Django - DatabaseError：没有这样的表

问题描述

我定义了两个模型：

  class Server（models.Model）：
 owner = models.ManyToManyField 'Person'）
 
 class Person（models.Model）：
 name = models.CharField（max_length = 50）
 
 admin.site.register 
 admin.site.register（Person）
  

之后，我甚至检查了sql，just为乐趣：

  BEGIN; 
 CREATE TABLEservers_server_owners（
idinteger NOT NULL PRIMARY KEY，
server_idinteger NOT NULL，
person_idinteger NOT NULL，
 UNIQUE （server_id，person_id）
）
; 
 CREATE TABLEservers_server（
idinteger NOT NULL PRIMARY KEY，
namevarchar（50）NOT NULL，
portinteger unsigned NOT NULL，
stateinteger NOT NULL 
）
; 
 CREATE TABLEservers_person（
idinteger NOT NULL PRIMARY KEY，
namevarchar（50）NOT NULL 
）
; 
 COMMIT; 
  

还有 CREATE TABLEservers_server_owners

我运行 syncdb 将新模型安装到数据库。我去管理界面定义一些对象，但我得到以下错误：

  DatabaseError at / admin / servers / server / 1 / 
没有这样的表：servers_server_owners 
  

服务器，再次运行 syncdb 启动服务器：仍然有同样的问题。为什么不能找到，表，即使它只是告诉我它创建了id？

解决方案

该表从未创建。因为我是django相当新的，我不知道 ./ manage.py syncdb 不更新现有模型，而是只创建不存在的模型。

因为模型'Server'在我添加其他模型之前就存在，并且它已经在db中，'syncdb'实际上没有创建新表。 p>

I defined two models:

class Server(models.Model):
    owners = models.ManyToManyField('Person')

class Person(models.Model):
    name = models.CharField(max_length=50)

admin.site.register(Server)
admin.site.register(Person)

After that I even checked the sql, just for fun:

BEGIN;
CREATE TABLE "servers_server_owners" (
    "id" integer NOT NULL PRIMARY KEY,
    "server_id" integer NOT NULL,
    "person_id" integer NOT NULL,
    UNIQUE ("server_id", "person_id")
)
;
CREATE TABLE "servers_server" (
    "id" integer NOT NULL PRIMARY KEY,
    "name" varchar(50) NOT NULL,
    "port" integer unsigned NOT NULL,
    "state" integer NOT NULL
)
;
CREATE TABLE "servers_person" (
    "id" integer NOT NULL PRIMARY KEY,
    "name" varchar(50) NOT NULL
)
;
COMMIT;

There it even says CREATE TABLE "servers_server_owners"

I ran syncdb to install the new models to the database. I went to the admin-interface to define some objects to play with, but I got the following error:

DatabaseError at /admin/servers/server/1/
no such table: servers_server_owners

I shutdown the dev-server, ran syncdb again, started the server: Still same problem. Why can't it find, the table, even though it just told me it created id?

解决方案

Actually the problem was that the table never got created. Since I am fairly new with django, I did not know that ./manage.py syncdb does not update existing models, but only creates the ones that do not exist.

Because the model 'Server' existed before I added the other model, and it was already in the db, 'syncdb' did not actually create the new tables.

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