Dataclass aware ORM with pluggable backends (DynamoDB included).

Install

Install virtual environment and dependencies using make install

$ make install
$ source venv/bin/activate
(venv) $ 

Run

Start the compose stack, which runs local versions of dynamodb and api gateway

(venv) $ docker compose up -d 

Usage

Run the example below using:

(venv) $ export DYNAMODB=http://localhost:8009
(venv) $ python example/widgets.py

Examples

fromdataclassesimportdataclassfromfleximportFlexObject@dataclassclassInventory(FlexObject):
quantity: int=0@classmethod@propertydefsort_key(cls) ->str:
return'quantity'@dataclassclassButton(Inventory):
type: str="square"widget: str=None@dataclassclassWidget(Inventory):
theme: str="default"_buttons= [Button(name="button zero", quantity=5, id="button0")]
@propertydefbuttons(self) -> []:
buttons=self.relation(Button, backref='widget')
returnbuttons@buttons.setterdefbuttons(self, buttons: str) ->None:
forbuttoninbuttons:
button.widget=self.idself._buttons=buttonsdefsave(self):
super(Widget, self).save()
forbuttoninself._buttons:
button.save()
# SCENARIO 1:# Create table, Button, Widget, Add Buton to Widget. Save Widget""" Create tables """Button.create_table(skip_exists=True)
Widget.create_table(skip_exists=True)
""" Create a Button """button1=Button(name="button one", quantity=5, id="button1")
""" Create a Widget """wid1=Widget(name="widget one", quantity=10, id="widget1")
""" Add a button to widget1's existing list of buttons """wid1.buttons+= [button1]
print("WID1", wid1, wid1.buttons)
""" Save widget 1 """wid1.save()
""" Create another widget """wid2=Widget(name="widget two", quantity=15, id="widget2")
wid2.save()
# SCENARIO 2:# Issue SQL to find Widgets""" Execute arbitrary SQL on the Widget table """results=Widget.execute(f"SELECT * FROM \"Widget\" WHERE quantity<? and id=?", [15, 'widget1'])
forresultinresults:
print("RESULT:", result, result.buttons)
# Find widgets using template object""" Find Widget objects using template """results=Widget.find({'id': 'widget1'}, response=True)
print("FIND:", results.response)
forresultinresults.all():
print("RESULT:", result, result.buttons)
# SCENARIO 3:# Delete specific widget by instance""" Delete widget instance using instance method"""print("DELETE widget1", wid1.delete().response)
# SCENARIO 4:# Delete specific widget by template object""" Try to find deleted object """print("FIND2", Widget.find({'id': 'widget1', 'name': 'widget one'}))
# SCENARIO 5:# Create table, Add Inventory Items""" Create tables """Inventory.create_table(skip_exists=True)
""" Create some Inventory objects and save them """inv=Inventory(name="item", quantity=10, id="item1")
inv.save()
inv=Inventory(name="item", quantity=20, id="item2")
inv.save()
""" Delete widget2 using Class.delete(...) print("DELETE widget2", Widget.delete({'id': 'widget2', 'quantity': 15}))results = Widget.execute(f"DELETE FROM \"Widget\" WHERE quantity=? and name='widget one' and id=?", [10, 'widget1'])print(results)"""