将 Postgresql 添加到我的 Heroku 应用程序 - 语法崩溃查询的问题？

Question

我正在自学 Python、Flask，并将 Postgresql 添加到组合中。我最近在 Heroku 上部署了我的第一个应用程序，它根本不使用数据库，但现在我想添加功能。然而，我被困在这个过程中感觉非常简单的一步。请记住，我对 postgres 非常非常陌生。我在本地主机数据库上通过 MySQL 使所有这些功能完美运行，但无法在 Postgres 中远程运行:(

我的 check_connection() 有效，我的 create_table() 有效，但我的 pg_add_data() 失败，如您在底部看到的那样。我正在 PyCharm CE 中进行所有编码。

import psycopg2

# connect to remote Heroku Postgres DB
pgdb = psycopg2.connect(
   host='ec2-54-211-160-34.compute-1.amazonaws.com',
   user='xxxxxxxx',
   password='xxxxxxxxxxxxxxxxxxxxxxxx',
   port='5432',
   database='df5p5d20v6pbf9'
   )

pgcursor = pgdb.cursor()

# verify I've got my credentials in correctly
def check_connection():
   pgcursor.execute("select version()")
   data = pgcursor.fetchone()
   print("Connection established to: ", data)

def create_table():
   sql = '''CREATE TABLE estimation_data 
   (User text PRIMARY KEY,
    Motor_kV integer,
     Batt_Volt decimal,
      Pinion integer,
       Spur integer,
        Final_Gearing decimal,
         Wheel_Rad decimal);'''
   pgcursor.execute(sql)
   pgdb.commit()

def pg_add_data(sql,val):
   pgcursor.executemany(sql, val)
   pgdb.commit()

pgsql = '''INSERT INTO estimation_data 
   (User, Motor_kV, Batt_Volt, Pinion, Spur, Final_Ratio, Wheel_Rad) 
   VALUES (%s, %s, %s, %s, %s, %s, %s);'''
pgval = [
      ('204.210.165.122', 2400, 16.8, 16, 54, 3.92, 2.5),
      ('204.210.165.123', 3500, 12.6, 16, 54, 3.92, 2.5),
      ('204.210.165.124', 4200, 8.4, 12, 54, 3.92, 2.5)]

pg_add_data(pgsql,pgval)

当我执行底部的 pg_add_data 行时，我得到：

Traceback (most recent call last):
  File "C:\Users\prodsupervisor\PycharmProjects\RC_Speed_Estimator\db_handling.py", line 119, in <module>
    pg_add_data(pgsql,pgval)
  File "C:\Users\prodsupervisor\PycharmProjects\RC_Speed_Estimator\db_handling.py", line 96, in pg_add_data
    pgcursor.executemany(sql, val)
psycopg2.errors.SyntaxError: syntax error at or near "User"
LINE 2:    (User, Motor_kV, Batt_Volt, Pinion, Spur, Final_Ratio, Wh...
            ^


Process finished with exit code 1

我试图破译 User.... 处或附近有什么语法错误的答案。我被难住了。我一直在尝试按照教程 https://www.tutorialspoint.com/python_data_access/python_postgresql_insert_data.htm with the help of https://www.postgresqltutorial.com/ 进行操作。我也安装了 pgAdmin4，但在我学习的这个阶段我对那个程序感到困惑（到目前为止我更喜欢 MySQL Workbench）。

非常感谢所有帮助和提示！

编辑 1：根据 charchit 的建议，尝试在列名周围使用“”，结果如下：

Traceback (most recent call last):
  File "C:\Users\prodsupervisor\PycharmProjects\RC_Speed_Estimator\db_handling.py", line 119, in <module>
    pg_add_data(pgsql,pgval)
  File "C:\Users\prodsupervisor\PycharmProjects\RC_Speed_Estimator\db_handling.py", line 96, in pg_add_data
    pgcursor.executemany(sql, val)
psycopg2.errors.UndefinedColumn: column "User" of relation "estimation_data" does not exist
LINE 2:    (`User`, `Motor_kV`, `Batt_Volt`, `Pinion`, `Spur`, `Fina...
            ^


Process finished with exit code 1

Answer 1

User 是 postgresql 中的保留字，通过用 "" 括起来进行转义参见。与转义字符为反引号的 mysql 相反。

您还尝试插入名为 Final_Ratio 的列，但定义了一个列 Final_Gearing。为了测试，我还删除并重新创建了 table 每个运行。固定码：

import psycopg2

# connect to remote Heroku Postgres DB
pgdb = psycopg2.connect(
   host='localhost',
   user='test',
   password='test',
   port='5432',
   database='test_Whosebug'
   )

pgcursor = pgdb.cursor()

# verify I've got my credentials in correctly
def check_connection():
   pgcursor.execute("select version()")
   data = pgcursor.fetchone()
   print("Connection established to: ", data)

def create_table():
   sql = '''CREATE TABLE estimation_data 
   ("User" text PRIMARY KEY,
    Motor_kV integer,
     Batt_Volt decimal,
      Pinion integer,
       Spur integer,
        Final_Gearing decimal,
         Wheel_Rad decimal);'''
   pgcursor.execute(sql)
   pgdb.commit()

def drop_table():
   sql = "DROP TABLE IF EXISTS estimation_data;"
   pgcursor.execute(sql)
   pgdb.commit()



def pg_add_data(sql,val):
   pgcursor.executemany(sql, val)
   pgdb.commit()


check_connection()
drop_table()
create_table()

pgsql = '''INSERT INTO estimation_data 
   ("User", Motor_kV, Batt_Volt, Pinion, Spur, Final_Gearing, Wheel_Rad) 
   VALUES (%s, %s, %s, %s, %s, %s, %s);'''
pgval = [
      ('204.210.165.122', 2400, 16.8, 16, 54, 3.92, 2.5),
      ('204.210.165.123', 3500, 12.6, 16, 54, 3.92, 2.5),
      ('204.210.165.124', 4200, 8.4, 12, 54, 3.92, 2.5)]
pg_add_data(pgsql, pgval)

虽然学习生产站点的基础知识很好，但我强烈建议使用像 SQLalchemy 这样的高级库。

将 Postgresql 添加到我的 Heroku 应用程序 - 语法崩溃查询的问题？

Adding Postgresql to my Heroku app - issues with syntax crashing queries?

python

postgresql

heroku

flask