[英]Why my code python only can import some data from a file .CSV to my database PostgreSQL?
Description and Objective描述和目标
This is the project 1 of the CS50 Web programing's course.这是CS50 Web编程课程的项目1。 I need to import the content of a table from a file.csv to a table in my database PostgreSQL through Python.我需要通过 Python 将表中的内容从文件 csv 导入我的数据库 PostgreSQL 中的表。 The table has the next format:该表具有以下格式:
isbn,title,author,year
0380795272,Krondor: The Betrayal,Raymond E. Feist,1998
The columns of the table were created directly in my PostgreQSL database with the next data type:表的列是直接在我的 PostgreQSL 数据库中创建的,具有以下数据类型:
id: Integer not null
isbn: Varchar not null
title: Text not null
author: Varchar not null
year: Integer not null
I have the next Python code:我有下一个 Python 代码:
import csv
import os
from sqlalchemy import create_engine
from sqlalchemy.orm import scoped_session, sessionmaker
engine = create_engine(os.getenv("DATABASE_URL"))
db = scoped_session(sessionmaker(bind=engine))
def main():
f = open("bookspr1.csv")
reader = csv.reader(f)
for isbn, title, author, year in reader:
db.execute("INSERT INTO books (isbn, title, author, year) VALUES (:isbn, :title, :author, :year)",
{"isbn": isbn, "title": title, "author": author, "year": year})
print(f"Added the book {title}")
db.commit()
if __name__ == "__main__":
main()
Issue问题
When I run the python code to import the data table from the file.csv, the system throws an error:当我运行python代码从文件.csv导入数据表时,系统抛出错误:
C:\xampp\htdocs\project1>python import0_pr1A.py
Traceback (most recent call last):
File "C:\Users\Verel\AppData\Local\Programs\Python\Python37-32\lib\site-packag
es\sqlalchemy\engine\base.py", line 1284, in _execute_context
cursor, statement, parameters, context
File "C:\Users\Verel\AppData\Local\Programs\Python\Python37-32\lib\site-packag
es\sqlalchemy\engine\default.py", line 590, in do_execute
cursor.execute(statement, parameters)
psycopg2.errors.InvalidTextRepresentation: invalid input syntax for type integer
: "year"
LINE 1: ...le, author, year) VALUES ('isbn', 'title', 'author', 'year')
^
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File "import0_pr1A.py", line 24, in <module>
main()
File "import0_pr1A.py", line 18, in main
{"isbn": isbn, "title": title, "author": author, "year": year})
File "C:\Users\Verel\AppData\Local\Programs\Python\Python37-32\lib\site-packag
es\sqlalchemy\orm\scoping.py", line 163, in do
return getattr(self.registry(), name)(*args, **kwargs)
File "C:\Users\Verel\AppData\Local\Programs\Python\Python37-32\lib\site-packag
es\sqlalchemy\orm\session.py", line 1292, in execute
clause, params or {}
File "C:\Users\Verel\AppData\Local\Programs\Python\Python37-32\lib\site-packag
es\sqlalchemy\engine\base.py", line 1020, in execute
return meth(self, multiparams, params)
File "C:\Users\Verel\AppData\Local\Programs\Python\Python37-32\lib\site-packag
es\sqlalchemy\sql\elements.py", line 298, in _execute_on_connection
return connection._execute_clauseelement(self, multiparams, params)
File "C:\Users\Verel\AppData\Local\Programs\Python\Python37-32\lib\site-packag
es\sqlalchemy\engine\base.py", line 1139, in _execute_clauseelement
distilled_params,
File "C:\Users\Verel\AppData\Local\Programs\Python\Python37-32\lib\site-packag
es\sqlalchemy\engine\base.py", line 1324, in _execute_context
e, statement, parameters, cursor, context
File "C:\Users\Verel\AppData\Local\Programs\Python\Python37-32\lib\site-packag
es\sqlalchemy\engine\base.py", line 1518, in _handle_dbapi_exception
sqlalchemy_exception, with_traceback=exc_info[2], from_=e
File "C:\Users\Verel\AppData\Local\Programs\Python\Python37-32\lib\site-packag
es\sqlalchemy\util\compat.py", line 178, in raise_
raise exception
File "C:\Users\Verel\AppData\Local\Programs\Python\Python37-32\lib\site-packag
es\sqlalchemy\engine\base.py", line 1284, in _execute_context
cursor, statement, parameters, context
File "C:\Users\Verel\AppData\Local\Programs\Python\Python37-32\lib\site-packag
es\sqlalchemy\engine\default.py", line 590, in do_execute
cursor.execute(statement, parameters)
sqlalchemy.exc.DataError: (psycopg2.errors.InvalidTextRepresentation) invalid in
put syntax for type integer: "year"
LINE 1: ...le, author, year) VALUES ('isbn', 'title', 'author', 'year')
^
[SQL: INSERT INTO books (isbn, title, author, year) VALUES (%(isbn)s, %(title)s,
%(author)s, %(year)s)]
[parameters: {'isbn': 'isbn', 'title': 'title', 'author': 'author', 'year': 'yea
r'}]
(Background on this error at: http://sqlalche.me/e/9h9h)
C:\xampp\htdocs\project1>
In order to isolate the problem, I try to import the file.CSV but supriming the first row which include the names of the columns (isbn, title, author, year) and when I run the code, It starts the data transfer but It stops suddenly with another error when It try import a row where the data "title" or "author" contains Double quotes (" ") and Comma (,) .为了隔离问题,我尝试导入文件。CSV 但将包含列名称(isbn,title,author,year)的第一行放在首位,当我运行代码时,它开始数据传输,但它当它尝试导入数据“标题”或“作者”包含双引号(“”)和逗号(,)的行时突然停止并出现另一个错误。 For example the next row with the author "VE Schwab, Victoria Schwab" generate that conflict:例如,作者“VE Schwab, Victoria Schwab”的下一行会产生这种冲突:
0765335344,Vicious,"V.E. Schwab, Victoria Schwab",2013
And the new error is like this:新的错误是这样的:
C:\xampp\htdocs\project1>python import0_pr1A.py
Added the book The Mark of Athena
Added the book Her Fearful Symmetry
Traceback (most recent call last):
File "import0_pr1A.py", line 24, in <module>
main()
File "import0_pr1A.py", line 16, in main
for isbn, title, author, year in reader:
ValueError: not enough values to unpack (expected 4, got 1)
C:\xampp\htdocs\project1>python import0_pr1A.py
The data transfer is finished succesfully when the file.CSV is imported without the first row (isbn, title, author, year) and without data that contains Double quotes (" ") and Commas (,) .当文件.CSV 导入没有第一行(isbn,标题,作者,年份)并且没有包含双引号(“”)和逗号(,)的数据时,数据传输成功完成。
C:\xampp\htdocs\project1>python import0_pr1A.py
Added the book The Lion's Game
Added the book The Rainmaker
Added the book Eleanor & Park
C:\xampp\htdocs\project1>python import0_pr1A.py
C:\xampp\htdocs\project1>python list0_pr1.py
Krondor: The Betrayal by Raymond E. Feist of 1998.
The Dark Is Rising by Susan Cooper of 1973.
The Black Unicorn by Terry Brooks of 1987.
The Lion's Game by Nelson DeMille of 2000.
The Rainmaker by John Grisham of 1995.
Eleanor & Park by Rainbow Rowell of 2013.
C:\xampp\htdocs\project1>
Finally I tried inserting some code lines but the result was the same:最后我尝试插入一些代码行,但结果是一样的:
import psycopg2导入 psycopg2
reader.读者。 next下一个
db.close() db.close()
import csv
import os
import psycopg2
from sqlalchemy import create_engine
from sqlalchemy.orm import scoped_session, sessionmaker
engine = create_engine(os.getenv("DATABASE_URL"))
db = scoped_session(sessionmaker(bind=engine))
def main():
f = open("books.csv")
reader = csv.reader(f)
reader.__next__
for isbn, title, author, year in reader:
db.execute("INSERT INTO books (isbn, title, author, year) VALUES (:isbn, :title, :author, :year)",
{"isbn": isbn, "title": title, "author": author, "year": year})
print(f"Added the book {title}")
db.commit()
db.close()
if __name__ == "__main__":
main()
Conclusion I need a help to modify this python code that let me import completly the file.csv including the first row and the data that contains Double Quotes (" ") and Commas (,) .结论我需要帮助来修改这个 python 代码,让我完全导入文件。csv 包括第一行和包含双引号 (" ")和逗号 (,)的数据。
reader.__next__
This simply retrieves the method, it does not invoke the method.这只是检索方法,它不调用方法。 You need reader.__next__()
, but I think next(reader)
might be more conventional.您需要reader.__next__()
,但我认为next(reader)
可能更传统。
0765335344,Vicious,"V.E. Schwab, Victoria Schwab",2013
Works fine for me.对我来说很好。 Maybe your actual file has smart quotes or something like that rather than straight ASCII.也许您的实际文件有智能引号或类似的东西,而不是直接的 ASCII。
Try尝试
csv.reader(lines, quotechar='"', delimiter=',', ...
see csv.reader also prior SO answer,请参阅csv.reader 之前的 SO答案,
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