Django 自动增量字段

Question

我试图对某个字段进行自动增量，但不知道正确的方法。我正在使用 postgres 来管理我的数据库：我尝试了 Autofield 数据类型，但它不起作用。我猜 django 正在使用默认的 id 字段，我想用我的 WO_ID 字段替换它。

models.py

class Workorder(models.Model): 
    WO_ID = models.BigIntegerField(blank=True, primary_key=True)
    WO_DateDefWO = models.DateField(default=datetime.now)
    WO_DateSched = models.DateField(blank=True, null=True)
    WO_DateFinished = models.DateField(blank=True, null=True)
    WO_ST_ID_Sign = models.BigIntegerField(blank=True, null=True)
    WO_Status_ID = models.BigIntegerField(blank=True, null=True, default=1, choices=STATUS_CHOICES)
    WO_Type_ID = models.BigIntegerField(blank=True, null=True, default=1, choices=TYPE_CHOICES)
    WO_Comments = models.CharField(max_length=254, blank=True, null=True)
    WO_Nav_ID = models.BigIntegerField(blank=True, null=True)
    WO_Nav_Kons_ID = models.CharField(max_length=12, blank=True, null=True)
    WO_Nav_Name = models.CharField(max_length=254, blank=True, null=True)
    WO_Nav_CustAdr = models.CharField(max_length=254, blank=True, null=True)
    WO_Nav_Debt = models.FloatField(blank=True, null=True)
    WO_Nav_PropCode = models.CharField(max_length=254, blank=True, null=True)
    WO_Nav_DepCode = models.CharField(max_length=254, blank=True, null=True)
    WO_Nav_PhoneNo = models.CharField(max_length=254, blank=True, null=True)
    WO_Nav_ReasonCompl = models.CharField(max_length=254, blank=True, null=True)
    WO_NightShift = models.BooleanField(default=False)
    WO_Priority = models.BigIntegerField(blank=True, null=True)
    WO_RE_ID = models.BigIntegerField(blank=True, null=True)
    WO_MapUrl = models.CharField(max_length=254, blank=True, null=True)

    def __unicode__(self):
        return self.WO_ID

views.py

from django.shortcuts import render, get_object_or_404, redirect
from django import forms
from django.views.generic import TemplateView
from django.core.serializers import serialize
from django.http import HttpResponse
from MMS.models import Workorder
from MMS import forms
from MMS.forms import CreateWorkorder
from django.contrib.auth.forms import UserCreationForm, AuthenticationForm
from . import forms


def workorders_list(request):
    workorders_all = Workorder.objects.all().values_list('WO_ID', flat=True)
    return render(request, "workorders_list.html")

def home_page(request):
    return render(request, "home_page.html")

def workorder_create(request):
    if request.method == "POST":
        form = CreateWorkorder(request.POST)
        if form.is_valid():
            CreateWorkorder_item = form.save(commit=False)
            CreateWorkorder_item.save()
            return redirect('/workorder/' + str(CreateWorkorder_item.WO_ID) + '/')
    else:
        form = CreateWorkorder()
    return render(request, 'workorders/workorder_create.html', {'form': form})


def workorder_edit(request, id=None):
    item = get_object_or_404(Workorder, WO_ID=id)
    form = CreateWorkorder(request.POST or None, instance=item)
    if form.is_valid():
        form.save()
        return redirect('/workorder/' + str(item.WO_ID) + '/')
    return render(request, 'workorders/workorder_edit.html', {'form': form})


def workorder(request, id):
    workorder = Workorder.objects.get(WO_ID=id)
    return render(request, 'workorders/workorder.html', {'workorder': workorder})

postgresql 自动增量代码：

CREATE SEQUENCE public.MMS_workorder_id_seq
    INCREMENT 1
    START 1
alter table MMS_workorder ALTER COLUMN "WO_ID" SET DEFAULT nextval('MMS_workorder_id_seq');

Answer 1

默认情况下，Django 为每个模型提供名为 id 的自动增量字段。见https://docs.djangoproject.com/en/2.1/topics/db/models/#automatic-primary-key-fields

如果你想创建一个额外的自增字段，你可以使用AutoFieldhttps://docs.djangoproject.com/en/2.1/ref/models/fields/#django.db.models.AutoField

创建自定义 id 字段

class MyModel(models.Model):
    wo_id = models.AutoField(primary_key=True)

这会跳过默认 id 字段的创建并创建名称为 wo_id 的自动增量主字段。