模块化peewee

Question

假设我有几个简单的模型居住在food.py中

import peewee as pw

db = pw.SqliteDatabase('food.db')

class BaseModel(pw.Model):
    class Meta:
        database = db

class Taco(BaseModel):
    has_cheese = pw.BooleanField()

class Spaghetti(BaseModel):
    has_meatballs = pw.BooleanField()

db.connect()

# populate with some data if table doesn't exist
from random import random
if not Taco.table_exists():
    db.create_table(Taco)
    for _ in range(10):
        Taco.create( has_cheese = (random() < 0.5) )
    db.commit()
if not Spaghetti.table_exists():
    db.create_table(Spaghetti)
    for _ in range(10):
        Spaghetti.create( has_meatballs = (random() < 0.5) )
    db.commit()

之后，我有food.py和food.db。但是假设Taco和Spaghetti模型变得越来越庞大和复杂，所以我想将它们分成不同的文件。具体来说，我想用典型的层次结构在我的food中创建一个PYTHONPATH文件夹：

food/
    - __init__.py
    - BaseModel.py
    - Taco.py
    - Spaghetti.py
    - db/
        - food.db

我想将模型放入各自的.py文件中，并有一个类似于以下内容的__init__.py文件：

import peewee as pw

db = pw.SqliteDatabase('./db/food.db')

from . import BaseModel
from . import Taco
from . import Spaghetti

db.connect()

但是，这显然不起作用，因为BaseModel.py无法访问db。如果可以以这种方式模块化多个peewee模型，那么正确的方法是什么？

Answer 1

显然，诀窍是连接到BaseModel.py文件中的数据库。我将给出一个完整的模块内容概述。假设顶层文件夹名为food，并驻留在PYTHONPATH中。最后，假设food.db存在于food/db/food.db中并已被填充(例如，在问题中的第一个代码块的底部)。

以下是模块文件：

__init__.py

from Taco import Taco
from Spaghetti import Spaghetti

BaseModel.py

import peewee as pw
db = pw.SqliteDatabase('/abs/path/to/food/db/food.db')

class BaseModel(pw.Model):
    class Meta:
        database = db

Taco.py

import peewee as pw
from BaseModel import BaseModel

class Taco(BaseModel):
    has_cheese = pw.BooleanField()

Spaghetti.py

import peewee as pw
from BaseModel import BaseModel

class Spaghetti(BaseModel):
    has_meatballs = pw.BooleanField()

例如，现在您可以编写一个脚本(当然，驻留在模块文件夹之外)，例如：

main.py

import food

for t in food.Taco.select():
    print "Taco", t.id, ("has" if t.has_cheese else "doesn't have"), "cheese"

生产：

Taco 1 has cheese
Taco 2 has cheese
Taco 3 has cheese
Taco 4 doesn't have cheese
Taco 5 doesn't have cheese
Taco 6 has cheese
Taco 7 has cheese
Taco 8 has cheese
Taco 9 doesn't have cheese
Taco 10 doesn't have cheese

Answer 2

你在道路上遇到了一个问题：

__location__ = os.path.realpath(os.path.join(os.getcwd(), os.path.dirname(__file__)))
db = pw.SqliteDatabase(os.path.join(__location__, 'db/food.db'));

还尝试实现类的__init__，并将db作为参数传递给它：

class BaseModel(pw.Model):
    def __init__(self, db = None)
        self.database = db

比在__init__.py

from BaseModel import BaseModel
db = pw.SqliteDatabase('./db/food.db')
bm = BaseModel(db)

Answer 3

有关使用peewee模块化烧瓶应用程序的说明，请参阅本文：

http://charlesleifer.com/blog/structuring-flask-apps-a-how-to-for-those-coming-from-django/