Solved!

.gitignore

@@ -60,6 +60,7 @@ coverage.xml
 local_settings.py
 db.sqlite3
 db.sqlite3-journal
+library.db
 
 # Flask stuff:
 instance/
@@ -128,3 +129,5 @@ dmypy.json
 # Pyre type checker
 .pyre/
 .idea/
+
+.vscode/

crud.py

@@ -0,0 +1,82 @@
+from sqlalchemy.orm import Session
+import models
+from fastapi import HTTPException
+import schemas
+
+
+def get_book_by_id(book_id: int, db: Session):
+    return db.query(models.Book).filter(models.Book.id == book_id).first()
+
+
+def get_book_by_title(title: str, db: Session):
+    return db.query(models.Book).filter(models.Book.title == title).first()
+
+
+def create_book(author_id: int, book: schemas.BookCreate, db: Session):
+    if not get_author_by_id(author_id, db):
+        raise HTTPException(status_code=404, detail="Author not found")
+    db_book = models.Book(**book.model_dump(), author_id=author_id)
+    db.add(db_book)
+    db.commit()
+    db.refresh(db_book)
+    return db_book
+
+
+def get_author_by_id(author_id: int, db: Session):
+    return db.query(models.Author).filter(models.Author.id == author_id).first()
+
+
+def get_author_by_name(name: str, db: Session):
+    return db.query(models.Author).filter(models.Author.name == name).first()
+
+
+def create_author(author: schemas.AuthorCreate, db: Session):
+    if get_author_by_name(author.name, db):
+        raise HTTPException(
+            status_code=400, detail="Author with this name already exists"
+        )
+    db_author = models.Author(**author.model_dump())
+    db.add(db_author)
+    db.commit()
+    db.refresh(db_author)
+    return db_author
+
+
+def get_all_books(db: Session, skip: int = 0, limit: int = 100):
+    return db.query(models.Book).offset(skip).limit(limit).all()
+
+
+def get_books_by_author(author_id: int, db: Session, skip: int = 0, limit: int = 100):
+    return (
+        db.query(models.Book)
+        .filter(models.Book.author_id == author_id)
+        .offset(skip)
+        .limit(limit)
+        .all()
+    )
+
+
+def get_all_authors(db: Session, skip: int = 0, limit: int = 100):
+    return db.query(models.Author).offset(skip).limit(limit).all()
+
+
+def get_authors_with_books(db: Session):
+    return db.query(models.Author).filter(models.Author.books.any()).all()
+
+
+def delete_book(book_id: int, db: Session):
+    book = get_book_by_id(book_id, db)
+    if not book:
+        raise HTTPException(status_code=404, detail="Book not found")
+    db.delete(book)
+    db.commit()
+    return {"detail": "Book deleted"}
+
+
+def delete_author(author_id: int, db: Session):
+    author = get_author_by_id(author_id, db)
+    if not author:
+        raise HTTPException(status_code=404, detail="Author not found")
+    db.delete(author)
+    db.commit()
+    return {"detail": "Author deleted"}

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:///./library.db"
+
+engine = create_engine(
+    SQLALCHEMY_DATABASE_URL, connect_args={"check_same_thread": False}
+)
+
+SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
+
+Base = declarative_base()

main.py

@@ -0,0 +1,74 @@
+from sqlalchemy.orm import Session
+from fastapi import FastAPI, Depends, HTTPException
+
+from database import SessionLocal, engine
+import models
+import schemas
+import crud
+
+models.Base.metadata.create_all(bind=engine)
+
+app = FastAPI()
+
+
+def get_db():
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()
+
+
+@app.post("/authors", response_model=schemas.AuthorResponse)
+def create_author(author: schemas.AuthorCreate, db: Session = Depends(get_db)):
+    return crud.create_author(author, db)
+
+
+@app.get("/authors", response_model=list[schemas.AuthorResponse])
+def read_authors(skip: int = 0, limit: int = 100, db: Session = Depends(get_db)):
+    return crud.get_all_authors(db, skip=skip, limit=limit)
+
+
+@app.get("/authors/{author_id}", response_model=schemas.AuthorResponse)
+def read_author(author_id: int, db: Session = Depends(get_db)):
+    db_author = crud.get_author_by_id(author_id, db)
+    if db_author is None:
+        raise HTTPException(status_code=404, detail="Author not found")
+    return db_author
+
+
+@app.delete("/authors/{author_id}")
+def delete_author(author_id: int, db: Session = Depends(get_db)):
+    return crud.delete_author(author_id, db)
+
+
+@app.post("/authors/{author_id}/books", response_model=schemas.BookResponse)
+def create_book(
+    book: schemas.BookCreate, author_id: int, db: Session = Depends(get_db)
+):
+    return crud.create_book(author_id, book, db)
+
+
+@app.get("/books", response_model=list[schemas.BookResponse])
+def read_books(
+    db: Session = Depends(get_db),
+    author_id: int | None = None,
+    skip: int = 0,
+    limit: int = 100,
+):
+    if author_id is not None:
+        return crud.get_books_by_author(author_id, db, skip=skip, limit=limit)
+    return crud.get_all_books(db, skip=skip, limit=limit)
+
+
+@app.get("/books/{book_id}", response_model=schemas.BookResponse)
+def read_book(book_id: int, db: Session = Depends(get_db)):
+    db_book = crud.get_book_by_id(book_id, db)
+    if db_book is None:
+        raise HTTPException(status_code=404, detail="Book not found")
+    return db_book
+
+
+@app.delete("/books/{book_id}")
+def delete_book(book_id: int, db: Session = Depends(get_db)):
+    return crud.delete_book(book_id, db)

models.py

@@ -0,0 +1,24 @@
+from sqlalchemy import String, ForeignKey, Date
+from sqlalchemy.orm import relationship, Mapped, mapped_column
+from datetime import date
+from database import Base
+
+
+class Author(Base):
+    __tablename__ = "authors"
+
+    id: Mapped[int] = mapped_column(primary_key=True)
+    name: Mapped[str] = mapped_column(String(255), unique=True)
+    bio: Mapped[str] = mapped_column(String)
+    books: Mapped[list["Book"]] = relationship("Book", back_populates="author")
+
+
+class Book(Base):
+    __tablename__ = "books"
+
+    id: Mapped[int] = mapped_column(primary_key=True)
+    title: Mapped[str] = mapped_column(String(255))
+    summary: Mapped[str] = mapped_column(String)
+    publication_date: Mapped[date] = mapped_column(Date)
+    author_id: Mapped[int] = mapped_column(ForeignKey("authors.id"), index=True)
+    author: Mapped["Author"] = relationship(back_populates="books")

schemas.py

@@ -0,0 +1,35 @@
+from pydantic import BaseModel, ConfigDict
+from datetime import date
+
+
+class BookBase(BaseModel):
+    title: str
+    summary: str
+    publication_date: date
+
+
+class BookCreate(BookBase):
+    pass
+
+
+class BookResponse(BookBase):
+    id: int
+    author_id: int
+
+    model_config = ConfigDict(from_attributes=True)
+
+
+class AuthorBase(BaseModel):
+    name: str
+    bio: str
+
+
+class AuthorCreate(AuthorBase):
+    pass
+
+
+class AuthorResponse(AuthorBase):
+    id: int
+    books: list[BookResponse] = []
+
+    model_config = ConfigDict(from_attributes=True)