如何避免将数据复制到mysql

wb1gzix0 于 2021-07-29 发布在 Java

关注(0)|答案(3)|浏览(340)

我写代码从ebay.com上抓取汽车信息（标题、品牌、型号、传输、年份、价格）数据并保存在mysql中，如果所有行的（标题、品牌、型号等）项目与另一行相似，则避免将此数据插入mysql，*仅当所有行的项目相似时（因为某些标题相似或某些型号或…）
代码：

import requests
from bs4 import BeautifulSoup
import re
import mysql.connector

conn = mysql.connector.connect(user='root', password='******', 
host='127.0.0.1', database='web_scraping')
cursor = conn.cursor()
url = 'https://www.ebay.com/b/Cars-Trucks/6001?_ fsrp=0&_sacat=6001&LH_BIN=1&LH_ItemCondition=3000%7C1000%7C2500&rt=nc&_stpos=95125&Model%2520Year=2020%7C2019%7C2018%7C2017%7C2016%7C2015'
res = requests.get(url)
soup = BeautifulSoup(res.text, 'html.parser')
ebay_cars = soup.find_all('li', class_='s-item')
for car_info in ebay_cars:
    title_div = car_info.find('div', class_='s-item__wrapper clearfix')
    title_sub_div = title_div.find('div', class_='s-item__info clearfix')
    title_p = title_sub_div.find('span', class_='s-item__price')
    title_tag = title_sub_div.find('a', class_='s-item__link')
    title_maker = title_sub_div.find('span', class_='s-item__dynamic s- 
    item__dynamicAttributes1')
    title_model = title_sub_div.find('span', class_='s-item__dynamic s- 
    item__dynamicAttributes2')
    title_trans = title_sub_div.find('span', class_='s-item__dynamic s- 
    item__dynamicAttributes3')

name_of_car = re.sub(r'\d{4}', '', title_tag.text)
maker_of_car = re.sub(r'Make: ','', title_maker.text)
model_of_car = re.sub(r'Model: ', '', title_model.text)
try:
    if title_trans.text.startswith(r'Transmission: '):
        trans_of_car = re.sub(r'Transmission: ', '', title_trans.text)
    else:
        trans_of_car = ''
except AttributeError:
    trans_of_car = ''
year_of_car = re.findall(r'\d{4}', title_tag.text)
year_of_car = ''.join(str(x) for x in year_of_car)

price_of_car = title_p.text
print(name_of_car ,trans_of_car )
sql = 'INSERT INTO car_info(Title, Maker, Model, Transmission, Year, Price) 
VALUES (%s, %s, %s, %s, %s, %s)'
cursor.execute(sql , (name_of_car, maker_of_car, model_of_car, trans_of_car, 
year_of_car, price_of_car))

conn.commit()
conn.close()

sql python mariadb sql-update sql-insert

来源：https://stackoverflow.com/questions/62287128/how-avoid-dublicate-data-to-mysql

3条答案

按热度按时间

7gcisfzg1#

一个选项使用 not exists :

insert into car_info (title, maker, model, transmission, year, price) 
select v.*
from (select %s title, %s maker, %s model, %s transmission, %s year, %s price) v
where not exists (
    select 1
    from car_info c
    where 
        (c.title, c.maker, c.model, c.transmission, c.year, c.price)
         = (v.title, v.maker, v.model, v.transmission, v.year, v.price)
);

但在表的所有列上创建唯一键会更简单，如：

create unique index idx_car_info_uniq
    on car_info(title, maker, model, transmission, year, price);

这可以防止任何进程在表中插入重复项。你可以优雅地忽略错误，否则会提出与 on duplicate key 语法：

insert into car_info (title, maker, model, transmission, year, price) 
values (%s, %s, %s, %s, %s, %s)
on duplicate key update title = values(title);

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6rvt4ljy2#

您可以将此查询的结果保存到变量中

SELECT COUNT(*) FROM car_info WHERE Title = <titleValue>, Maker = <makerValue>, Model = <modelValue>, Transmission = <transmisionValue>, Year = <yearValue>, Price = <priceValue>

然后，如果变量的值
1，跳过insert，因为表中已有此条目
0，则进行插入，因为表中没有该条目
这只是一种方法。

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x0fgdtte3#

将主键声明为表中的所有列。请参见：https://www.mysqltutorial.org/mysql-primary-key/

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