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I'm trying to use flask, sqlalchemy, and flask_migrate...

But every time run manage.py migrate, alembic always detect my model as a new table.

I think that i put table_args in my model to store table in a different postgres schema:

class Entry(db.Model):
    __table_args__ = {'schema': app.config['BASE_SCH']}
    id = db.Column(db.Integer, primary_key=True)
    title = db.Column(db.String(100))
    slug = db.Column(db.String(100), unique=True)
    body = db.Column(db.Text)
    status = db.Column(db.SmallInteger, default=STATUS_PUBLIC)
    created_timestamp = db.Column(db.DateTime, default=datetime.datetime.now)
    modified_timestamp = db.Column(db.DateTime, default=datetime.datetime.now, onupdate=datetime.datetime.now)

If I to delete the table_args line of my model, the flask migrate works properly. Storing my table in puclic postgres schema.

So, how can I use different postgres table schemas with flask?

Thanks!

Rômulo Moraes
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  • Did you check the generated migration script? I assume it is missing the `schema`, maybe if you add it manually things will work for you. – Miguel Grinberg Nov 14 '16 at 05:00
  • Hi @Miguel, thank you for your comment... In the migration script there is a schema definition in the end of each create table block. I suspect that perhaps the alembic not be able to recognize during migration different table schemes (postgres). – Rômulo Moraes Nov 14 '16 at 12:52
  • I have the exact same issue - have a model that is not in the default schema, initial migration looks good (has the schema specified) and running it does create the table in the correct schema. But the next call to `flask db migrate` creates a new migration that's an exact duplicate of the first one, like Alembic is not seeing that the table already exists in the DB. – Jules Olléon Nov 30 '17 at 04:18

1 Answers1

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Finally figured this out: there is an include_schemas option in configure that you have to set to True to force Alembic to scan all schemas before generating the migration.

(Slightly) more details: http://alembic.zzzcomputing.com/en/latest/api/runtime.html#alembic.runtime.environment.EnvironmentContext.configure.params.include_schemas

It's not completely clear to me why Alembic/Flask-Migrate was generating the migrations for tables in non default schemas without this option set in the first place... or rather, the fact that it would create migrations for non default schemas but not discover these tables in the DB is a surprising behavior.

Jules Olléon
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