I try to design a database schema and use alembic (and virtualenv if that matters). I made some CSV files with testdata. Currently I copy them into the db on the interactive postgresql shell via
/copy table_name FROM '~/path/to/file.csv' WITH CSV;
I would like to automate this so I don't have to manually copy every table when I grade down and up via alembic. I tried the following:
In my alembic version file in the upgrade() method, below the generation of my tables, I added:
op.execute("copy table_name FROM '~/path/to/file.csv' WITH CSV;", execution_options=None)
But it never finds the file. This is the error:
File "/Users/me/Workspace/project/venv/lib/python3.4/site-packages/SQLAlchemy-0.9.4-py3.4-macosx-10.6-intel.egg/sqlalchemy/engine/default.py", line 435, in do_execute
cursor.execute(statement, parameters)
sqlalchemy.exc.OperationalError: (OperationalError) could not open file "~/Workspace/project/path/to/file.csv" for reading: No such file or directory
"copy table_name FROM '~/Workspace/project/path/to/file.csv' WITH CSV;" {}
What am I doing wrong?
Is my problem that I try to run a postgresql command where I can use only sqlalchemy command? If so, how would I do this via sqlalchemy?
I know of the bulk import option in alembic but I would prefer to not re-format everything.
Are there other options to automate the copy operation? Are there better workflows?
Postgres does not run as "you" so the home directory will be different. When entering file paths in postgres, always use the full path to the file. In the case of doing this as part of an alembic upgrade, you should do something like:
import os
dirname = os.path.dirname(__file__)
filename = os.path.join(dirname, 'relative/path/to/file/you/want')
op.execute(f"copy table_name FROM '{file_name}' WITH CSV;", execution_options=None)
Related
I'm trying to import csv file's table into pgAdmin using COPY command and getting the error:
ERROR: could not open file "R:\myfile.csv" for reading: No such file or directory
HINT: COPY FROM instructs the PostgreSQL server process to read a file. You may want a client-side facility such as psql's \copy.
The statement is:
copy tst_copy from 'R:\myfile.csv'
I'm familiarizing myself with the standalone version of Datagrip and having a bit of trouble understanding the different approaches to composing SQL via console, external files, scratch files, etc.
I'm managing, referencing the documentation, and am happy to figure things out as such.
However, I'm trying to ingest CSV data into tables via batch files using the Postgres \copy command. Datagrip will execute this command without error but no data is being populated.
This is my syntax, composed and ran in the console view:
\copy tablename from 'C:\Users\username\data_file.txt' WITH DELIMITER E'\t' csv;
Note that the data is tab-separated and stored in a .txt file.
I'm able to use the import functions of Datagrip (via context menu) just fine but I'd like to understand how to issue commands to do similarly.
\copy is a command of the command-line PostgreSQL client psql.
I doubt that Datagrip invokes psql, so it won't be able to use \copy or any other “backslash command”.
You probably have to use Datagrip's import facilities. Or you start using psql.
Ok, but what about the SQL COPY command https://www.postgresql.org/docs/12/sql-copy.html ?
How can I run something like that with datagrip ?
BEGIN;
CREATE TEMPORARY TABLE temp_json(values text) ON COMMIT DROP;
COPY temp_json FROM 'MY_FILE.JSON';
SELECT values->>'aJsonField' as f
FROM (select values::json AS values FROM temp_json) AS a;
COMMIT;
I try to replace 'MY_FILE.JSON' with full path, parameter (?), I put it in sql directory etc.
The data grip answer is :
[2021-05-05 10:30:45] [58P01] ERROR: could not open file '...' for reading : No such file or directory
EDIT :
I know why. RTFM! -_-
COPY with a file name instructs the PostgreSQL server to directly read from or write to a file. The file must be accessible by the PostgreSQL user (the user ID the server runs as) and the name must be specified from the viewpoint of the server.
Sorry.....
I am trying to import a CSV file into postgresSQL, however, I keep getting the error that no such file exists or directory.
this is the line of code I execute copy mu_data from
copy mu_data from 'users/mysurname/Desktop/FILE.CSV' DELIMITER ',' CSV
HEADER;
Can anyone suggest how to fix this?
copy is a command run on the server side. So unless your Postgres server happens to be on your localhost, the file very likely doesn't exist from the view of the server.
So one solution is you to transfer the file to the servers filesystem somehow. Or, if you're using the psql command line tool (or at least can use it for this task), you can use the \copy command there.
I tried to make a variable in SQL statement in Postgresql, but it did not work.
There are many csv files stored under the path. I want to set path in Postgresql that can tell copy command where can find csv files.
SQL statement sample:
\set outpath '/home/clients/ats-dev/'
\COPY licenses (_id, name,number_seats ) FROM :outpath + 'licenses.csv' CSV HEADER DELIMITER ',';
\COPY uploaded_files (_id, added_date ) FROM :outpath + 'files.csv' CSV HEADER DELIMITER ',';
It did not work. I got error: no such files. The two files licneses.csv and files.csv are stored under /home/cilents/ats-dev on Ubuntu. I found some sultion that use "\set file 'license.csv'". It did not work for me becacuse I have many csv files. also I tried to use "from : outpath || 'licenses.csv'". it did not work ether. Appreciate for any helps.
Using 9.3.
It looks like psql does not support :variable substitution withinpsql backslash commands.
test=> \set somevar fred
test=> \copy z from :somevar
:somevar: No such file or directory
so you will need to do this via an external tool like the unix shell. e.g.
for f in *.sql; do
psql -c "\\copy $(basename $f) FROM '$f'"
done
You can try COPY command
\set outpath '\'/home/clients/ats-dev/'
COPY licenses (_id, name,number_seats ) FROM :outpath/licenses.csv' WITH CSV HEADER DELIMITER ',';
COPY uploaded_files (_id, added_date ) FROM :outpath/files.csv' WITH CSV HEADER DELIMITER ',';
Note: Files named in a COPY command are read or written directly by the server, not by the client application. Therefore, they must reside on or be accessible to the database server machine, not the client. They must be accessible to and readable or writable by the PostgreSQL user (the user ID the server runs as), not the client. Similarly, the command specified with PROGRAM is executed directly by the server, not by the client application, must be executable by the PostgreSQL user. COPY naming a file or command is only allowed to database superusers, since it allows reading or writing any file that the server has privileges to access.
Documentation: Postgresql 9.3 COPY
It may have been true when this was originally asked, that psql backslash commands didn't support variable interpolation, but in my PostgreSQL 14 instance that's no longer the case. However, the psql manpage is clear that \copy specifically does not support variable interpolation.
we can use
copy (select * from mytbl) to 'D:/products.csv' with csv header
to import data in mytbl to local disk D
so is it possible to use the same method to upload the file directly into a FTP-Server ?
i tried like this
copy (select * from mytbl) to 'ftp://usrname:mypasswrd#ftp.drivehq.com/masters/3/product/products.csv' with csv header
but got this error
ERROR: relative path not allowed for COPY to file
SQL state: 42602
using PostgreSQL 9.2
PostgreSQL does not support any source/destination for COPY other than a file or stdin/stdout.
What you can do is COPY to stdout and pipe that to a program that writes the data to the ftp dir. psql's \copy is useful for this:
psql -c "\copy mytable to stdout with (format csv, header)" | ncftpput -c my.ftp.host /path/on/host
You can use any tool that accepts the input data on a pipe to write to the remote ftp file; ncftpput is just one option.
A future PostgreSQL version may add support for invoking COPY with a pipe, e.g. COPY ... TO '|/some/command', but there are serious security concerns with running programs under the PostgreSQL user that would make this a superuser-only operation and of questionable safety even then. It's much safer to run the program client-side, and psql is ideal for that.