flask框架 資料庫

綜合案例-圖書管理系統

from flask import flask, render_template, flash, redirect

from wtforms import stringfield, submitfield
from flask_wtf import flaskform
from flask_sqlalchemy import sqlalchemy
from wtforms.validators import datarequired
class book(db.model):
id = db.column(db.integer, primary_key=true)
name = db.column(db.string(64))
author_id = db.column(db.integer, db.foreignkey("author.id"))
class author(db.model):
id = db.column(db.integer, primary_key=true)
name = db.column(db.string(64))
books = db.relationship("book", backref="author")
class bookform(flaskform):
book_name = stringfield(label='書籍名:', validators=[datarequired('書籍名不能為空')])
author_name = stringfield(label='作者名:', validators=[datarequired('作者名不能為空')])
submit = submitfield('新增')
def index():
book_from = bookform()
author = author.query.all()
return render_template("book_show.html", book_from=book_from, author=author)
def add_book():
book_form = bookform()
book_name = book_form.book_name.data
author_name = book_form.author_name.data
author = author.query.filter(author.name == author_name).first()
if author:
if not book.query.filter(book.name == book_name,book.author_id == author.id).first():
book = book()
book.name = book_name
book.author_id = author.id
db.session.add(book)
db.session.commit()
flash('新增書籍成功')
else:
flash('新增失敗，該書籍已存在')
else:
author = author()
author.name = author_name
db.session.add(author)
db.session.commit()
book = book()
book.name = book_name
book.author_id = author.id
db.session.add(book)
db.session.commit()
flash('新增作者和書籍成功')
return redirect('/')
if __name__ == "__main__":
# db.drop_all()
db.create_all()
# au1 = author()
# au1.name = '老王'
# au2 = author()
# au2.name = '老李'
# au3 = author()
# au3.name = '老六'
# db.session.add_all([au1, au2, au3])
# db.session.commit()
# book1 = book()
# book1.name = '從前有座山'
# book1.author_id = au1.id
# book2 = book()
# book2.name = '葫蘆娃'
# book2.author_id = au2.id
# book3 = book()
# book3.name = '小金剛'
# book3.author_id = au3.id
# db.session.add_all([book1, book2, book3])
# db.session.commit()

from flask import flask

from flask_script import manager
from flask_sqlalchemy import sqlalchemy
from flask_migrate import migrate, migratecommand
#使用命令python xx.py db init初始化遷移資料夾 python xx.py db migrate -m '注釋'生成遷移指令碼 python xx.py db upgrade/downgrade 公升級資料庫/降級資料庫 
manager.add_command('db', migratecommand)
class student(db.model):
id = db.column(db.integer, primary_key=true)
name = db.column(db.string(64))
age = db.column(db.integer)
def __init__(self, name):
self.name = name
def index():
return "helloworld"
if __name__ == "__main__":
# db.drop_all()
db.create_all()
stu1 = student('zs')
stu2 = student('ls')
stu3 = student('ww')
db.session.add_all([stu1, stu2, stu3])
db.session.commit()
manager.run()

一對多

class book(db.model):

id = db.column(db.integer, primary_key=true)
name = db.column(db.string(64))
author_id = db.column(db.integer, db.foreignkey("author.id"))
class author(db.model):
id = db.column(db.integer, primary_key=true)
name = db.column(db.string(64))
books = db.relationship("book", backref="author")

student_course = db.table(

"student_course",
db.column("student_id", db.integer, db.foreignkey("student.id")),
db.column("course_id", db.integer, db.foreignkey("course.id"))
)class student(db.model):
id = db.column(db.integer, primary_key=true)
name = db.column(db.string(64))
courses = db.relationship("course", secondary=student_course, backref="student", lazy="dynamic")
def __init__(self, name):
self.name = name
class course(db.model):
id = db.column(db.integer, primary_key=true)
name = db.column(db.string(64))
def __init__(self, name):
self.name = name

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