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

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。

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

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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