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  • SQLite数据库

    SQLite3 of python

    一、SQLite3 数据库

      SQLite3 可使用 sqlite3 模块与 Python 进行集成,一般 python 2.5 以上版本默认自带了sqlite3模块,因此不需要用户另外下载。

    描述

      Python的数据库模块有统一的接口标准,所以数据库操作都有统一的模式(假设数据库模块名为db):

      1. 用db.connect创建数据库连接,假设连接对象为conn

      2. 如果该数据库操作不需要返回结果,就直接使用conn.execute查询,根据数据库事物隔离级别的不同,可能修改数据库需要conn.commit

      3. 如果需要返回查询结果则用conn.cursor创建游标对象cur,通过cur.execute查询数据库,cursor方法有fetchall、fetchone、fetchmany返回查询结果,根据数据库事物隔离级别不同,可能修改数据库需要coon.commit

      4. 关闭cur.close

    基本操作实例如下:

    #coding=utf-8
    
    import sqlite3
    
    conn = sqlite3.connect("sqlite.db")  #创建sqlite.db数据库
    print ("open database success")
    conn.execute("drop table IF EXISTS student")
    query = """create table IF NOT EXISTS student(
        customer VARCHAR(20),
        produce VARCHAR(40),
        amount FLOAT,
        date DATE   
    );"""
    conn.execute(query)
    print ("Table created successfully")
    
    #在表中插入数据
    
    ''' 方法1 '''
    #data = '''INSERT INTO student(customer,produce,amount,date)
    #    VALUES("zhangsan","notepad",999,"2017-01-02")'''
    #conn.execute(data)
    #data = '''INSERT INTO student(customer,produce,amount,date)
    #    VALUES("lishi","binder",3.45,"2017-04-05")'''
    #conn.execute(data)
    #conn.commit()
    
    ''' 方法2 '''
    statement = "INSERT INTO student VALUES(?,?,?,?)"
    data = [("zhangsan","notepad",999,"2017-01-02"),("lishi","binder",3.45,"2017-04-05")]
    conn.executemany(statement, data)
    conn.commit()
    
    curson = conn.execute("select * from student")
    conn.commit()
    print (curson)
    rows = curson.fetchall()
    print (rows)
    conn.close()

    Python爬取大学排名,直接上代码吧

    # -*- coding: utf-8 -*-
    """
    Created on Wed May 29 22:44:12 2019
    
    @author: guo'yu'yi
    """
    
    import sqlite3
    from pandas import DataFrame
    import re
    class SQL_method:
        def __init__(self, dbName, tableName, data, columns, COLUMNS, Read_All=True):
            self.dbName = dbName
            self.tableName = tableName
            self.data = data
            self.columns = columns
            self.COLUMNS = COLUMNS
            self.Read_All = Read_All
        def creatTable(self):
            connect = sqlite3.connect(self.dbName)
            connect.execute("CREATE TABLE {}({})".format(self.tableName, self.columns))
            connect.commit()
            connect.close()
        def insertDataS(self):
            connect = sqlite3.connect(self.dbName)
            connect.executemany("INSERT INTO {} VALUES(?,?,?,?,?,?,?,?,?,?,?,?,?)".format(self.tableName), self.data)
            connect.commit()
            connect.close()
        def searchData(self, conditions, IfPrint=True):
            connect = sqlite3.connect(self.dbName)
            cursor = connect.cursor()
            cursor.execute("SELECT * FROM {} WHERE {}".format(self.tableName, conditions))
            data = cursor.fetchall()
            cursor.close()
            connect.close()
            if IfPrint:
                self.printData(data)
            return data
        def printData(self, data):
            print("{1:{0}^3}{2:{0}<11}{3:{0}<4}{4:{0}<4}{5:{0}<5}{6:{0}<5}{7:{0}^5}{8:{0}^5}{9:{0}^5}{10:{0}^5}{11:{0}^5}{12:{0}^6}{13:{0}^5}".format(chr(12288), *self.COLUMNS))
            for i in range(len(data)):
                print("{1:{0}<4.0f}{2:{0}<10}{3:{0}<5}{4:{0}<6}{5:{0}<7}{6:{0}<8}{7:{0}<7.0f}{8:{0}<8}{9:{0}<7.0f}{10:{0}<6.0f}{11:{0}<9.0f}{12:{0}<6.0f}{13:{0}<6.0f}".format(chr(12288), *data[i]))
        def getAllData(self):
            connect = sqlite3.connect(self.dbName)
            cursor = connect.cursor()
            cursor.execute("SELECT * FROM {}".format(self.tableName))
            dataList = cursor.fetchall()
            connect.close()
            return dataList
        def run(self):
            try:
                self.creatTable()
                print(">>> 数据库创建成功!")
                self.insertDataS()
                print(">>> 表创建、数据插入成功!")
            except:
                print(">>> 数据库已创建!")
            if self.Read_All:
                self.printData(self.getAllData())
        def deleteData(self, conditions):
            connect = sqlite3.connect(self.dbName)
            connect.execute("DELETE FROM {} WHERE {}".format(self.tableName, conditions))
            connect.commit()
            connect.close()
        def destroyTable(self):
            connect = sqlite3.connect(self.dbName)
            connect.execute("DROP TABLE {}".format(self.tableName))
            connect.commit()
            connect.close()
    def get_data(fileName):
        data = []
        f = open(fileName, 'r', encoding='utf-8')
        for line in f.readlines():
            line = line.replace('
    ', '')
            line = line.replace('%','')
            line = line.split(',')
            for i in range(len(line)):
                try:
                    if line[i] == '':
                        line[i] = '0'
                    line[i] = eval(line[i])
                except:
                    continue
            data.append(tuple(line))
        EN_columns = "Rank real, University text, Province text, Grade real, SourseQuality real, TrainingResult real, ResearchScale real, 
        ReserchQuality real, TopResult real, TopTalent real, TechnologyService real, Cooperation real, TransformationResults real"
        CH_columns =  ["排名", "学校名称", "省市", "总分", "生涯质量", "培养结果(%)", "科研规模", "科研质量", "顶尖成果", "顶尖人才", "科技服务", "产学研合作", "成果转化"]
        return data[1:], EN_columns, CH_columns
    if __name__ == "__main__":
        fileName = "D:\python文件\daxuepaimingRank.csv"
        data, EN_columns, CH_columns = get_data(fileName)
        dbName = "db24.db"
        tableName = "university"
        SQL = SQL_method(dbName, tableName, data, EN_columns, CH_columns, False)
        SQL.run()
        print("
    查找数据项(University = '汕头大学') :")
        SQL.searchData("University = '汕头大学'", True)
        print("
    按照科研规模排序(Province = '广东省') :")
        SQL.searchData("Province = '广东省' ORDER BY ResearchScale", True)
        Weight = [0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.40, 0.45, 0.5]
        value, sum = [], 0
        sample = SQL.searchData("Province = '广东省'", False)
        for i in range(len(sample)):
            for j in range(len(Weight)):
                sum += sample[i][4+j] * Weight[j]
            value.append(sum)
            sum=0
        university = [university[1] for university in sample]
        uv, tmp = [], []
        for i in range(len(university)):
            tmp.append(university[i])
            tmp.append(value[i])
            uv.append(tmp)
            tmp = []
        df = DataFrame(uv, columns=list(("大学", "总分")))
        df = df.sort_values('总分')
        df.index = [i for i in range(1, len(uv)+1)]
        print("
    通过权值运算后重排名的结果:
    ", df)
        SQL.deleteData("Province = '北京市'")
        SQL.deleteData("Province = '山东省'")
        SQL.deleteData("Province = '河南省'")
        SQL.deleteData("Province = '山西省'")
        SQL.deleteData("Province = '广东省'")
        SQL.deleteData("Province = '江西省'")
        print("
    数据删除成功")
        SQL.printData(SQL.getAllData())
        SQL.destroyTable()
        print("
    删除成功")

    结果如下

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  • 原文地址:https://www.cnblogs.com/gyy-15768200938/p/10947184.html
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