前言：
SQLite屬于輕型數據庫，遵守ACID的關系型數據庫管理系統，它包含在一個相對小的C庫中。在很多嵌入式產品中使用了它，它占用資源非常的低，python 中默認繼承了操作此款數據庫的引擎 sqlite3 說是引擎不如說就是數據庫的封裝版，開發自用小程序的使用使用它真的大贊
一、簡單操作SQLite數據庫
簡單操作SQLite數據庫:創建 sqlite數據庫是一個輕量級的數據庫服務器,該模塊默認集成在python中,開發小應用很不錯.
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import sqlite3# 數據表的創建conn = sqlite3.connect("data.db")cursor = conn.cursor()create = "create table persion(" \ "id int auto_increment primary key," \ "name char(20) not null," \ "age int not null," \ "msg text default null" \ ")"cursor.execute(create) # 執行創建表操作 |
1、簡單的插入語句的使用
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insert = "insert into persion(id,name,age,msg) values(1,'lyshark',1,'hello lyshark');"cursor.execute(insert)insert = "insert into persion(id,name,age,msg) values(2,'guest',2,'hello guest');"cursor.execute(insert)insert = "insert into persion(id,name,age,msg) values(3,'admin',3,'hello admin');"cursor.execute(insert)insert = "insert into persion(id,name,age,msg) values(4,'wang',4,'hello wang');"cursor.execute(insert)insert = "insert into persion(id,name,age,msg) values(5,'sqlite',5,'hello sql');"cursor.execute(insert)data = [(6, '王舞',8, 'python'), (7, '曲奇',8,'python'), (9, 'C語言',9,'python')]insert = "insert into persion(id,name,age,msg) values(?,?,?,?);"cursor.executemany(insert,data) |
2、簡單的查詢語句的使用
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select = "select * from persion;"cursor.execute(select)#print(cursor.fetchall()) # 取出所有的數據select = "select * from persion where name='lyshark';"cursor.execute(select)print(cursor.fetchall()) # 取出所有的數據select = "select * from persion where id >=1 and id <=2;"list = cursor.execute(select)for i in list.fetchall(): print("字段1：", i[0]) print("字段2：", i[1]) |
二、更新數據與刪除
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update = "update persion set name='蒼老師' where id=1;"cursor.execute(update)update = "update persion set name='蒼老師' where id>=1 and id<=3;"cursor.execute(update)delete = "delete from persion where id=3;"cursor.execute(delete)select = "select * from persion;"cursor.execute(select)print(cursor.fetchall()) # 取出所有的數據conn.commit() # 事務提交，每執行一次數據庫更改的操作，就執行提交cursor.close()conn.close() |
三、實現用戶名密碼驗證
當用戶輸入錯誤密碼后,自動鎖定該用戶1分鐘.
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import sqlite3import re,timeconn = sqlite3.connect("data.db")cursor = conn.cursor()"""create = "create table login(" \ "username text not null," \ "password text not null," \ "time int default 0" \ ")"cursor.execute(create)cursor.execute("insert into login(username,password) values('admin','123123');")cursor.execute("insert into login(username,password) values('guest','123123');")cursor.execute("insert into login(username,password) values('lyshark','1231');")conn.commit()"""while True: username = input("username:") # 這個地方應該嚴謹驗證,盡量不要讓用戶拼接SQL語句 password = input("passwor:") # 此處為了方便不做任何驗證(注意:永遠不要相信用戶的輸入) sql = "select * from login where username='{}'".format(username) ret = cursor.execute(sql).fetchall() if len(ret) != 0: now_time = int(time.time()) if ret[0][3] <= now_time: print("當前用戶{}沒有被限制,允許登錄...".format(username)) if ret[0][0] == username: if ret[0][1] == password: print("用戶 {} 登錄成功...".format(username)) else: print("用戶 {} 密碼輸入有誤..".format(username)) times = int(time.time()) + 60 cursor.execute("update login set time={} where username='{}'".format(times,username)) conn.commit() else: print("用戶名正確,但是密碼錯誤了...") else: print("賬戶 {} 還在限制登陸階段,請等待1分鐘...".format(username)) else: print("用戶名輸入錯誤") |
四、SQLite檢索時間記錄
通過編寫的TimeIndex函數檢索一個指定范圍時間戳中的數據.
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import os,time,datetimeimport sqlite3"""conn = sqlite3.connect("data.db")cursor = conn.cursor()create = "create table lyshark(" \ "time int primary key," \ "cpu int not null" \ ")"cursor.execute(create)# 批量生成一堆數據,用于后期的測試.for i in range(1,500): times = int(time.time()) insert = "insert into lyshark(time,cpu) values({},{})".format(times,i) cursor.execute(insert) conn.commit() time.sleep(1)"""# db = data.db 傳入數據庫名稱# table = 指定表lyshark名稱# start = 2019-12-12 14:28:00# ends = 2019-12-12 14:29:20def TimeIndex(db,table,start,ends): start_time = int(time.mktime(time.strptime(start,"%Y-%m-%d %H:%M:%S"))) end_time = int(time.mktime(time.strptime(ends,"%Y-%m-%d %H:%M:%S"))) conn = sqlite3.connect(db) cursor = conn.cursor() select = "select * from {} where time >= {} and time <= {}".format(table,start_time,end_time) return cursor.execute(select).fetchall()if __name__ == "__main__": temp = TimeIndex("data.db","lyshark","2019-12-12 14:28:00","2019-12-12 14:29:00") print(temp) |
五、SQLite提取數據并繪圖
通過使用matplotlib這個庫函數,并提取出指定時間的數據記錄,然后直接繪制曲線圖.
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import os,time,datetimeimport sqlite3import numpy as npfrom matplotlib import pyplot as pltdef TimeIndex(db,table,start,ends): start_time = int(time.mktime(time.strptime(start,"%Y-%m-%d %H:%M:%S"))) end_time = int(time.mktime(time.strptime(ends,"%Y-%m-%d %H:%M:%S"))) conn = sqlite3.connect(db) cursor = conn.cursor() select = "select * from {} where time >= {} and time <= {}".format(table,start_time,end_time) return cursor.execute(select).fetchall()def Display(): temp = TimeIndex("data.db","lyshark","2019-12-12 14:28:00","2019-12-12 14:29:00") list = [] for i in range(0,len(temp)): list.append(temp[i][1]) plt.title("CPU Count") plt.plot(list, list) plt.show() if __name__ == "__main__": Display() |
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原文鏈接：https://www.cnblogs.com/LyShark/p/12172674.html
