Question

我试图将CSV文件中的一行插入到Heroku网站上的Postgres数据库中，该代码访问该数据库，打开CSV文件并访问tha数据，而且还返回InvalidRequestError。

代码可以正确地从CSV文件中获取数据，我不知道自己在做什么错。

数据格式为CSV文件： 1416949658，《黑暗正在崛起》，苏珊·库珀，1973年

表结构：

CREATE TABLE books(
        id SERIAL PRIMARY KEY,
        isbn VARCHAR NOT NULL,                  
                title VARCHAR NOT NULL,
        author_name VARCHAR NOT NULL,
        publish_year INTEGER NOT NULL

);

for isbn, title, author_name, publish_year in reader:
    db.execute("INSERT INTO books (isbn, title, author_name, publish_year) VALUES (:isbn, :title, :author_name, :publish_year)",\
                {isbn: isbn, title: title, author_name: author_name, publish_year: publish_year})
    print(f"Added book {title} written by {author_name} with isbn {isbn} on year {publish_year}")
db.commit()

sqlalchemy.exc.StatementError：（sqlalchemy.exc.InvalidRequestError）A 绑定参数'isbn'所需的值[SQL：INSERT INTO书籍（isbn，标题，author_name，publish_year）VALUES（％（isbn）s，％（title）s，％（author_name）s，％（发布 _year）s）;]] [参数：[{'1416949658'：'1416949658'，'The Dark Is Rising'：'The Dark Is Rising'，'Susan Cooper'：'Susan Cooper'，' 1973'：'1973'}]]

如您所见，它获取数据，但仍然返回错误。

Answer 1

要从csv导入数据，请运行以下代码段

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("books.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 book of ISBN {isbn} having Title: {title} written by  {author} in the year {year}.")
    db.commit()


if __name__ == "__main__":
    main()

这应该可以解决您的问题。您缺少python中的字典需要提供的{"key": value}格式。

插入语句返回绑定参数<x>需要一个值

1 个答案: