sql_app: basic models and schemas from FastAPI docs

- Classes in models describe tables in database

	- Classes in schemas desribe pydantic models to
	read from the API.

	- database provides a connection and sessions to
	the database.

	- crud exposes the interface to the database, i.e.
	actions we can take from the application onto the
	database

Signed-off-by: HeshamTB <hishaminv@gmail.com>

sql_app/crud.py

@@ -0,0 +1,38 @@
+# CRUD (Create, Read, Update, Delete) from db
+
+from sqlalchemy.orm import Session
+
+from . import models, schemas
+
+
+def get_user(db: Session, user_id: int):
+    return db.query(models.User).filter(models.User.id == user_id).first()
+
+
+def get_user_by_email(db: Session, email: str):
+    return db.query(models.User).filter(models.User.email == email).first()
+
+
+def get_users(db: Session, skip: int = 0, limit: int = 100):
+    return db.query(models.User).offset(skip).limit(limit).all()
+
+
+def create_user(db: Session, user: schemas.UserCreate):
+    fake_hashed_password = user.password + "notreallyhashed"
+    db_user = models.User(email=user.email, hashed_password=fake_hashed_password)
+    db.add(db_user)
+    db.commit()
+    db.refresh(db_user)
+    return db_user
+
+
+def get_iot_entities(db: Session, skip: int = 0, limit: int = 100):
+    return db.query(models.IotEntity).offset(skip).limit(limit).all()
+
+
+def create_iot_entity(db: Session, item: schemas.IotEntityCreate, user_id: int):
+    db_item = models.Item(**item.dict(), owner_id=user_id)
+    db.add(db_item)
+    db.commit()
+    db.refresh(db_item)
+    return db_item

sql_app/database.py

@@ -0,0 +1,14 @@
+from sqlalchemy import create_engine
+from sqlalchemy.ext.declarative import declarative_base
+from sqlalchemy.orm import sessionmaker
+
+SQLALCHEMY_DATABASE_URL = "sqlite:///./sql_app.db"
+# SQLALCHEMY_DATABASE_URL = "postgresql://user:password@postgresserver/db"
+
+# For sqlite
+engine = create_engine(
+    SQLALCHEMY_DATABASE_URL, connect_args={"check_same_thread": False}
+)
+SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
+
+Base = declarative_base()

sql_app/models.py

@@ -0,0 +1,25 @@
+from sqlalchemy import Boolean, Column, ForeignKey, Integer, String
+from sqlalchemy.orm import relationship
+
+from .database import Base
+
+
+class User(Base):
+    __tablename__ = "user_accounts"
+
+    id = Column(Integer, primary_key=True, index=True)
+    email = Column(String, unique=True, index=True)
+    hashed_password = Column(String)
+    is_active = Column(Boolean, default=True)
+
+    items = relationship("Item", back_populates="owner")
+
+
+class IotEntity(Base):
+    __tablename__ = "iot_entities"
+
+    id = Column(Integer, primary_key=True, index=True)
+    description = Column(String, index=True)
+    owner_id = Column(Integer, ForeignKey("users.id"))
+
+    owner = relationship("User", back_populates="items")

sql_app/schemas.py

@@ -0,0 +1,37 @@
+from typing import Optional
+
+from pydantic import BaseModel
+
+
+class IotEntityBase(BaseModel):
+    id: int
+    description: str
+
+
+class IotEntityCreate(IotEntityBase):
+    pass
+
+
+class IotEntity(IotEntityBase):
+    id: int
+    description: str
+
+    class Config:
+        orm_mode = True
+
+
+class UserBase(BaseModel):
+    email: str
+
+
+class UserCreate(UserBase):
+    password: str
+
+
+class User(UserBase):
+    id: int
+    is_active: bool
+    authorized_devices: list[IotEntity] = []
+
+    class Config:
+        orm_mode = True