Preparation of the basic database structure (cards and decks)

flashcards/base.py

@@ -0,0 +1,55 @@
+from flashcards.database import session, Card, Deck, init_db
+
+
+def add_deck(name):
+    session.add(Deck(name=name))
+    session.commit()
+
+
+def delete_deck(deck_id):
+    deck = session.query(Deck).filter_by(id=deck_id).first()
+    session.delete(deck)
+    session.commit()
+
+
+def list_decks():
+    decks = session.query(Deck).all()
+
+    if decks:
+        print("Existing decks:")
+        for deck in decks:
+            print(f"{deck.id}: {deck.name}")
+    else:
+        print("There are no decks created yet")
+
+
+def add_card(front, back, deck_id=1):
+    session.add(Card(front=front, back=back, deck_id=deck_id))
+    session.commit()
+
+
+def delete_card(card_id):
+    card = session.query(Card).filter_by(id=card_id).first()
+    session.delete(card)
+    session.commit()
+
+
+def list_cards():
+    cards = session.query(Card).all()
+
+    if cards:
+        print("Existing cards:")
+        for card in cards:
+            print(f"{card.id}: {card.front} - {card.back}")
+    else:
+        print("There are no cards created yet")
+
+
+def main():
+    init_db()
+    list_decks()
+    list_cards()
+
+
+if __name__ == "__main__":
+    main()

flashcards/database.py

@@ -0,0 +1,45 @@
+from sqlalchemy import create_engine, Column, Integer, String, ForeignKey
+from sqlalchemy.orm import sessionmaker, declarative_base, relationship
+
+DATABASE = "data/example.db"
+
+engine = create_engine(f"sqlite:///{DATABASE}")
+Session = sessionmaker(bind=engine)
+session = Session()
+Base = declarative_base()
+
+
+class Deck(Base):
+    __tablename__ = "decks"
+
+    id = Column(Integer, primary_key=True)
+    name = Column(String, nullable=False)
+
+    cards = relationship("Card", order_by="Card.id",
+                         cascade="all, delete-orphan", back_populates="deck")
+
+    def __repr__(self):
+        return f"<Deck(name='{self.name}')>"
+
+
+class Card(Base):
+    __tablename__ = "cards"
+
+    id = Column(Integer, primary_key=True)
+    front = Column(String, nullable=False)
+    back = Column(String, nullable=False)
+    deck_id = Column(Integer, ForeignKey('decks.id'), nullable=False)
+
+    deck = relationship("Deck", back_populates="cards")
+
+    def __repr__(self):
+        return f"<Card(front='{self.front}', back='{self.back}')>"
+
+
+def init_db():
+    Base.metadata.drop_all(engine)
+    Base.metadata.create_all(engine)
+
+    default_deck = Deck(name="default")
+    session.add(default_deck)
+    session.commit()

pyproject.toml

@@ -11,7 +11,8 @@ packages = [
 ]
 
 [tool.poetry.dependencies]
-python = "^3.5"
+python = "^3.6"
+SQLAlchemy = "^1.4.17"
 
 [tool.poetry.dev-dependencies]