Flask-SQLAlchemy how to delete all rows in a single table

问题

How do I delete all rows in a single table using Flask-SQLAlchemy?

Looking for something like this:

>>> users = models.User.query.all()
>>> models.db.session.delete(users)

# but it errs out: UnmappedInstanceError: Class '__builtin__.list' is not mapped

回答1:

Try delete:

models.User.query.delete()

From the docs: Returns the number of rows deleted, excluding any cascades.

回答2:

DazWorrall's answer is spot on. Here's a variation that might be useful if your code is structured differently than the OP's:

num_rows_deleted = db.session.query(Model).delete()

Also, don't forget that the deletion won't take effect until you commit, as in this snippet:

try:
    num_rows_deleted = db.session.query(Model).delete()
    db.session.commit()
except:
    db.session.rollback()

回答3:

Flask-Sqlalchemy

#for all records
db.session.query(Model).delete()
db.session.commit()

here DB is the object Flask-SQLAlchemy class. It will delete all records from it and if you want to delete specific records then try filter clause in the query. ex.

#for specific value
db.session.query(Model).filter(Model.id==123).delete()
db.session.commit()

来源：https://stackoverflow.com/questions/16573802/flask-sqlalchemy-how-to-delete-all-rows-in-a-single-table