49 lines
1.5 KiB
ReStructuredText
49 lines
1.5 KiB
ReStructuredText
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Upgrade a database
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==================
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Database schema migration are handled in two ways:
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* New tables
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For this we simply rely on the ``createdb`` script used when creating the
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database the first time.
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* Changes to existing tables
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For changes to existing tables, we rely on `Alembic <http://alembic.readthedocs.org/>`_.
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This allows us to do upgrade and downgrade of schema migration, kind of like
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one would do commits in a system like git.
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To upgrade the database to the latest version simply run:
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::
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alembic upgrade head
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This may fail for different reasons:
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* The change was already made in the database
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This can be because the version of the database schema saved is incorrect.
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It can be debugged using the following commands:
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* Find the current revision: ``alembic current``
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* See the entire history: ``alembic history``
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Once the revision at which your database should be is found (in the history)
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you can declare that your database is at this given revision using:
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``alembic stamp <revision id>``.
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Eventually, if you do not know where your database is or should be, you can
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do an iterative process stamping the database for every revision, one by one
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trying everytime to ``alembic upgrade`` until it works.
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* The database used does not support some of the changes
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SQLite is handy for development but does not support all the features of a
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real database server. Upgrading a SQLite database might therefore not work,
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depending on the changes done.
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In some cases, if you are using a SQLite database, you will have to destroy
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it and create a new one.
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