November 2024
Intermediate to advanced
208 pages
4h 56m
French
Content preview from L'alchimie essentielle de SQLA, 2e édition
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Chapitre 13. Contrôler Alembic
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Dans le chapitre précédent, nous avons appris à créer et à appliquer des migrations, et dans ce chapitre, nous allons voir comment contrôler davantage Alembic. Nous verrons comment connaître le niveau de migration actuel de la base de données, comment rétrograder à partir d'une migration et comment marquer la base de données à un certain niveau de migration.
Déterminer le niveau de migration d'une base de données
Avant que n'effectue des migrations, tu dois vérifier à nouveau quelles migrations ont été appliquées à la base de données. Tu peux déterminer quelle est la dernière migration appliquée à la base de données en utilisant la commande alembic current. Elle te renverra l'ID de révision de la migration en cours et te dira s'il s'agit de la dernière migration (également connue sous le nom de " head "). Exécutons la commande alembic current dans le dossier CH12/ du code d'exemple de ce livre :
# alembic currentINFO[alembic.runtime.migration]ContextimplSQLiteImpl.INFO[alembic.runtime.migration]Willassumenon-transactionalDDL.2e6a6cc63e9(head)
La dernière migration appliquée à la base de données
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