Python添加到MySQL数据库

Question

使用 Scrapy 获取一些东西，我想将其存储在数据库中。之前从未使用过 MySQL 或 Python 做过任何事情，因此需要寻求一些帮助来了解为什么这不起作用。

这是我的代码:

from __future__ import print_function
from metacritic.items import MetacriticItem
from mysql.connector import errorcode
import mysql.connector
import json

class MetacriticPipeline(object):

DB_NAME = 'metacritic'

TABLES = {}
TABLES['titles'] = (
    "CREATE TABLE `titles` ("
    "   `name` varchar (14) NOT NULL,"
    "   PRIMARY KEY (`emp_no`)"
    ")  ENGINE=InnoDB")

cnx = mysql.connector.connect(user='root', password = 'andy')
cursor = cnx.cursor()

def process_item(self, item, spider):
    if item['title']:
        return item

class JsonWriterPipeline(object):

def __init__(self):
    self.file = open('items.jl', 'wb')

def process_item(self, item, spider):
    line = json.dumps(dict(item)) + "\n"
    self.file.write(line)
    return item

class WriteToDatabasePipeline(object):

def create_database(cursor):
    try:
        cursor.execute(
            "CREATE DATABASE {} DEFAULT CHARACTER SET 'utf8'".format(DB_NAME))
    except mysql.connector.Error as err:
        print("Failed creating database: {}".format(err))
        exit(1)

try:
    cnx.database = DB_NAME
except mysql.connector.Error as err:
    if err.errno == errorcode.ER_BAD_DB_ERROR:
        create_database(cursor)
        cnx.database = DB_NAME
    else:
        print(err)
        exit(1)

当我尝试运行 CMD 时，出现此错误:

File "metacritic\pipelines.py", line 46, in WriteToDatabasePipeline
cnx.database = DB_NAME
NameError: name 'DB_NAME' is not defined

知道这是为什么吗？在我看来 DB_NAME 已经定义好了？我现在只想创建数据库，然后尝试添加表。感谢您的帮助

Answer 1

您正在 MetacriticPipeline 类中定义 DB_NAME，将其移动到脚本顶部(或者更好地移动到 scrapy 设置):

from __future__ import print_function
from metacritic.items import MetacriticItem
from mysql.connector import errorcode
import mysql.connector
import json

DB_NAME = 'metacritic'

class MetacriticPipeline(object):
   ...