django动态创建表和动态选择实体

开发有时需要动态创建表，创建完成后需要动态选择model对应的表，该需求如何实现

1、model层   TestBlock为了动态创建表、getBlockModel为了动态选择表

from django.db import models

# Create your models here.
class TestBlock(models.Model):
    BLOCK_ID = models.CharField(max_length=40,primary_key=True, verbose_name='对象ID')
    BLOCK_NAME = models.CharField(max_length=200, verbose_name='姓名')
    class Meta:
        db_table = 'TEST_BLOCK_T'
        indexes = [
        models.Index(fields=['BLOCK_ID'], name='BLOCK_ID _INDEX'),
        models.Index(fields=['BLOCK_NAME'], name='BLOCK_NAME _INDEX'),
        ]



def getBlockModel(table_name):
    class MyCLass(models.Model):
        BLOCK_ID = models.CharField(max_length=40, primary_key=True, verbose_name='对象ID')
        BLOCK_NAME = models.CharField(max_length=200, verbose_name='姓名')
        class Meta:
            db_table = table_name
    return MyCLass

2、url

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from django.urls import path     from . import views   urlpatterns = [       path('autoCreate', views.createTest),       path('autoSelect', views.selectTest), ]

 3、view层createTest方法  重点的地方 注意红色地方，注释掉可以动态创建表，但是如果不注释掉，动态变更实体对应的数据表在使用它，就会报错

ERROR：django.db.utils.OperationalError: (1054, "Unknown column 'TEST_BLOCK_T_1.BLOCK_ID' in 'where clause'")

分别注释 #-------------1-begin-------------------------- 和 # -------------2-begin--------------------------之间的代码，执行代码动态创建两个表并把数据插入进去。

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from django.shortcuts import render   # Create your views here. from .models import * from django.http import HttpResponse from django.db import connection   from django.db.backends.base.schema import BaseDatabaseSchemaEditor     def createTest(request):     #-------------1-begin--------------------------     TestBlock._meta.db_table = 'TEST_BLOCK_T_' + '1'     # #创建分表     cursor = connection.cursor()     editor = BaseDatabaseSchemaEditor(connection)     with BaseDatabaseSchemaEditor(connection) as editor:         editor.create_model(model=TestBlock)     # testBlock = TestBlock()     # testBlock.BLOCK_ID = '1'     # testBlock.BLOCK_NAME = 'oracle'     # testBlock.save()     # -------------1-end--------------------------       # -------------2-begin--------------------------     TestBlock._meta.db_table = 'TEST_BLOCK_T_' + '2'     # #创建分表     cursor = connection.cursor()     editor = BaseDatabaseSchemaEditor(connection)     with BaseDatabaseSchemaEditor(connection) as editor:         editor.create_model(model=TestBlock)       # testBlock1 = TestBlock()     # testBlock1.BLOCK_ID = '2'     # testBlock1.BLOCK_NAME = 'mysql'     # testBlock1.save()     # -------------2-end--------------------------     return HttpResponse("yc is a good man")

 4、view层selectTest方法  动态选择实体对应的表

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def selectTest(request):     TestBlock = getBlockModel('TEST_BLOCK_T_' + '1')     testBlocks = TestBlock.objects.all()     for testBlock in testBlocks:         print('1---testBlock.BLOCK_ID:'+testBlock.BLOCK_ID)         print('1---testBlock.BLOCK_NAME:'+testBlock.BLOCK_NAME)       TestBlock = getBlockModel('TEST_BLOCK_T_' + '2')     testBlocks = TestBlock.objects.all()     for testBlock in testBlocks:         print('2---testBlock.BLOCK_ID:'+testBlock.BLOCK_ID)         print('2---testBlock.BLOCK_NAME:'+testBlock.BLOCK_NAME)     return HttpResponse("yc is a good man")

 数据结果：

1---testBlock.BLOCK_ID:1
1---testBlock.BLOCK_NAME:oracle
2---testBlock.BLOCK_ID:2
2---testBlock.BLOCK_NAME:mysql

结论是 TestBlock._meta.db_table = 'TEST_BLOCK_T_' + '1'可以动态创建表，而动态选择表只能用TestBlock = getBlockModel('TEST_BLOCK_T_' + '1') 这样的方式。

 

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