Answer { get; set; }
 
-
-
 		[Required]
 		[Column("type")]
-		[MaxLength(20)]
-		public QuestionType Type { get; set; } = QuestionType.Unknown;
-
-		[Column("difficulty_level")]
-		[MaxLength(10)] 
-		public DifficultyLevel DifficultyLevel { get; set; } = DifficultyLevel.easy;
+		public Guid QuestioTypeId { get; set; }
+		[ForeignKey(nameof(QuestioTypeId))]
+		public virtual QuestionType QuestionType { get; set; }
 
 		[Column("subject_area")]
-		public SubjectAreaEnum SubjectArea { get; set; } = SubjectAreaEnum.Unknown;
-
-		public string QType { get; set; } = string.Empty;
-
-		[Column("options")]
-		public string? Options { get; set; }
+		public Guid SubjectId { get; set; }
+		[ForeignKey(nameof(SubjectId))]
+		public virtual Subject Subject { get; set; }
 
 		[Column("key_point")]
 		public Guid? KeyPointId { get; set; }
+		[ForeignKey(nameof(KeyPointId))]
+		public virtual KeyPoint? KeyPoint { get; set; }
 
 		[Column("lesson")]
 		public Guid? LessonId { get; set; }
+		[ForeignKey(nameof(LessonId))]
+		public virtual Lesson? Lesson { get; set; }
 
-		
-		[Required]
-		[Column("created_by")]
-		public Guid CreatorId { get; set; }
+		//[Required]
+		//[Column("created_by")]
+		//public Guid CreatorId { get; set; }
+		//[ForeignKey(nameof(CreatorId))]
+		//public virtual User Creator { get; set; }
+
+		//[Column("difficulty_level")]
+		//public DifficultyLevel DifficultyLevel { get; set; } = DifficultyLevel.easy;
+
+		[Column("options")]
+		public string? Options { get; set; }
 
 		[Column("created_at")]
 		public DateTime CreatedAt { get; set; }
@@ -63,22 +66,13 @@ namespace Entities.Contracts
 		[Column("deleted")]
 		public bool IsDeleted { get; set; }
 
-
-		// Navigation Properties
-		[ForeignKey(nameof(CreatorId))]
-		public User Creator { get; set; }
-
-		[ForeignKey(nameof(KeyPointId))]
-		public KeyPoint? KeyPoint { get; set; }
-		[ForeignKey(nameof(LessonId))]	
-		public Lesson? Lesson { get; set; }
-		
-		public ICollection<AssignmentQuestion>? AssignmentQuestions { get; set; }
+		[InverseProperty(nameof(ExamQuestion.Question))]
+		public virtual ICollection<ExamQuestion>? ExamQuestions { get; set; }
 
 		public Question()
 		{
 			Id = Guid.NewGuid();
-			AssignmentQuestions = new HashSet<AssignmentQuestion>();
+			ExamQuestions = new HashSet<ExamQuestion>();
 		}
 	}
 

Entities/Contracts/QuestionContext.cs

@@ -13,13 +13,13 @@ namespace Entities.Contracts
 
 		public string Description { get; set; } = string.Empty;
 
-		[InverseProperty(nameof(AssignmentQuestion.QuestionContext))]	
-		public ICollection<AssignmentQuestion>? Questions { get; set; } = new List<AssignmentQuestion>();
+		[InverseProperty(nameof(ExamQuestion.QuestionContext))]	
+		public virtual ICollection<ExamQuestion>? Questions { get; set; } = new List<ExamQuestion>();
 
 
 		public QuestionContext()
 		{
-			Questions = new HashSet<AssignmentQuestion>();
+			Questions = new HashSet<ExamQuestion>();
 		}
 	}
 }

Entities/Contracts/QuestionType.cs

@@ -0,0 +1,40 @@
+using System;
+using System.ComponentModel.DataAnnotations;
+using System.ComponentModel.DataAnnotations.Schema;
+
+namespace Entities.Contracts
+{
+    [Table("question_types")]
+    public class QuestionType
+    {
+        [Key]
+        [Column("id")]
+        public Guid Id { get; set; }
+
+        [Column("name")]
+        [MaxLength(20)]
+        public string Name { get; set; }
+
+        [Column("subject_id")]
+        public Guid SubjectId { get; set; }
+        [ForeignKey(nameof(SubjectId))]
+        public virtual Subject Subject { get; set; }
+
+        [Column("description")]
+        public string Description { get; set; }
+
+        [Column("score_rule")]
+        [MaxLength(20)]
+        public string ScoreRule { get; set; }
+
+        [InverseProperty(nameof(Question.QuestionType))]
+        public virtual IEnumerable<Question> Questions { get; set; }
+
+        public QuestionType()
+        {
+            Id = Guid.NewGuid();
+
+			Questions = new HashSet<Question>();
+		}
+	}
+}

Entities/Contracts/School.cs

@@ -9,8 +9,8 @@ namespace Entities.Contracts
     public class School
     {
         [Key]
-        [Column("school_id")]
-        public int SchoolId { get; set; }
+        [Column("id")]
+        public Guid Id { get; set; }
 
         [Column("school_name")]
         [MaxLength(50)]
@@ -23,11 +23,12 @@ namespace Entities.Contracts
         [Column("create_time")]
         public DateTime CreateTime { get; set; }
 
-        // Navigation Properties
-        public ICollection<Grade> Grades { get; set; }
+        [InverseProperty(nameof(Grade.School))]
+        public virtual ICollection<Grade> Grades { get; set; }
 
         public School()
         {
+            Id = Guid.NewGuid();
             Grades = new HashSet<Grade>();
             CreateTime = DateTime.Now;
         }

Entities/Contracts/Subject.cs

@@ -0,0 +1,36 @@
+using System;
+using System.ComponentModel.DataAnnotations;
+using System.ComponentModel.DataAnnotations.Schema;
+
+namespace Entities.Contracts
+{
+    [Table("subjects")]
+    public class Subject
+    {
+        [Key]
+        [Column("id")]
+        public Guid Id { get; set; }
+
+        [Column("name")]
+        [MaxLength(20)]
+        public string Name { get; set; }
+
+        [Column("description")]
+        public string Description { get; set; }
+
+        [InverseProperty(nameof(QuestionType.Subject))]
+        public virtual IEnumerable<QuestionType> QuestionTypes { get; set; }
+
+        [InverseProperty(nameof(Question.Subject))]
+        public virtual IEnumerable<Question> Questions { get; set; }
+
+        [InverseProperty(nameof(User.TeachSubject))]
+        public virtual IEnumerable<User> SubjectTeachers { get; set; }
+        public Subject()
+        {
+            Id = Guid.NewGuid();
+            QuestionTypes = new HashSet<QuestionType>();
+			Questions = new HashSet<Question>();
+		}
+    }
+}

Entities/Contracts/Submission.cs

@@ -17,18 +17,30 @@ namespace Entities.Contracts
 		public Guid Id { get; set; }
 
 		[Required]
-		[Column("assignment_id")]
-		[ForeignKey("Assignment")]
-		public Guid AssignmentId { get; set; }
+		[Column("exam_id")]
+		public Guid ExamId { get; set; }
+		[ForeignKey(nameof(ExamId))]
+		public virtual Exam Exam { get; set; }
 
 		[Required]
 		[Column("student_id")]
-		[ForeignKey("Student")]
 		public Guid StudentId { get; set; }
+		[ForeignKey(nameof(StudentId))]
+		public virtual User Student { get; set; }
+
+		[Column("graded_by")]
+		public Guid? GraderId { get; set; }
+		[ForeignKey(nameof(GraderId))]
+		public virtual User Grader { get; set; }
+
+		[Column("class_id")]
+		public Guid ClassId { get; set; }
+		[ForeignKey(nameof(ClassId))]
+		public virtual Class Class { get; set; }
 
 		[Required]
 		[Column("attempt_number")]
-		public byte AttemptNumber { get; set; }
+		public byte AttemptNumber { get; set; }  // 第几次提交
 
 		[Column("submission_time")]
 		public DateTime SubmissionTime { get; set; }
@@ -39,31 +51,36 @@ namespace Entities.Contracts
 		[Column("overall_feedback")]
 		public string? OverallFeedback { get; set; }
 
-		[Column("graded_by")]
-		[ForeignKey("Grader")]
-		public Guid? GraderId { get; set; }
-
 		[Column("graded_at")]
 		public DateTime? GradedAt { get; set; }
 
-		[Column("deleted")]
-		public bool IsDeleted { get; set; }
-
-		public byte TotalQuesNum { get; set; }
-
-		public byte ErrorQuesNum { get; set; }
-
-		public byte TotalScore { get; set; }
-
 		[Required]
 		[Column("status")]
 		public SubmissionStatus Status { get; set; }
 
+		[Column("deleted")]
+		public bool IsDeleted { get; set; }
 		// Navigation Properties
-		public Assignment Assignment { get; set; }
-		public User Student { get; set; }
-		public User Grader { get; set; }
-		public ICollection<SubmissionDetail> SubmissionDetails { get; set; }
+
+		[NotMapped]
+		public int ErrorCount => SubmissionDetails.Where(sd => sd?.IsCorrect == false && sd.IsCorrect != null).Count();
+
+		[NotMapped]
+		public Dictionary<string, int> ErrorQuestionTypeDistribution => SubmissionDetails
+			.Where(sd => sd?.IsCorrect == false)
+			.GroupBy(sd => sd.ExamQuestion.Type.Name)
+			.ToDictionary(g => g.Key, g => g.Count());
+
+		[NotMapped]
+		public Dictionary<string, int> ErrorQuestionLessonDistribution => SubmissionDetails
+			.Where(sd => sd?.IsCorrect == false && sd.ExamQuestion.Question?.Lesson != null)
+			.GroupBy(sd => sd.ExamQuestion.Question.Lesson.Title)
+			.ToDictionary(g => g.Key, g => g.Count());
+
+
+
+		[InverseProperty(nameof(SubmissionDetail.Submission))]
+		public virtual ICollection<SubmissionDetail> SubmissionDetails { get; set; }
 
 		public Submission()
 		{

Entities/Contracts/SubmissionDetail.cs

@@ -20,15 +20,20 @@ namespace Entities.Contracts
 		[Column("submission_id")]
 		[ForeignKey("Submission")]
 		public Guid SubmissionId { get; set; }
+		[ForeignKey(nameof(SubmissionId))]
+		public virtual Submission Submission { get; set; }
 
 		[Required]
 		[Column("student_id")]
 		public Guid StudentId { get; set; }
+		[ForeignKey(nameof(StudentId))]
+		public virtual User Student { get; set; }
 
 		[Required]
-		[Column("assignment_question_id")]
-		[ForeignKey("AssignmentQuestion")]
-		public Guid AssignmentQuestionId { get; set; }
+		[Column("exam_question_id")]
+		public Guid ExamQuestionId { get; set; }
+		[ForeignKey(nameof(ExamQuestionId))]
+		public virtual ExamQuestion ExamQuestion { get; set; }
 
 		[Column("student_answer")]
 		public string? StudentAnswer { get; set; }
@@ -37,7 +42,7 @@ namespace Entities.Contracts
 		public bool? IsCorrect { get; set; }
 
 		[Column("points_awarded")]
-		public float? PointsAwarded { get; set; } // score
+		public float? PointsAwarded { get; set; } // 得分
 
 		[Column("teacher_feedback")]
 		public string? TeacherFeedback { get; set; }
@@ -51,20 +56,6 @@ namespace Entities.Contracts
 		[Column("deleted")]
 		public bool IsDeleted { get; set; }
 
-		[Required]
-		[Column("status")]
-		public SubmissionStatus Status { get; set; }
-
-
-
-		[ForeignKey(nameof(StudentId))]
-		public User Student { get; set; }
-
-		[ForeignKey(nameof(SubmissionId))]
-		public Submission Submission { get; set; }
-
-		[ForeignKey(nameof(AssignmentQuestionId))]
-		public AssignmentQuestion AssignmentQuestion { get; set; }
 
 		public SubmissionDetail()
 		{

Entities/Contracts/Textbook/KeyPoint.cs

@@ -18,14 +18,14 @@ namespace Entities.Contracts
 		public string Key { get; set; } = string.Empty;
 
 		
+
 		[Required]
 		public Guid LessonID { get; set; }
-
 		[ForeignKey(nameof(LessonID))]
-		public Lesson Lesson { get; set; }
+		public virtual Lesson Lesson { get; set; }
 
 
-		public ICollection<Question> Questions { get; set; }
+		public virtual ICollection<Question> Questions { get; set; }
 
 		public KeyPoint()
 		{

Entities/Contracts/Textbook/Lesson.cs

@@ -21,19 +21,19 @@ namespace Entities.Contracts
 
 		[Required]
 		public Guid TextbookID { get; set; }
-
-
 		[ForeignKey(nameof(TextbookID))]
-		public Textbook Textbook { get; set; }
+		public virtual Textbook Textbook { get; set; }
+
+
 
 		[InverseProperty(nameof(KeyPoint.Lesson))]
-		public ICollection<KeyPoint>? KeyPoints { get; set; }
+		public virtual ICollection<KeyPoint>? KeyPoints { get; set; }
 
 		[InverseProperty(nameof(Question.Lesson))]
-		public ICollection<Question>? Questions { get; set; }
+		public virtual ICollection<Question>? Questions { get; set; }
 
 		[InverseProperty(nameof(LessonQuestion.Lesson))]
-		public ICollection<LessonQuestion>? LessonQuestions { get; set; } 
+		public virtual ICollection<LessonQuestion>? LessonQuestions { get; set; } 
 
 
 

Entities/Contracts/Textbook/LessonQuestion.cs

@@ -19,9 +19,9 @@ namespace Entities.Contracts
 
 		[Required]
 		public Guid LessonID { get; set; }
-
 		[ForeignKey(nameof(LessonID))]	
-		public Lesson Lesson { get; set; }
+		public virtual Lesson Lesson { get; set; }
+
 
 		public LessonQuestion()
 		{

Entities/Contracts/Textbook/Textbook.cs

@@ -24,7 +24,7 @@ namespace Entities.Contracts
 		public SubjectAreaEnum SubjectArea { get; set; } = SubjectAreaEnum.Unknown;
 
 		[InverseProperty(nameof(Lesson.Textbook))]
-		public ICollection<Lesson> Lessons { get; set; }
+		public virtual ICollection<Lesson> Lessons { get; set; }
 
 		public Textbook()
 		{

Entities/Contracts/User.cs

@@ -3,47 +3,57 @@ using System.ComponentModel.DataAnnotations.Schema;
 
 namespace Entities.Contracts
 {
-	public enum UserRoles 
-	{
-		Student,
-		Teacher,
-		Administrator
-	}
 
 	public class User : IdentityUser<Guid>
 	{
 		public string? RefreshToken { get; set; }
+
 		public DateTime? RefreshTokenExpiryTime { get; set; }
-		public string? Address { get; set; }	
+		
+		public string? HomeAddress { get; set; }
+
 		public string? DisplayName { get; set; }
-		public SubjectAreaEnum SubjectArea { get; set; } = SubjectAreaEnum.Unknown;
+
+		public UserRoles? Role { get; set; } 
+
+		public Guid? TeachSubjectId { get; set; }
+		[ForeignKey(nameof(TeachSubjectId))]
+		public virtual Subject? TeachSubject { get; set; }
 
 		[Column("deleted")]
 		public bool IsDeleted { get; set; }
+		
+		[InverseProperty(nameof(ClassUser.User))]
+		public virtual ICollection<ClassUser> UserInjoinedClass { get; set; }
 
-		[InverseProperty(nameof(ClassTeacher.Teacher))]
-		public ICollection<ClassTeacher> TaughtClassesLink { get; set; }
-		[InverseProperty(nameof(ClassStudent.Student))]
-		public ICollection<ClassStudent> EnrolledClassesLink { get; set; }
+		//[InverseProperty(nameof(Question.Creator))]
+		//public virtual ICollection<Question> CreatedQuestions { get; set; }
+
+		[InverseProperty(nameof(Exam.Creator))]
+		public virtual ICollection<Exam> CreatedExams { get; set; }
+
+		[InverseProperty(nameof(SubmissionDetail.Student))]
+		public virtual ICollection<SubmissionDetail> SubmissionDetails { get; set; }
+
+		[InverseProperty(nameof(Submission.Student))]
+		public virtual ICollection<Submission> StudentSubmissions { get; set; }
+
+		[InverseProperty(nameof(Submission.Grader))]
+		public virtual ICollection<Submission> GradedSubmissions { get; set; }
 
-		public ICollection<Question> CreatedQuestions { get; set; }
-		public ICollection<Assignment> CreatedAssignments { get; set; }
 
-		public ICollection<SubmissionDetail> SubmissionDetails { get; set; }
-		public ICollection<Submission> SubmissionsAsStudent { get; set; }
-		public ICollection<Submission> GradedSubmissions { get; set; }
 
 		public User()
 		{
 			Id = Guid.NewGuid();
 			SecurityStamp = Guid.NewGuid().ToString();
 
-			CreatedQuestions = new HashSet<Question>();
-			TaughtClassesLink = new HashSet<ClassTeacher>();
-			EnrolledClassesLink = new HashSet<ClassStudent>();
-			CreatedAssignments = new HashSet<Assignment>();
+			//CreatedQuestions = new HashSet<Question>();
+			UserInjoinedClass = new HashSet<ClassUser>();
+			CreatedExams = new HashSet<Exam>();
 			GradedSubmissions = new HashSet<Submission>();
-			SubmissionsAsStudent = new HashSet<Submission>();
+			StudentSubmissions = new HashSet<Submission>();
+			SubmissionDetails = new HashSet<SubmissionDetail>();
 		}
 	}
 }