How to drop all tables from the database with mana

Question

How can I drop all tables from a database using manage.py and command line? Is there any way to do that executing manage.py with appropriate parameters so I can execute it from a .NET application?

Answer 1

Here's a south migration version of @peter-g's answer. I often fiddle with raw sql, so this comes in handy as 0001_initial.py for any befuddled apps. It will only work on DBs that support SHOW TABLES (like mysql). Substitute something like SELECT table_name FROM information_schema.tables WHERE table_schema = 'public'; if you use PostgreSQL. Also, I often do this exact same thing for both the forwards and backwards migrations.

from south.db import db
from south.v2 import SchemaMigration
from django.db.utils import DatabaseError
from os import path
from logging import getLogger
logger = getLogger(__name__)


class Migration(SchemaMigration):

    def forwards(self, orm):

        app_name = path.basename(path.split(path.split(path.abspath(__file__))[0])[0])
        table_tuples = db.execute(r"SHOW TABLES;")

        for tt in table_tuples:
            table = tt[0]
            if not table.startswith(app_name + '_'):
                continue
            try:
                logger.warn('Deleting db table %s ...' % table)
                db.delete_table(table)
            except DatabaseError:
                from traceback import format_exc
                logger.error("Error running %s: \n %s" % (repr(self.forwards), format_exc()))

Coworker/cocoders would kill me if they knew I did this, though.

Answer 2

There's an even simpler answer if you want to delete ALL your tables. You just go to your folder containing the database (which may be called mydatabase.db) and right-click the .db file and push "delete." Old fashioned way, sure-fire to work.

Answer 3

This answer is for postgresql DB:

Run: echo 'drop owned by some_user' | ./manage.py dbshell

NOTE: some_user is the name of the user you use to access the database, see settings.py file:

default_database = {
    'ENGINE': 'django.db.backends.postgresql_psycopg2',
    'NAME': 'somedbname',
    'USER': 'some_user',
    'PASSWORD': 'somepass',
    'HOST': 'postgresql',
    'PORT': '',
}

Answer 4

There's no native Django management command to drop all tables. Both sqlclear and reset require an app name.

However, you can install Django Extensions which gives you manage.py reset_db, which does exactly what you want (and gives you access to many more useful management commands).

Answer 5

If you're using the South package to handle database migrations (highly recommended), then you could just use the ./manage.py migrate appname zero command.

Otherwise, I'd recommend the ./manage.py dbshell command, piping in SQL commands on standard input.

Answer 6

Drops all tables and recreates them:

python manage.py sqlclear app1 app2 appN | sed -n "2,$p" | sed -n "$ !p" | sed "s/";/" CASCADE;/" | sed -e "1s/^/BEGIN;/" -e "$s/$/COMMIT;/" | python manage.py dbshell
python manage.py syncdb

Explanation:

manage.py sqlclear - "prints the DROP TABLE SQL statements for the given app name(s)"

sed -n "2,$p" - grabs all lines except first line

sed -n "$ !p" - grabs all lines except last line

sed "s/";/" CASCADE;/" - replaces all semicolons (;) with (CASCADE;)

sed -e "1s/^/BEGIN;/" -e "$s/$/COMMIT;/" - inserts (BEGIN;) as first text, inserts (COMMIT;) as last text

manage.py dbshell - "Runs the command-line client for the database engine specified in your ENGINE setting, with the connection parameters specified in your USER, PASSWORD, etc., settings"

manage.py syncdb - "Creates the database tables for all apps in INSTALLED_APPS whose tables have not already been created"

Dependencies:

• sed, to use on Windows, I installed UnxUtils: (Download) (Installation Instructions)

---

Credits:

@Manoj Govindan and @Mike DeSimone for sqlclear piped to dbshell

@jpic for 'sed "s/";/" CASCADE;/"'