psycopg2.ProgrammingError: syntax error at or near "\"

Question

I have a python module which copy data from a table to a file.Im using postgresql as database server. COPY is the command is to be used to do the above action.

However in a blog (http://grokbase.com/t/postgresql/pgsql-general/058tagtped/about-error-must-be-superuser-to-copy-to-or-from-a-file) it states that, You can use \copy in 'psql' on the client side, but you have to be a superuser to do COPY on the server side, for security reasons. So I used \copy command. When I try to execute the below method, it results in error as

psycopg2.ProgrammingError: syntax error at or near "\" LINE 1: \copy

I can't find why its throwing error. can someone help me out?

def process():
     query="\copy %s TO %s"%('test_table', 'test_file.txt')

     @env.with_transaction()
     def do_execute(db):
         cursor = db.cursor()
         cursor.execute(query)

do_execute is a database wrapper, which creates connection and executes the query.

\copy is a command only recognized by the psql command line tool. It is not valid SQL. The command line tool most likely implements the command using several SQL constructs to load data then export it to a text file. — Martijn Pieters
– Martijn Pieters, Commented Aug 8, 2013 at 10:07
And for that valid SQL - you can find it at postgresql.org/docs/8.2/static/sql-copy.html — Jon Clements
– Jon Clements, Commented Aug 8, 2013 at 10:08
The same page states: If you are not using 'psql' and your client library supports it, you can use 'COPY FROM stdin' and pass the data across the client connection. — Martijn Pieters
– Martijn Pieters, Commented Aug 8, 2013 at 10:08
possible duplicate of Can not "COPY FROM" with Postgres & Python — Martijn Pieters
– Martijn Pieters, Commented Aug 8, 2013 at 10:11
@MartijnPieters If I replace the line query="\copy %s TO %s"%('test_table', 'test_file.txt') with query='pg_dump table_name > %s'%(txt_file), again I'm facing the same error. — Darknight
– Darknight, Commented Aug 8, 2013 at 11:39

Craig Ringer · Accepted Answer · 2013-08-08 13:38:43Z

6

\ is an escape in Python strings, so your string contains the escape \c. However \c is an invalid escape in Python, and Python leaves invalid escapes unchanged, so "\copy" is just \copy. (Thus @tiziano's answer is misleading).

>>> print "\c"
\c

The real problem is that \copy is a psql command, not a server side PostgreSQL command. You can't use it with a client other than psql. You must instead use the psycopg2 support for COPY to do it via your client driver.

answered Aug 8, 2013 at 13:38

Craig Ringer

329k84 gold badges742 silver badges820 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Darknight Over a year ago

@Craig.. Thanks for your explanation. I made the changes and make the script to run successfully

Collectives™ on Stack Overflow

psycopg2.ProgrammingError: syntax error at or near "\"

1 Answer 1

1 Comment

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Linked

Related