尝试使用 psycopg2.sql 在 python 中创建 Redshift 表

Question

我正在尝试使用 psycopg2 通过 python 在 redshift 中创建此表：

sql = "CREATE TABLE if not exists " + "<schema>.<tablename> " + \
      "( vendorid varchar(4), pickup_datetime TIMESTAMP, " + \
      "dropoff_datetime TIMESTAMP, store_and_fwd_flag varchar(1), " + \
      "ratecode int, pickup_longitude float(4), pickup_latitude float(4)," + \
      "dropoff_logitude float(4), dropoff_latitude float(4), " + \
      "passenger_count int, trip_distance float(40), fare_amount float(4), " + \
      "extra float(4), mta_tax float(4), tip_amount float(4), " + \
      "tolls_amount float(4), ehail_fee float(4), improvement_surcharge float(4), " + \
      "total_amount float(4), payment_type varchar(4), trip_type varchar(4))  " + \
      "DISTSTYLE EVEN SORTKEY (passenger_count, pickup_datetime);"

Schema.tablename 要通过命令行输入，所以我需要一个变量来保存 sys.arg[0]...但是如何使用 OR 我应该使用 psycopg2.sql 来构造它？？

Answer 1

如果我理解正确，您想在命令行上运行您的 python 脚本并传递几个参数，其中包括 Redshift 表的架构和表名。

您可以使用argparse库将命令行参数解析为变量，然后将它们连接成sql字符串：

import argparse

...

# ---------------------------------------------------------------------------------#
# Parse arguments
# ---------------------------------------------------------------------------------#
parser = argparse.ArgumentParser()
parser.add_argument("schema")
parser.add_argument("table")
args = parser.parse_args()
schema_name = args.schema
table_name = args.table

...

sql = "CREATE TABLE if not exists " + schema_name + "." + table_name + " " +\
  "( vendorid varchar(4), pickup_datetime TIMESTAMP, " + \
  "dropoff_datetime TIMESTAMP, store_and_fwd_flag varchar(1), " + \
  "ratecode int, pickup_longitude float(4), pickup_latitude float(4)," + \
  "dropoff_logitude float(4), dropoff_latitude float(4), " + \
  "passenger_count int, trip_distance float(40), fare_amount float(4), " + \
  "extra float(4), mta_tax float(4), tip_amount float(4), " + \
  "tolls_amount float(4), ehail_fee float(4), improvement_surcharge float(4), " + \
  "total_amount float(4), payment_type varchar(4), trip_type varchar(4))  " + \
  "DISTSTYLE EVEN SORTKEY (passenger_count, pickup_datetime);"
...

你可以像这样在命令行调用你的脚本：

python my_script.py myschema mytable