Clear data for all tables via flask-sqlalchemy

app.py

def clear_data(session):
    meta = db.metadata
    for table in reversed(meta.sorted_tables):
        print 'Clear table %s' % table
        session.execute(table.delete())
    session.commit()

@ashutosh-sharma

Truncate.

db.drop_all() == "DROP TABLE xx"
table.delete() == "TUNCTATE TABLE xx"

How to bypass IntegrityError when truncating data?

What is the type for the db object?

It depends. If using flask_sqlalchemy, then it is: <class 'flask_sqlalchemy.SQLAlchemy'>.

Why the order needs to reversed?

sorted_tables returns a list of tables sorted in order of foreign key dependency. reversed ensure that children are deleted before parents to avoid foreign key violation.

How to bypass IntegrityError when truncating data?

I use a small script like below,

https://gist.github.com/premchalmeti/6aa70c12103025645542a481e6f55a07

Explicitly mention the tables having foreign key then concrete classes.

Thank you! Works like a charm for me!

Why not,

    db.drop_all()
    db.create_all()
    db.session.commit()

Why not,

    db.drop_all()
    db.create_all()
    db.session.commit()

It will spend a lot of time if u doing some like that often. For example, u can use author's code in tests, where u need to clear all tables after commits. Imagine u have 30-40 tests. How much time it will spend?

what is the session datatype?

@NailClaros In case you need to call the clear_data function by passing the session_datatype, you can use:

clear_data(db.session)