wondering if there is more clearer information or a code snippet for this,
I am also struggling to use 2 databases (1 dev, 1 prod) in my alembic
project, I have successfully ran the migrations on the dev database, now I
want to run my migrations to the prod database, I have no idea on how to
modify alembic.ini and env.py file,,, please help
On Tuesday, 01 February 2022 at 15:08:20 UTC+2 skira....@gmail.com wrote:
> If you have git example, share, please.
> On Monday, 30 April 2012 at 04:10:14 UTC+3 limodou wrote:
>
>> On Sun, Apr 29, 2012 at 11:13 PM, Michael Bayer
>> <mik...@zzzcomputing.com> wrote:
>> >
>> > On Apr 29, 2012, at 10:56 AM, limodou wrote:
>> >
>> >> On Sun, Apr 29, 2012 at 10:42 PM, Michael Bayer
>> >> <mik...@zzzcomputing.com> wrote:
>> >>> You would assemble a multi-database scheme of your choosing in
>> env.py. If you do "alembic init multidb" you'll see an example of one.
>> How env.py is organized depends greatly on the relationship of the
>> databases to each other, that is, to what degree they are mirrors of each
>> other versus storing different schemas.
>> >>>
>> >>
>> >> If I ran the command:
>> >>
>> >> alembic init multidb
>> >>
>> >> It'll create multidb folder and copy files in it. But I saw the
>> >> alembic.ini will be the same one. So if I should change it myself? And
>> >> how to let alembic know different database when executing commands
>> >> like: revision, upgrade, etc. It seems that no database parameter
>> >> existed.
>> >>
>> >> And if I can manage different databases in one directory or in one ini
>> file?
>> >
>> > multidb has a different alembic.ini as an example. If you already had
>> an alembic.ini there it wouldn't overwrite it.
>> >
>> > if you really wanted two completely independent sets of migration
>> scripts, then you'd run two migration environments.
>> >
>> > They can share the same alembic.ini like this:
>> >
>> > [my_db_one]
>> > sqlalchemy.url =
>> >
>> > [my_db_two]
>> > sqlalchemy.url =
>> >
>> > you then run alembic with "alembic -n my_db_one" or "alembic -n
>> my_db_two". The "default" config area is set by -n.
>> >
>> > A single env.py script can get multiple database URLs in any way it
>> wants, as it determines how config is accessed. If you look in the
>> multidb/env.py script, you'll see it's pulling multiple database urls from
>> one section using config.get_section(name) - config file:
>> >
>> > [alembic]
>> > # path to migration scripts
>> > script_location = ${script_location}
>> >
>> > # template used to generate migration files
>> > # file_template = %%(rev)s_%%(slug)s
>> >
>> > databases = engine1, engine2
>> >
>> > [engine1]
>> > sqlalchemy.url = driver://user:pass@localhost/dbname
>> >
>> > [engine2]
>> > sqlalchemy.url = driver://user:pass@localhost/dbname2
>> >
>> > usage:
>> >
>> > config = context.config
>> >
>> > db_names = config.get_main_option('databases')
>> >
>> > for name in re.split(r',\s*', db_names):
>> > engines[name] = rec = {}
>> > rec['engine'] = engine_from_config(
>> > config.get_section(name),
>> > prefix='sqlalchemy.',
>> > poolclass=pool.NullPool)
>> >
>> > Over here I have both forms of multi db at the same time. There's two
>> migration environments, and one migration environment does two databases
>> that are largely mirrored, so three databases total. All three make use
>> of a common env.py script that's in my application as a library, they then
>> implement an env.py in the migration environment that draws upon the
>> myapp/lib/env.py script for common features.
>> >
>> > You can pass instructions to a single env.py that may be controlling
>> multiple databases using --tag:
>> >
>> > "alembic --tag my_tag"
>> >
>> > "my_tag" is available in env.py as context.get_tag_argument(). You
>> can use that to conditionally run migrations on one database or the other.
>> >
>> > This is all DIY. Multi-database migrations can happen in many
>> different ways so you'd need to build the approach that suits your
>> situation best.
>> >
>> >
>>
>> thank you very much.
>>
>>
>> --
>> I like python!
>> UliPad <<The Python Editor>>: http://code.google.com/p/ulipad/
>> UliWeb <<simple web framework>>: http://code.google.com/p/uliweb/
>> My Blog: http://hi.baidu.com/limodou
>>
>
--
SQLAlchemy -
The Python SQL Toolkit and Object Relational Mapper
http://www.sqlalchemy.org/
To post example code, please provide an MCVE: Minimal, Complete, and Verifiable
Example. See http://stackoverflow.com/help/mcve for a full description.
---
You received this message because you are subscribed to the Google Groups
"sqlalchemy" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to sqlalchemy+unsubscr...@googlegroups.com.
To view this discussion on the web visit
https://groups.google.com/d/msgid/sqlalchemy/e7177036-152b-4a34-a052-bec6a176aed4n%40googlegroups.com.
