如何在django迁移中执行原始SQL [英] How do I execute raw SQL in a django migration

问题描述

我知道Django中的光标对象。在迁移中是否还有其他首选方式来执行原始SQL？我想为我的一个模型表引入postgresql分区。分区逻辑是一组功能和触发器，必须添加到我想要自动化的设置上的数据库中。

解决方案

一种方式：

我发现这样做的最好办法是使用RunSQL：

迁移包含RunSQL类。要执行此操作：

1. ./ manage.py makemigrations --empty myApp / li>
   
2. 编辑创建的迁移文件以包括：

operations =
migrations.RunSQL（'RAW SQL CODE'）
]

另一种方法

我最初解决问题的方法是使用 post_migrate 信号调用游标来执行我的原始SQL。

我必须添加到我的应用程序是这样的：

在 __ init __。py myApp add：

  default_app_config ='myApp.apps.MyAppConfig'
  

创建一个文件 apps.py ：

从django.apps导入AppConfig
从django.db.models.signals导入post_migrate
从myApp.db_partition_triggers导入create_partition_triggers


class MyAppConfig（AppConfig）：
name ='myApp'
verbose_name =我的Ap p

def ready（self）：
post_migrate.connect（create_partition_triggers，sender = self）

新文件 db_partition_triggers.py ：

  from django.db import connection 
 
 
 def create_partition_triggers（** kwargs）：
 print'（re）为myApp创建分区触发器'
 trigger_sql =CREATE OR REPLACE FUNCTION ...;如果不存在（...）CREATE TRIGGER ...
 cursor = connection.cursor（）
 cursor.execute（trigger_sql）
 print'完成创建分区触发器'
  

现在每个 manage.py syncdb 或 manage.py migrate 这个函数被调用，所以确保它使用 CREATE OR REPLACE 和如果不存在，因此可以处理现有的功能。

I am aware of the cursor object in Django. Is there any other preferred way to execute raw SQL in migrations? I want to introduce postgresql partitioning for one of my models tables. The partition logic is a bunch of functions and triggers that have to be added to the database on setup which I'd like to automate.

解决方案

One way:

The best way I found to do this is using RunSQL:

Migrations contains the RunSQL class. To do this:

1. ./manage.py makemigrations --empty myApp
2. edit the created migrations file to include:

operations = [ migrations.RunSQL('RAW SQL CODE') ]

Another way

The way I solved my problem initially was using the post_migrate signal to call a cursor to execute my raw SQL.

What I had to add to my app was this:

in the __init__.py of myApp add:

default_app_config = 'myApp.apps.MyAppConfig'

Create a file apps.py:

from django.apps import AppConfig
from django.db.models.signals import post_migrate
from myApp.db_partition_triggers import create_partition_triggers


class MyAppConfig(AppConfig):
    name = 'myApp'
    verbose_name = "My App"

    def ready(self):
        post_migrate.connect(create_partition_triggers, sender=self)

New file db_partition_triggers.py:

from django.db import connection


def create_partition_triggers(**kwargs):
    print '  (re)creating partition triggers for myApp...'
    trigger_sql = "CREATE OR REPLACE FUNCTION...; IF NOT EXISTS(...) CREATE TRIGGER..."
    cursor = connection.cursor()
    cursor.execute(trigger_sql)
    print '  Done creating partition triggers.'

Now on every manage.py syncdb or manage.py migrate this function is called. So make sure it uses CREATE OR REPLACE and IF NOT EXISTS. So it can handle existing functions.

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