Interfacing with Multiple Temporary Tables in Django

When working with MySQL databases containing temporary tables that share a similar schema but have dynamically assigned names, it becomes necessary to establish an interface between these tables and Django. This article explores the feasibility of utilizing a single Django model to retrieve data from multiple tables with dynamic names.

Creating a Dynamic Model Factory

To dynamically generate model classes based on database table names, a factory function can be created. The factory function, 'getModel', takes the table name as an argument and returns a model class with a dynamic 'db_table' attribute. For example:

def getModel(db_table):
    class MyClass(models.Model):
        # Define model fields here
        class Meta:
            db_table = db_table
    
    return MyClass

Metaclass Approach for Dynamic Class Names

The 'Meta' class attribute in Django is typically a shared instance across all instantiations of a particular model class. However, by defining a custom metaclass, we can change the class name at runtime. This allows us to create a new class for each dynamic table name.

class MyClassMetaclass(models.base.ModelBase):
    def __new__(cls, name, bases, attrs):
        name  = db_table
        return models.base.ModelBase.__new__(cls, name, bases, attrs)

class MyClass(models.Model):
    __metaclass__ = MyClassMetaclass

    class Meta:
        db_table = db_table

Dynamic Modification of 'db_table' Attribute

Alternatively, you can modify the 'db_table' attribute dynamically even after the model class has been defined:

MyModel._meta.db_table = '10293847_table'

By utilizing these techniques, Django can be used to interface with multiple temporary tables, enabling the retrieval of data from dynamically named tables.