Re: [sqlalchemy] Does alembic support multiple databases?
There are a few possibilities. You could have separate configuration files
for each database (eg. alembic-dev.ini and alembic-prod.ini), and choose
between them with the "--config" command line option.
If you want to stick to a single configuration file, you could put both
connection strings in your config file with different prefixes. For example:
sqlalchemy.dev.url = driver://user:pass@localhost/dbname
sqlalchemy.prod.url = driver://user:pass@localhost/dbname
Then, in your env.py file, locate the lines that say:
connectable = engine_from_config(
config.get_section(config.config_ini_section),
prefix="sqlalchemy.",
poolclass=pool.NullPool,
)
...and change it to use either "sqlalchemy.dev." or "sqlalchemy.prod." as
the prefix based on some condition. For example, you could use
"context.get_x_argument" and pass the environment name on the command line:
https://alembic.sqlalchemy.org/en/latest/api/runtime.html#alembic.runtime.environment.EnvironmentContext.get_x_argument
Hope that helps,
Simon
On Mon, May 9, 2022 at 8:57 PM thavha tsiwana
wrote:
> 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
>>> wrote:
>>> >
>>> > On Apr 29, 2012, at 10:56 AM, limodou wrote:
>>> >
>>> >> On Sun, Apr 29, 2012 at 10:42 PM, Michael Bayer
>>> >> 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"
>>> >
>>> >
Re: [sqlalchemy] Does alembic support multiple databases?
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
>> wrote:
>> >
>> > On Apr 29, 2012, at 10:56 AM, limodou wrote:
>> >
>> >> On Sun, Apr 29, 2012 at 10:42 PM, Michael Bayer
>> >> 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 <>: http://code.google.com/p/ulipad/
>> UliWeb <>: 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.
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Re: [sqlalchemy] Does alembic support multiple databases?
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
> wrote:
> >
> > On Apr 29, 2012, at 10:56 AM, limodou wrote:
> >
> >> On Sun, Apr 29, 2012 at 10:42 PM, Michael Bayer
> >> 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 <>: http://code.google.com/p/ulipad/
> UliWeb <>: 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.
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Re: [sqlalchemy] Does alembic support multiple databases?
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. On Apr 29, 2012, at 7:45 AM, limodou wrote: I can't find how to enable alembic support multiple databases. -- 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 -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com. To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en. -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com. To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
Re: [sqlalchemy] Does alembic support multiple databases?
On Sun, Apr 29, 2012 at 10:42 PM, Michael Bayer mike...@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? -- 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 -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com. To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
Re: [sqlalchemy] Does alembic support multiple databases?
On Sun, Apr 29, 2012 at 10:56 PM, limodou limo...@gmail.com wrote: On Sun, Apr 29, 2012 at 10:42 PM, Michael Bayer mike...@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? BTW, I manage different databases in different directory now. -- 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 -- You received this message because you are subscribed to the Google Groups sqlalchemy group. To post to this group, send email to sqlalchemy@googlegroups.com. To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
Re: [sqlalchemy] Does alembic support multiple databases?
On Apr 29, 2012, at 10:56 AM, limodou wrote:
On Sun, Apr 29, 2012 at 10:42 PM, Michael Bayer
mike...@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.
--
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Re: [sqlalchemy] Does alembic support multiple databases?
On Sun, Apr 29, 2012 at 11:13 PM, Michael Bayer
mike...@zzzcomputing.com wrote:
On Apr 29, 2012, at 10:56 AM, limodou wrote:
On Sun, Apr 29, 2012 at 10:42 PM, Michael Bayer
mike...@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
--
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