Python使用sqlite3第三方库读写SQLite数据库的方法步骤

import pandas as pd
import sqlite3
# 利用pandas读取数据
student_df=pd.read_csv("./Dataset/student_grades.csv",encoding='utf-8-sig')

# 创建学生成绩数据库
conn=sqlite3.connect("./Database/Student_grade.db")
## 创建游标
cursor=conn.cursor()
## 创建成绩表
try:
    # 判断表是否存在, 存在则先删除
    dropif_sql='Drop TABLE IF EXISTS student_grades;'
    create_sql='''
        CREATE TABLE student_grades
        (
            studentID varchar(64),
            studentName varchar(64),
            scoreEnglish float(64),
            scoreChinese float(64),
            scoreMath float(64)
        )
    '''
    cursor.execute(dropif_sql)
    cursor.execute(create_sql)
except:
    print("Create table failed!")

# 将学生信息存入数据库
for i in range(student_df.shape[0]):
    print(student_df.loc[i,:].to_list())
    # 插入语句
    insert_sql='''
        INSERT INTO student_grades(studentID, studentName, scoreEnglish, scoreChinese, scoreMath)
        Values('%s','%s','%f','%f','%f')'''%(
            str(student_df.loc[i,'StudentID']),
            str(student_df.loc[i,'name']),
            student_df.loc[i,'english'],
            student_df.loc[i,'chinese'],
            student_df.loc[i,'math'],
        )
    # 执行语句
    cursor.execute(insert_sql)
    # 事物提交
    conn.commit()

# 录入李四的数学成绩
grade_LiSi=70
# 更新语句
update_sql='UPDATE student_grades SET scoreMath={} WHERE studentID=10002'.format(grade_LiSi)
# 执行语句
cursor.execute(update_sql)
# 事物提交
conn.commit()

# 查询录入李四成绩后的信息
select_sql='SELECT * FROM student_grades;'
# 执行语句
results=cursor.execute(select_sql)
# 遍历输出
for info in results.fetchall():
    print(info)

# 更新王五的数学成绩
grade_WangWu=85
# 更新语句
update_sql='UPDATE student_grades SET scoreMath={} WHERE studentID=10003'.format(grade_WangWu)
# 执行语句
cursor.execute(update_sql)
# 事物提交
conn.commit()

# 查询王五的成绩
select_sql='SELECT * FROM student_grades WHERE studentID=10003;'
# 执行语句
results=cursor.execute(select_sql)
# 遍历输出
for info in results.fetchall():
    print(info)

# 查询数据
select_sql='SELECT * FROM student_grades;'
# 执行语句
results=cursor.execute(select_sql)
# 计算各科平均分以及总分排名
english_lst=[]
chinese_lst=[]
math_lst=[]
total_dct={}
for info in results.fetchall():
    english_lst.append(info[2])
    chinese_lst.append(info[3])
    math_lst.append(info[4])
    total_dct[info[1]]=sum(info[2:])

# 计算平均分的函数
def average_score(lst):
    return round(sum(lst)/len(lst),2)

# 输出结果
print("英语平均分为:", average_score(english_lst))
print("语文平均分为:", average_score(chinese_lst))
print("数学平均分为:", average_score(math_lst))
print("总成绩排名为:", sorted(total_dct.items(), key=lambda x:x[1], reverse=True))