模块化peewee

Question

假设我有几个简单的模型驻留在 food.py:

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 模型变得越来越大和复杂，所以我想将它们分成不同的文件。具体来说，我想在我的 PYTHONPATH 中创建一个具有典型层次结构的 food 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，并有一个看起来像这样的 __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，这显然行不通，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

你的路径有问题：

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

也尝试实现类的 __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 __init__.py:

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

Answer 2

显然，诀窍是连接到 BaseModel.py 文件中的数据库。我将给出模块内容的完整概述。假设顶级文件夹名为 food 并且位于 PYTHONPATH 中。最后假设 food.db 存在于 food/db/food.db 中并且已经被填充（例如，在问题的第一个代码块的底部）。

模块文件如下：

__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()

现在，例如，您可以编写一个脚本（当然位于模块文件夹之外），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"

产生：

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 3

有关使用 peewee 模块化 Flask 应用程序的说明，请参阅此 post：

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

模块化peewee

Modularizing peewee

python

python-module

peewee