Add models for chapter 5

examples/README.md

@@ -2,10 +2,10 @@
 
 在运行示例程序之前，确保你已经把仓库克隆到本地，并完成创建虚拟环境，安装依赖等操作，详见[获取示例程序](https://docs.helloflask.com/installation)。
 
-每一章的示例程序放在 examples 目录下不同的子文件内，以第 1 章示例程序为例，你需要把工作目录切换到 examples/c1 目录内，然后执行 `flask run` 启动程序：
+每一章的示例程序放在 examples 目录下不同的子文件内，以第 1 章示例程序为例，你需要把工作目录切换到 examples/ch1 目录内，然后执行 `flask run` 启动程序：
 
 ```
-cd examples/c1
+cd examples/ch1
 flask run
 ```
 
@@ -20,8 +20,17 @@ pdm run flask run
 通过切换到不同的示例程序目录来运行不同章节的示例程序。比如，下面的命令将会运行第 4 章的示例程序：
 
 ```
-cd examples/c4
+cd examples/ch4
 flask run  # 或 pdm run flask run
 ```
 
-*在书中相应位置会包含运行实例程序的提示。*
+所有示例程序和章节对应关系如下：
+
+- 第 1 章：`ch1`
+- 第 2 章：`ch2`
+- 第 3 章：`ch3`
+- 第 4 章：`ch4`
+- 第 5 章：`ch5`、`notebook`
+- 第 7 章：`longtalk`、`album`
+
+*在书中相应位置会包含运行示例程序的提示。*

examples/ch5/.flaskenv

@@ -0,0 +1 @@
+FLASK_DEBUG=1

examples/ch5/app.py

@@ -0,0 +1,251 @@
+import os
+import sys
+from datetime import datetime
+from pathlib import Path
+from typing import Optional
+
+import click
+from flask import Flask
+from flask_sqlalchemy import SQLAlchemy
+from sqlalchemy import String, Text, MetaData, ForeignKey, Column, event
+from sqlalchemy.orm import DeclarativeBase, Mapped, mapped_column, relationship
+
+SQLITE_PREFIX = 'sqlite:///' if sys.platform.startswith('win') else 'sqlite:////'
+SQLITE_PATH = Path(__file__).resolve().parent / 'data.db'
+
+
+class Base(DeclarativeBase):
+    metadata = MetaData(naming_convention={
+        'ix': 'ix_%(column_0_label)s',
+        'uq': 'uq_%(table_name)s_%(column_0_name)s',
+        'ck': 'ck_%(table_name)s_%(constraint_name)s',
+        'fk': 'fk_%(table_name)s_%(column_0_name)s_%(referred_table_name)s',
+        'pk': 'pk_%(table_name)s'
+    })
+
+
+app = Flask(__name__)
+app.config['SECRET_KEY'] = os.getenv('SECRET_KEY', 'secret string')
+app.config['SQLALCHEMY_DATABASE_URI'] = os.getenv('DATABASE_URL', SQLITE_PREFIX + str(SQLITE_PATH))
+db = SQLAlchemy(app, model_class=Base)
+
+
+# models
+class Note(db.Model):
+    __tablename__ = 'note'
+
+    id: Mapped[int] = mapped_column(primary_key=True)
+    title: Mapped[str] = mapped_column(String(50))
+    body: Mapped[str] = mapped_column(Text)
+    created_at: Mapped[datetime] = mapped_column(default=datetime.now)
+    updated_at: Mapped[Optional[datetime]] = mapped_column(onupdate=datetime.now)
+
+    def __repr__(self):
+        return f'<Note {self.id}: {self.title}>'
+
+
+# one to many / many to one
+class Author(db.Model):
+    __tablename__ = 'author'
+
+    id: Mapped[int] = mapped_column(primary_key=True)
+    name: Mapped[str] = mapped_column(String(20))
+    phone: Mapped[Optional[str]] = mapped_column(String(11))
+
+    articles: Mapped[list['Article']] = relationship(back_populates='author')
+
+    def __repr__(self):
+        return f'<Author {self.id}: {self.name}>'
+
+
+class Article(db.Model):
+    __tablename__ = 'article'
+
+    id: Mapped[int] = mapped_column(primary_key=True)
+    title: Mapped[str] = mapped_column(String(50))
+    body: Mapped[str] = mapped_column(Text)
+    author_id: Mapped[int] = mapped_column(ForeignKey('author.id'))
+
+    author: Mapped['Author']  = relationship(back_populates='articles')
+
+    def __repr__(self):
+        return f'<Article {self.id}: {self.title}>'
+
+
+# one to one
+class Country(db.Model):
+    __tablename__ = 'country'
+
+    id: Mapped[int] = mapped_column(primary_key=True)
+    name: Mapped[str] = mapped_column(String(30), unique=True)
+
+    capital: Mapped['Capital'] = relationship(back_populates='country')
+
+    def __repr__(self):
+        return f'<Country {self.id}: {self.name}>'
+
+
+class Capital(db.Model):
+    __tablename__ = 'capital'
+
+    id: Mapped[int] = mapped_column(primary_key=True)
+    name: Mapped[str] = mapped_column(String(30), unique=True)
+    country_id: Mapped[int] = mapped_column(ForeignKey('country.id'))
+
+    country: Mapped['Country']  = relationship(back_populates='capital')
+
+    def __repr__(self):
+        return f'<Capital {self.id}: {self.name}>'
+
+
+# many to many
+student_teacher = db.Table(
+    'student_teacher',
+    Column('student_id', ForeignKey('student.id'), primary_key=True),
+    Column('teacher_id', ForeignKey('teacher.id'), primary_key=True)
+)
+
+
+class Student(db.Model):
+    __tablename__ = 'student'
+
+    id: Mapped[int] = mapped_column(primary_key=True)
+    name: Mapped[str] = mapped_column(String(70), unique=True)
+    grade: Mapped[str] = mapped_column(String(20))
+
+    teachers: Mapped[list['Teacher']] = relationship(
+        secondary=student_teacher,
+        back_populates='students'
+    )
+
+    def __repr__(self):
+        return f'<Student {self.id}: {self.name}>'
+
+
+class Teacher(db.Model):
+    __tablename__ = 'teacher'
+
+    id: Mapped[int] = mapped_column(primary_key=True)
+    name: Mapped[str] = mapped_column(String(70), unique=True)
+    office: Mapped[str] = mapped_column(String(20))
+
+    students: Mapped[list['Student']] = relationship(
+        secondary=student_teacher,
+        back_populates='teachers'
+    )
+
+    def __repr__(self):
+        return f'<Teacher {self.id}: {self.name}>'
+
+
+# many to many with extra data
+class Collection(db.Model):
+    __tablename__ = 'collection'
+
+    user_id: Mapped[int] = mapped_column(ForeignKey('user.id'), primary_key=True)
+    photo_id: Mapped[int] = mapped_column(ForeignKey('photo.id'), primary_key=True)
+    created_at: Mapped[datetime] = mapped_column(default=datetime.now)
+    note: Mapped[Optional[str]] = mapped_column(Text)
+
+    user: Mapped['User'] = relationship(back_populates='collections', lazy='joined')
+    photo: Mapped['Photo'] = relationship(back_populates='collections', lazy='joined')
+
+    def __repr__(self):
+        return f'<Collection {self.user_id}-{self.photo_id}: {self.user.name}-{self.photo.filename}>'
+
+
+class User(db.Model):
+    __tablename__ = 'user'
+
+    id: Mapped[int] = mapped_column(primary_key=True)
+    name: Mapped[str] = mapped_column(String(50), unique=True)
+
+    collections: Mapped[list['Collection']] = relationship(
+        back_populates='user',
+        cascade='all, delete-orphan'
+    )
+
+    def __repr__(self):
+        return f'<User {self.id}: {self.name}>'
+
+
+class Photo(db.Model):
+    __tablename__ = 'photo'
+
+    id: Mapped[int] = mapped_column(primary_key=True)
+    filename: Mapped[str] = mapped_column(String(255), unique=True)
+
+    collections: Mapped[list['Collection']] = relationship(
+        back_populates='photo',
+        cascade='all, delete-orphan'
+    )
+
+    def __repr__(self):
+        return f'<Photo {self.id}: {self.filename}>'
+
+
+# cascade and event listener
+class Post(db.Model):
+    __tablename__ = 'post'
+
+    id: Mapped[int] = mapped_column(primary_key=True)
+    title: Mapped[Optional[str]] = mapped_column(String(50))
+    body: Mapped[Optional[str]] = mapped_column(Text)
+    edited_count: Mapped[int] = mapped_column(default=0)
+
+    comments: Mapped[list['Comment']] = relationship(
+        back_populates='post',
+        cascade='all, delete-orphan'
+    )
+
+
+class Comment(db.Model):
+    __tablename__ = 'comment'
+
+    id: Mapped[int] = mapped_column(primary_key=True)
+    body: Mapped[Optional[str]] = mapped_column(Text)
+    post_id: Mapped[int] = mapped_column(ForeignKey('post.id'))
+
+    post: Mapped['Post'] = relationship(back_populates='comments')
+
+
+@event.listens_for(Post.body, 'set')
+def increment_edited_count(target, value, oldvalue, initiator):
+    if target.edited_count is not None:
+        target.edited_count += 1
+
+
+# shell context
+@app.shell_context_processor
+def make_shell_context():
+    return dict(
+        db=db,
+        Note=Note,
+        Author=Author,
+        Article=Article,
+        Country=Country,
+        Capital=Capital,
+        Student=Student,
+        Teacher=Teacher,
+        User=User,
+        Photo=Photo,
+        Collection=Collection,
+        Post=Post,
+        Comment=Comment
+    )
+
+
+# commands
+@app.cli.command('init')
+@click.option('--drop-table', is_flag=True, help='Re-create the tables.')
+def init_command(drop_table):
+    """Initialize the application."""
+    if drop_table:
+        click.confirm(
+            'This operation will delete the tables, do you want to continue?',
+            abort=True
+        )
+        db.drop_all()
+        click.echo('Dropped tables.')
+    db.create_all()
+    click.echo('Initialized.')