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70 lines
2.1 KiB
ReStructuredText
70 lines
2.1 KiB
ReStructuredText
7 years ago
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Altering the database
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=====================
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Alter the model code
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--------------------
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First alter the model code. Simply edit ``models.py`` and modify all required model classes.
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Make sure that your changes reflect on related classes as the migration should be consistent from one structure to another.
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Do not commit your changes at that stage.
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Generate the migration script
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-----------------------------
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After you modify the database models, you need to generate a new schema
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migration script:
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.. code-block:: bash
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python manage.py db migrate
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This will generate a new script in ``migrations/versions`` that you must review
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before adding it for commit.
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Because we use SQLite, make sure that you use batch operation for column changes and deletion. For instance:
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.. code-block:: python
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def downgrade():
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with op.batch_alter_table('fetch') as batch:
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batch.drop_column('last_check')
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batch.drop_column('error')
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or
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.. code-block:: python
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def upgrade():
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# spam_threshold is a X/15 based value, we're converting it to percent.
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for user in User.query.all():
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user.spam_threshold = int(100. * float(user.spam_threshold or 0.) / 15.)
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db.session.commit()
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# set default to 80%
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with op.batch_alter_table('user') as batch:
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batch.alter_column('spam_threshold', default=80.)
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Remove unneeded Alembic comments and add a proper description to your migration script.
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Upgrade your local database
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---------------------------
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At that point, to start working on the changed database structure, you will need to upgrade your local database. Make a backup of your database, then:
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.. code-block:: bash
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python manage.py db upgrade
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If any error arises, restore the backup, fix the migration script and try again.
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Actually work on your feature or fix
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------------------------------------
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If your changes to the database are related to a view or template, you may not work on these to reflect the changes and access the proper columns/tables.
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Commit your work
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----------------
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You may finally commit your work as a whole: database changes and view/template changes. Do not forget to add the migration script.
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