Extragen

Extract from live database and generate code to populate a new database through SQLAlchemy API.

Goal

Python/SQLAlchemy code generation to populate a test database used for tests setup.

The test database must hold copy of data of actual database, based on the SQLAlchemy mapper definitions.

Use case

The developer writes a SQLAlchemy query.

He can then pass an instance of the result set to the tool.

The result set is designated by its python dotted name.

Query without parameters

db = getDb('sanitel')
Bovine = db.getMapper('BOVINE')
AdultBovine = db.query(Bovine)
AdultBovine = AdultBovine.filter(Bovine.age > 2)
adultBovines = AdultBovine.all()

foundation -r bovines.adultBovines

It outputs a python module in the current directory.

from Bovines import Bovine

def setup(session):
        bovine1 = Bovine()
        bovine1.name = 'Marguerite'
        bovine1.age = 3
        session.save(bovine)
        bovine2 = Bovine()
        bovine2.name = 'Antoinette'
        bovine1.age = 4
        session.save(bovine2)
        session.flush()

class TestAdultBovines(TestCase):
        def setUp(self):
                db = getDb('sanitel')
                setup_adultBovines.setup(db.session)

        def testOlder(self):
                from bovines import adultBovines
                for bovine in adultBovines:
                        self.failIf(bovine.age <= 2)

Query with parameters

db = getDb('sanitel')
Bovine = db.getMapper('BOVINE')
def bovinesOlderThan(age):
        BovineOlderThan = db.query(Bovine)
        BovineOlderThan = AdultBovine.filter(Bovine.age > age)
        return BovineOlderThan.all()

foundation -r bovines.bovinesOlderThan --age=2

TODO

Expand documentation for memoize generator