test三轮完成的版本，并入了国伟的班级模块

dao/wl_score_dao.py

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+from sqlalchemy.orm import Session
+from sqlalchemy import select, update, delete
+from model.wl_score_model import Score
+from model.wl_student_model import Student
+
+
+def get_score(db: Session, stu_id: int, exam_order: int):
+    """根据学生id+考试批次查询单条成绩"""
+    stmt = select(Score).where(
+        Score.stu_id == stu_id,
+        Score.exam_order == exam_order
+    )
+    return db.scalar(stmt)
+
+
+def get_student_by_id(db: Session, stu_id: int):
+    """检测学生是否存在：通过学生id查学生表"""
+    return db.scalar(select(Student).where(Student.stu_id == stu_id))
+
+
+def get_student_by_name(db: Session, stu_name: str):
+    """通过学生姓名查询学生"""
+    return db.scalar(select(Student).where(Student.stu_name == stu_name))
+
+
+def list_score_by_stu_id(db: Session, stu_id: int):
+    """查询一个学生全部成绩，返回列表"""
+    stmt = select(Score).where(Score.stu_id == stu_id)
+    return db.scalars(stmt).all()
+
+
+
+def create_score(db: Session, stu_id: int, exam_order: int, score: float):
+    """
+    新增成绩
+    返回：成功返回StudentScore对象；检测不通过返回None
+    """
+    # 1.检测：学生是否真实存在学生表
+    stu = get_student_by_id(db, stu_id)
+    if not stu:
+        print("[检测] 学生表无此学生,stu_id=", stu_id)
+        return None
+
+    # 2.检测：该学生该批次成绩是否已经存在（重复新增）
+    exist_score = get_score(db, stu_id, exam_order)
+    if exist_score:
+        print("[检测] 成绩已存在 stu_id=", stu_id, "exam_order=", exam_order)
+        return None
+
+    # 3.构建ORM对象插入数据库
+    new_score = Score(
+        stu_id=stu_id,
+        exam_order=exam_order,
+        score=score
+    )
+    db.add(new_score)
+    db.commit()
+    db.refresh(new_score)
+    return new_score
+
+
+
+def update_score(db: Session, stu_id: int, exam_order: int, new_score: float):
+    """
+    更新指定学生指定考试批次的分数
+    """
+    # 1.检测学生是否存在
+    stu = get_student_by_id(db, stu_id)
+    if not stu:
+        print("[检测] 更新失败：学生不存在")
+        return None
+
+    # 2.检测这条成绩记录本身是否存在
+    score_obj = get_score(db, stu_id, exam_order)
+    if not score_obj:
+        print("[检测] 更新失败：该学生该批次成绩记录不存在")
+        return None
+
+    # 方案A：直接修改对象属性（推荐）
+    score_obj.score = new_score
+    db.commit()
+    db.refresh(score_obj)
+    return score_obj
+
+
+
+
+
+def delete_score(db: Session, stu_id: int, exam_order: int):
+    """删除某个学生某一次考核成绩"""
+    # 检测记录是否存在
+    score_obj = get_score(db, stu_id, exam_order)
+    if not score_obj:
+        print("[检测] 删除失败，记录不存在")
+        return False
+
+    stmt = delete(Score).where(
+        Score.stu_id == stu_id,
+        Score.exam_order == exam_order
+    )
+    db.execute(stmt)
+    db.commit()
+    return True
+
+