SQLAlchemy and Alembic

DB migrations using Alembic
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# 1. install alembic - time of writing current version used - alembic 1.7.5 
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pip install alembic
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# 2. Inititiate alembic
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alembic init alembic
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# 3. Update alemnic.ini file with db connection details, for example:
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sqlalchemy.url = mysql+pymysql://root:[email protected]:3306/service_dashboard
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# 4. Edit alembic/env.py and add the following:
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from models import Base
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target_metadata = Base.metadata
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# save your file
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#5. For existing db generate first migration and add your stuff, so create migration manually, by running:
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alembic revision -m "First migration"
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# 6. After above commend yuo will have a new versioned fiele in versions directory, for example: bf35c09ac2e3
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# edit file and add your changes, for example we want to add new columns:
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def upgrade():
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    op.add_column('test_table', sa.Column('column_name', sa.String(255)))
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def downgrade():
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    op.drop_column('test_table', 'column_name')
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# 7. Run migrations with command: 
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alembic upgrade head
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# For future you will generate new migrations with automatic migrations:
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alembic revision --autogenerate -m "Add new columns"
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