【主机管理项目】-（models.py(一对多、多对多数据库创建代码)）

# -*- coding: utf-8 -*-
from __future__ import unicode_literals
from django.db import models

class UserType(models.Model):
    caption = models.CharField(max_length=32)

class User(models.Model):
    name = models.CharField(max_length=32)
    age = models.IntegerField()
    user_type = models.ForeignKey('UserType', to_field='id')

class Host(models.Model):
    envid = models.CharField(max_length=32, db_index=True)
    ip = models.GenericIPAddressField(protocol='both', max_length=32, db_index=True)
    port = models.CharField(max_length=32)
    username = models.CharField(max_length=32)
    password = models.CharField(max_length=32)
    item = models.ForeignKey(to='TestItem', to_field='id')

class TestItem(models.Model):
    item = models.CharField(max_length=32)
    versionNum = models.CharField(max_length=32)

class Application(models.Model):
    name = models.CharField(max_length=32)
    r = models.ManyToManyField('Host')

# 方式一：自定义关系表

class Host(models.Model):
    nid = models.AutoField(primary_key=True)
    hostname = models.CharField(max_length=32, db_index=True)
    ip = models.GenericIPAddressField(protocol="ipv4", db_index=True)
    port = models.IntegerField()
    b = models.ForeignKey(to="Business", to_field='id')

# 10
class Application(models.Model):
    name = models.CharField(max_length=32)

# 2

class HostToApp(models.Model):
    hobj = models.ForeignKey(to='Host', to_field='nid')
    aobj = models.ForeignKey(to='Application', to_field='id')

# HostToApp.objects.create(hobj_id=1,aobj_id=2)
# 方式二：自动创建关系表

class Host(models.Model):
    nid = models.AutoField(primary_key=True)
    hostname = models.CharField(max_length=32, db_index=True)
    ip = models.GenericIPAddressField(protocol="ipv4", db_index=True)
    port = models.IntegerField()
    b = models.ForeignKey(to="Business", to_field='id')

# 10
class Application(models.Model):
    name = models.CharField(max_length=32)
    r = models.ManyToManyField("Host")

# 无法直接对第三张表进行操作

obj = Application.objects.get(id=1)
obj.name

# 第三张表操作
obj.r.add(1)
obj.r.add(2)
obj.r.add(2, 3, 4)
obj.r.add(*[1, 2, 3, 4])

obj.r.remove(1)
obj.r.remove(2, 4)
obj.r.remove(*[1, 2, 3])

obj.r.clear()

obj.r.set([3, 5, 7])

# 所有相关的主机对象“列表” QuerySet
obj.r.all()