Bộ đề thi thực tế môn Ebook2LateX

Bài 7: models.py cốt lõi

Học để hiểu bảng, khóa ngoại, relationship, cascade và JSONB.

import uuid
from sqlalchemy import Column, String, Integer, ForeignKey, DateTime, Boolean, Text, Numeric
from sqlalchemy.dialects.postgresql import UUID, JSONB
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import relationship
from sqlalchemy.sql import func

Base = declarative_base()

class User(Base):
    __tablename__ = "users"
    user_id = Column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
    username_email = Column(String(255), unique=True, nullable=False)
    password_hash = Column(Text, nullable=False)
    role = Column(String(20), default="Editor")
    documents = relationship("Document", back_populates="owner")

class Document(Base):
    __tablename__ = "documents"
    id = Column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
    user_id = Column(UUID(as_uuid=True), ForeignKey("users.user_id", ondelete="SET NULL"))
    file_name = Column(Text, nullable=False)
    file_path_url = Column(Text, nullable=False)
    status = Column(String(50), default="Pending")
    owner = relationship("User", back_populates="documents")
    formulas = relationship("FormulaEntry", back_populates="document", cascade="all, delete-orphan")

class FormulaEntry(Base):
    __tablename__ = "formula_entries"
    id = Column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
    document_id = Column(UUID(as_uuid=True), ForeignKey("documents.id", ondelete="CASCADE"), nullable=False)
    latex_content = Column(Text)
    order_index = Column(Integer, nullable=False)
    document = relationship("Document", back_populates="formulas")

Bài 8: database.py và seed.py

Học để mở Session, thêm dữ liệu, commit, rollback và đóng kết nối.

# app/database.py
import os
from dotenv import load_dotenv
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker, declarative_base

load_dotenv()
SQLALCHEMY_DATABASE_URL = os.getenv("DATABASE_URL")
engine = create_engine(SQLALCHEMY_DATABASE_URL)
SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
Base = declarative_base()

# seed.py
import uuid
from app.database import SessionLocal
from app.models import User, Document, FormulaEntry

def seed_data():
    db = SessionLocal()
    try:
        test_user = User(user_id=uuid.uuid4(), username_email="teo@dalat.edu.vn",
                         password_hash="hashed_password_here", role="Admin")
        db.add(test_user)
        db.flush()

        test_doc = Document(id=uuid.uuid4(), user_id=test_user.user_id,
                            file_name="Giao_trinh_Toan_12.pdf",
                            file_path_url="/uploads/toan12.pdf", status="Completed")
        db.add(test_doc)
        db.flush()

        formula = FormulaEntry(id=uuid.uuid4(), document_id=test_doc.id,
                               latex_content=r"\frac{-b \pm \sqrt{b^2 - 4ac}}{2a}",
                               order_index=1)
        db.add(formula)
        db.commit()
    except Exception:
        db.rollback()
        raise
    finally:
        db.close()