python下SQlite数据库练习实例

python下SQlite数据库练习实例

# -*- coding:utf-8 -*-

import sqlite3
connect = sqlite3.connect('test.db')
cursor = connect.cursor()

# 1,创建一个学生成绩表 Grades，学号  姓名  成绩  名次
sql = 'CREATE TABLE Grades(num INTEGER PRIMARY KEY, name TEXT, grade INTEGER, rank INTEGER )'
# cursor.execute(sql)

# 2，往表中插入10数据
sql = 'INSERT INTO Grades(num,name,grade,rank) VALUES(8,"吼吼",50,89)'
# cursor.execute(sql)
# connect.commit()

# 3，查询成绩大于60分的人的名字
sql = 'SELECT name,grade FROM Grades WHERE grade > 60'
# rs = cursor.execute(sql)
# for x in rs:
#     print(x)

# 4，查询成绩小于60分的人的个数
sql = 'SELECT COUNT(*) FROM Grades WHERE grade < 60'
# rs = cursor.execute(sql)
# for x in rs:
#     print(x)
# connect.commit()

# 5，把成绩小于60分的人的成绩修改为60分
sql = 'UPDATE Grades SET grade = 60 WHERE grade < 60'
# cursor.execute(sql)
# connect.commit()

# 6，删除所有学号小于100的人的信息
sql = 'DELETE FROM Grades WHERE num < 100'
# cursor.execute(sql)
# connect.commit()

# 7，查询姓“张”的人的所有信息
sql = 'SELECT * FROM Grades WHERE name LIKE "张%"'
# rs = cursor.execute(sql)
# for x in rs:
#     print(x)
# connect.commit()

# 8，查询所有人的成绩，按照成绩从高到低排列
sql = 'SELECT grade FROM Grades ORDER BY grade DESC'
# rs = cursor.execute(sql)
# for x in rs:
#     print(x)
# connect.commit()

# 9，查询所有人的成绩，按照名次从小到大排列
sql = 'SELECT rank FROM Grades ORDER BY rank ASC'
# rs = cursor.execute(sql)
# for x in rs:
#     print(x)
# connect.commit()

# 关闭游标
cursor.close()
# # 关闭数据库连接
connect.close()