实训5 合并代码

import pymysql def connect_to_mysql(): try: # 数据库连接参数 connection pymysql.connect( hostlocalhost, # MySQL服务器地址 userroot, # 数据库用户名 passwordroot, # 数据库密码请替换为实际密码 databasetest_db, # 要连接的数据库名 charsetutf8mb4, # 支持中文 ) print(数据库连接成功) return connection except Exception as e: print(f数据库连接失败{e}) return None def insert_student(name, age, gender, grade): sql INSERT INTO students (name, age, gender, grade) VALUES (%s, %s, %s, %s) cursor.execute(sql, (name, age, gender, grade)) conn.commit() print(f成功插入学生{name}) def query_students(): sql SELECT * FROM students cursor.execute(sql) results cursor.fetchall() # print(results) print(查询结果) for row in results: print(fID: {row[0]}, 姓名: {row[1]}, 年龄: {row[2]}, 性别: {row[3]}, 成绩: {row[4]}) def delete_student(name): sql DELETE FROM students WHERE name %s affected_rows cursor.execute(sql, (name,)) conn.commit() if affected_rows 0: print(f成功删除学生{name}) else: print(f未找到学生 {name}) def update_student(name,new_grade): sql update students set grade %s where name %s affected_rows cursor.execute(sql,(new_grade,name)) conn.commit() if affected_rows 0: print(f成功更新学生{name}的成绩为{new_grade}) else: print(f未找到可以修改的学生{name}) # 主程序测试 if __name__ __main__: conn connect_to_mysql() try: with conn.cursor() as cursor: insert_student(赵六, 20, 女, 88.0) query_students() delete_student(赵六) update_student(李四,99.8) query_students() except Exception as e: print(f失败{e}) conn.rollback() finally: conn.close()