46 lines
1.8 KiB
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46 lines
1.8 KiB
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==============================
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Making changes to the database
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==============================
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In order to make a change to the mogan database you must update the database
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models and then create a migration to reflect that change.
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There are two ways to create a migration which are described below, both of
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these generate a new migration file. In this file there is only one function:
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* ``upgrade`` - The function to run when
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``mogan-dbsync upgrade`` is run, and should be populated with
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code to bring the database up to its new state from the state it was in
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after the last migration.
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For further information on creating a migration, refer to
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`Create a Migration Script`_ from the alembic documentation.
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Autogenerate
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------------
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This is the simplest way to create a migration. Alembic will compare the models
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to an up to date database, and then attempt to write a migration based on the
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differences. This should generate correct migrations in most cases however
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there are some cases when it can not detect some changes and may require
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manual modification, see `What does Autogenerate Detect (and what does it not
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detect?)`_ from the alembic documentation.
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::
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mogan-dbsync upgrade
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mogan-dbsync revision -m "A short description" --autogenerate
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Manual
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------
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This will generate an empty migration file, with the correct revision
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information already included. However the upgrade function is left empty
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and must be manually populated in order to perform the correct actions on
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the database::
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mogan-dbsync revision -m "A short description"
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.. _Create a Migration Script: http://alembic.zzzcomputing.com/en/latest/tutorial.html#create-a-migration-script
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.. _What does Autogenerate Detect (and what does it not detect?): http://alembic.zzzcomputing.com/en/latest/autogenerate.html#what-does-autogenerate-detect-and-what-does-it-not-detect
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