Add support for ./manage.py dbshell -c SQL

[Artem Skoretskiy]

At the moment you cannot run specific SQL directly with dbshell:

./manage.py dbshell -c "select * from auth_group"

You have to use pipes, that are not always convenient:

echo "select * from auth_group" | ./manage.py dbshell

If we add -c argument, it would be in sync with shell command, where you could provide commands already.

[Carlton Gibson]

This seems reasonable, at first glance at least. The trick will be to pass the command to each of the backend clients correctly, but there's no reason that's not possible right? Accepting on that basis. A PR is very welcome.

[Artem Skoretskiy]

It should be easy to implement since we don’t need to use database-specific backend

Something like that:

from django.db import connection

if command:
    cursor = connection.cursor()
    cursor.execute(command)
    # show `cursor.fetchall()` result

[Volodymyr Dmytriiev]

any progress on this one? Is the previously suggested approach good enough? If so, I'd love to give a try?

[Artem Skoretskiy]

No progress AKAIK.

Maybe it would be easier to call database-specific CLI tool with right parameters than run cursor.

Pros:

• No need to care about printing results (user could execute SELECT)
• Could run commands that are unique for the CLI (e.g. \dt to show tables in psql)

Cons:

• Each backend would need its own command to run (but we already have dbshell, so we know name of binary; just need a parameter to execute a query).
• Each backend would show results in its own format, so you cannot e. g. save result as cab file)

Another completely different approach would be to pass all command line arguments provided to dbshell, e.g. after “—“ divider to database CLI app. For example:

./manage.py dbshell — -c “select * from auth_user”

[Adam Johnson]

I don't think opening a cursor is the right way. My mental model of dbshell is that it always passes through to the underlying tool, which can have subtle implications on even what SQL/commands are accepted.

I am actually most in favour of passing all arguments through after a -- divider as that is the most flexible.

[introquest]

​https://github.com/django/django/pull/10186

[Tim Graham]

"Ready for checkin" is set by a patch reviewer. And the patch isn't ready for review without tests and documentation.

[David Vaz]

So the PR is closed due to missing Tests and Documentation. Does anybody care that I take this?
I could make a PR based on the original one and add tests and docs

[Claude Paroz]

Absolutely, feel free to work on issues obviously stalled. Just credit original patch writers if appropriate.

[Adam Johnson]

​PR

[Mariusz Felisiak <felisiak.mariusz@…>]

In 8189976:

Refs #29501 -- Added test for missing dbshell executable.

[Mariusz Felisiak <felisiak.mariusz@…>]

In 8bd9000:

Refs #29501 -- Made dbshell catch more specific FileNotFoundError.

[Mariusz Felisiak <felisiak.mariusz@…>]

In 6cad9116:

Refs #29501 -- Simplified BaseCommand.run_from_argv() a bit.

[Mariusz Felisiak <felisiak.mariusz@…>]

In 8e8c3f96:

Refs #29501 -- Allowed customizing exit status for management commands.

[Adam Johnson <me@…>]

In 5b884d45:

Fixed #29501 -- Allowed dbshell to pass options to underlying tool.