Scrapy INSERT in „new_table' nur, wenn in „aktueller Tabelle' kein Datensatz vorhanden ist

Question

Ich habe es mit Website-Scraping versucht. Ich habe die Daten erfolgreich aus der aktuellen Datenbanktabelle gelöscht. Aber ich möchte „new_table“ nur einfügen, wenn der Datensatz nicht in der „aktuellen Tabelle“ existiert

Mein Code ist (Pipeline)

table = 'products'
table2 = 'new_products'`
def save(self, row): 

    
    cursor = self.cnx.cursor()
    cursor.execute("SELECT DISTINCT product_id FROM products;")
    old_ids = [row[0] for row in cursor.fetchall()]
    create_query = ("INSERT INTO " + self.table + 
        "(rowid, date, listing_id, product_id, product_name, price, url) "
        "VALUES (%(rowid)s, %(date)s, %(listing_id)s, %(product_id)s, %(product_name)s, %(price)s, %(url)s)")

    cursor.execute(create_query, row)
    lastRecordId = cursor.lastrowid

    self.cnx.commit()
    cursor.close()
    print("Item saved with ID: {}" . format(lastRecordId))

    if not product_id in old_ids:
        create_query = ("INSERT INTO " + self.table2 + 
            "(rowid, date, listing_id, product_id, product_name, price, url) "
            "VALUES (%(rowid)s, %(date)s, %(listing_id)s, %(product_id)s, %(product_name)s, %(price)s, %(url)s)")

Es funktioniert nicht richtig und es liegt ein Fehler vor.

2022-05-06 12:26:57 [scrapy.core.scraper] ERROR: Error processing {'date': '2022-05-06 12:26:57.575507',
 'listing_id': '0190199600119',
 'price': '4199.00',
 'product_id': '1209298',
 'product_name': 'APPLE 11" Magic Türkçe Q Klavye Siyah',
 'rowid': 456274953331128512,
 'url': 'https://www.mediamarkt.com.tr/tr/product/APPLE%2011%22%20Magic%20T%C3%BCrk%C3%A7e%20Q%20Klavye%20Siyah-1209298.html'}
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/twisted/internet/defer.py", line 654, in _runCallbacks
    current.result = callback(current.result, *args, **kw)
  File "/usr/local/lib/python3.8/dist-packages/scrapy/utils/defer.py", line 162, in f
    return deferred_from_coro(coro_f(*coro_args, **coro_kwargs))
  File "/root/teknosa/teknosa/pipelines.py", line 28, in process_item
    self.save(dict(item))
  File "/root/teknosa/teknosa/pipelines.py", line 62, in save
    if not product_id in old_ids:
NameError: name 'product_id' is not defined
Saving item into db ...

Ich habe eine eindeutige Produkt-ID.

Wenn in der aktuellen Tabelle keine Produkt-ID vorhanden ist, fügen Sie diese Produkt-ID in „neue_Produkte“ ein

Wie macht man das?

Vielen Dank.

Letzte Änderung: Ich erhalte diese Fehlermeldung.

2022-05-07 18:17:11 [scrapy.core.scraper] ERROR: Error processing {'date': '2022-05-07 18:17:11.902622',
 'listing_id': '8713439219357',
 'price': '99.00',
 'product_id': '1175529',
 'product_name': 'TRUST 21935 NANGA USB 3.1 Kart Okuyucu',
 'rowid': -411152717288573423,
 'url': 'https://www.mediamarkt.com.tr/tr/product/TRUST%2021935%20NANGA%20USB%203.1%20Kart%20Okuyucu-1175529.html'}
Traceback (most recent call last):
  File "/usr/local/lib/python3.8/dist-packages/mysql/connector/connection_cext.py", line 523, in cmd_query
    self._cmysql.query(query,
_mysql_connector.MySQLInterfaceError: Duplicate entry '-411152717288573423' for key 'products.rowid'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/twisted/internet/defer.py", line 654, in _runCallbacks
    current.result = callback(current.result, *args, **kw)
  File "/usr/local/lib/python3.8/dist-packages/scrapy/utils/defer.py", line 162, in f
    return deferred_from_coro(coro_f(*coro_args, **coro_kwargs))
  File "/root/teknosa/teknosa/pipelines.py", line 28, in process_item
    self.save(dict(item))
  File "/root/teknosa/teknosa/pipelines.py", line 69, in save
    cursor.execute(create_query, row)
  File "/usr/local/lib/python3.8/dist-packages/mysql/connector/cursor_cext.py", line 269, in execute
    result = self._cnx.cmd_query(stmt, raw=self._raw,
  File "/usr/local/lib/python3.8/dist-packages/mysql/connector/connection_cext.py", line 528, in cmd_query
    raise errors.get_mysql_exception(exc.errno, msg=exc.msg,
mysql.connector.errors.IntegrityError: 1062 (23000): Duplicate entry '-411152717288573423' for key 'products.rowid'

Answer 1

如果您只想在不存在的情况下插入，则无需执行您正在执行的操作。无需全选然后查看您要查找的那个是否存在。

您需要的是为表2中的produc_id创建一个唯一索引

然后将代码更改为：

table = 'products'
table2 = 'new_products'`

def save(self, row):  
    create_query = ("INSERT INTO " + self.table + 
        "(rowid, date, listing_id, product_id, product_name, price, url) "
        "VALUES (%(rowid)s, %(date)s, %(listing_id)s, %(product_id)s, %(product_name)s, %(price)s, %(url)s)")

    cursor.execute(create_query, row)
    lastRecordId = cursor.lastrowid

    self.cnx.commit()
    print("Item saved with ID: {}" . format(lastRecordId))
    create_query = ("INSERT INTO " + self.table2 + 
            "(rowid, date, listing_id, product_id, product_name, price, url) "
            "VALUES (%(rowid)s, %(date)s, %(listing_id)s, %(product_id)s, %(product_name)s, %(price)s, %(url)s) ON DUPLICATE KEY UPDATE product_id=product_id")
    cursor.execute(create_query, row)
    self.cnx.commit()

如果您使用ON DUPLICATE KEY，当它发现重复行（已存在的product_id）时，系统会尝试将product_id更新为相同的product_id，因此不会生效。

如果设置 autocommit= True，则可以删除这些提交。

编辑

如果正如您在评论中所说，仅当表中不存在时才需要插入新表，您可以像这样更改代码：

您需要更改行 old_ids = [row[0] for row incursor.fetchall()] 中的变量名称，因为您正在更改 row 参数的值 2.你的问题出在if语句中，product_id变量不存在，需要修改

table = 'products'
table2 = 'new_products'`

def save(self, row):     
    cursor = self.cnx.cursor()
    cursor.execute("SELECT DISTINCT product_id FROM products;")
    old_ids = [element[0] for element in cursor.fetchall()]
    create_query = ("INSERT INTO " + self.table + 
        "(rowid, date, listing_id, product_id, product_name, price, url) "
        "VALUES (%(rowid)s, %(date)s, %(listing_id)s, %(product_id)s, %(product_name)s, %(price)s, %(url)s)")

    cursor.execute(create_query, row)
    lastRecordId = cursor.lastrowid

    self.cnx.commit()
    cursor.close()
    print("Item saved with ID: {}" . format(lastRecordId))

 

   if not row['product_id'] in old_ids:
        create_query = ("INSERT INTO " + self.table2 + 
            "(rowid, date, listing_id, product_id, product_name, price, url) "
            "VALUES (%(rowid)s, %(date)s, %(listing_id)s, %(product_id)s, %(product_name)s, %(price)s, %(url)s)")