NOT NULL constraint failed:

Django创建表格并迁移以后使用django shell创建了一些数据，再通过create函数创建数据时遇到NOT NULL constraint failed:
请帮我看一下吧
这是我的模型

from django.db import models

# Create your models here.
class User(models.Model):
    name = models.CharField(
        max_length=30,
        unique=True
    )
    age = models.IntegerField(
        default=1
    )

这是我的函数

from django.http import HttpResponse
from django.shortcuts import render
from .models import User

# Create your views here.
def get_html(req):
    return render(req, "item.html")
def create_user(req):
    # 解析参数
    params = req.POST
    name = params.get('u_name')
    age = params.get('u_age')
    # id = params.get('u_id')
    user = User.objects.create(
        name=name,
        age=age,
        # id = id
    )
    return HttpResponse("创建成功！")