Как использовать тип INET с Python и PostgreSQL?
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14-11-2019 - |
Вопрос
Я пишу программу Python3, которая использует базу данных PostgreSQL, я использую PY-PostgreSQL: http://python.projects.postgresql.org/ в качестве драйвера базы данных. Одна таблица хранит IP-адреса с использованием типа INET.
Я создал следующее подготовленное утверждение:
aID = db.prepare('SELECT id FROM a_records WHERE ip = $1 LIMIT 1')
.
При вызове помощи (IP) я получаю следующую ошибку:
(IP - это строка Python)
File "/usr/local/lib/python3.1/dist-packages/postgresql/driver/pq3.py", line
1517, in __call__
c = SingleXactFetch(self, parameters)
File "/usr/local/lib/python3.1/dist-packages/postgresql/driver/pq3.py", line
837, in __init__
Output.__init__(self, '')
File "/usr/local/lib/python3.1/dist-packages/postgresql/driver/pq3.py", line
622, in __init__
self._init()
File "/usr/local/lib/python3.1/dist-packages/postgresql/driver/pq3.py", line
854, in _init
STEP()
File "/usr/local/lib/python3.1/dist-packages/postgresql/driver/pq3.py", line
2612, in _pq_step
self.typio.raise_error(x.error_message, cause = getattr(x, 'exception', Non
e))
File "/usr/local/lib/python3.1/dist-packages/postgresql/driver/pq3.py", line
507, in raise_error
self.raise_server_error(error_message, **kw)
File "/usr/local/lib/python3.1/dist-packages/postgresql/driver/pq3.py", line
498, in raise_server_error
raise server_error
postgresql.exceptions.BinaryRepresentationError: invalid address family in exte
rnal "inet" value
CODE: 22P03
LOCATION: File 'network.c', line 218, in network_recv from SERVER
RESULT:
type: SingleXactFetch
parameters: ('139.78.113.1',)
STATEMENT: [prepared]
sql_parameter_types: ['pg_catalog.inet']
results: (id INTEGER)
statement_id: py:0x2ff9a50
string: SELECT id FROM a_records WHERE ip = $1 LIMIT 1
CONNECTION: [idle]
client_address: 127.0.0.1/32
client_port: 51563
version:
PostgreSQL 8.4.7 on x86_64-pc-linux-gnu, compiled by GCC gcc-4.4.real (Debi
an 4.4.5-8) 4.4.5, 64-bit
CONNECTOR: [IP4] pq://python:***@127.0.0.1:5432/vdz
category: None
DRIVER: postgresql.driver.pq3.Driver
.
Может кто-нибудь помочь мне отладить это и выяснить, почему PostgreSQL не любит данные INET?
Спасибо!
Решение
@mrlanrat, it's because the python library is sending your parameters as a TEXT data type but PostgreSQL is expecting an INET data type. Your example there changes the parameters so that PostgreSQL is expecting a TEXT data type, which it then casts in to an INET data type. I know that psycopg2 supports an INET data type but I'm pretty sure the current version of py-postgresql doesn't support the data type (as of 2011-05-19). Which means you have three options:
- py-postgresql needs to add support for the INET data type
- you get to pass in data of type TEXT and then cast it to INET on the server
- switch to psycopg2, which does support the INET data type.
Другие советы
I've been having this problem all day, and I could not find any solution, so obviously I found the solution on my own a few minutes after posting here.
I need to replace $1 with inet($1::varchar), it seems that postgresql does not like it being a string when converting to an inet value, and you must typecast it as a varchar, and then turn the value into an inet variable.
So, the working line is:
aID = db.prepare('SELECT id FROM a_records WHERE ip = inet($1::varchar) LIMIT 1')
Can anyone explain why this is, and why it wont work the way I tried to at first?
Thanks!
You should explicitly cast string to inet data type.
aID = db.prepare('SELECT id FROM a_records WHERE ip = inet($1) LIMIT 1')