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Database Migrations

Learn how to manage database migrations in Wegent.

Overview​

Wegent uses Alembic for database migrations. Migrations track changes to the database schema over time.

Migration Commands​

Create a Migration​

wegent db migrate -m "Add user table"

Apply Migrations​

wegent db upgrade

Rollback​

wegent db downgrade -1

Check Status​

wegent db status

Writing Migrations​

Auto-generated Migration​

Alembic can auto-generate migrations based on model changes:

wegent db migrate --autogenerate -m "Add email field"

Manual Migration​

Create a manual migration:

"""Add user preferences table

Revision ID: abc123
Create Date: 2024-01-01
"""

from alembic import op
import sqlalchemy as sa

def upgrade():
    op.create_table(
        'user_preferences',
        sa.Column('id', sa.Integer, primary_key=True),
        sa.Column('user_id', sa.Integer, sa.ForeignKey('users.id')),
        sa.Column('theme', sa.String(50)),
        sa.Column('language', sa.String(10))
    )

def downgrade():
    op.drop_table('user_preferences')

Best Practices​

  • Always review auto-generated migrations
  • Test migrations on a copy of production data
  • Keep migrations small and focused
  • Include both upgrade and downgrade functions
  • Never modify existing migrations after they're deployed