When you want to save integers to the db, you usually have the choice between 16-, 32- and 64-bit Integers (also 8- and 24-bit for MySQL). If that doesn't fit your needs and you want to use your db-memory more efficient, this field might be handy to you.
Imagine you have 3 numbers, but need only 10 bit to encode each (i.e. from 0 to 1000). Instead of creating 3 smallint-fields (48 bit), you can create one 'ByteSplitterField' which implements 3 'subfields' and automatically encodes them inside a 32 bit integer. You don't have to take care how each 10-bit chunk is encoded into the 32-bit integer, it's all handled by the field (see also field's description).
Additionally, the Field offers opportunity to use decimal_places for each of your subfields. These are 'binary decimal places', meaning the integer-content is automatically divided by 2, 4, 8, etc. when you fetch the value from the field.
You can also specify how values are rounded ('round' parameter) and what happens when you try to save a value out of range ('overflow' parameter)
Not implemented (maybe in the future if I should need it sometime):
* signed values. All values are positive right now!
* real (10-based) decimal places (actually you could probably directly use DecimalFields here)
* further space optimization, i.e. saving into CharField that's length can be chosen byte-wise
- model
- db
- database
- field
- custom
- custom-model-field
- IntegerField
- multibit-field
- model-field
This is an extension of the DecimalField database field that uses my [Currency Object](http://www.djangosnippets.org/snippets/1525/), [Currency Widget](http://www.djangosnippets.org/snippets/1526/), and [Currency Form Field](http://www.djangosnippets.org/snippets/1527/).
I placed my Currency object in the Django\\utils directory, the widget in Django\\froms\\widgets_special.py, and the form field in Django\\forms\\fields_special.py because I integrated this set of currency objects into the Admin app ( [here](http://www.djangosnippets.org/snippets/1529/) ) and it was just easier to have everything within Django.
UPDATE 08-18-2009: Added 'import decimal' and modified to_python slightly.
The rest of the series: [Currency Object](http://www.djangosnippets.org/snippets/1525/), [Currency Widget](http://www.djangosnippets.org/snippets/1526/), [Currency Form Field](http://www.djangosnippets.org/snippets/1527/), [Admin Integration](http://www.djangosnippets.org/snippets/1529/)
- internationalization
- i18n
- database
- currency
- field
- babel
- decimal
Warning: This python script is designed for Django 0.96.
It exports data from models quite like the `dumpdata` command, and throws the
data to the standard output.
It fixes glitches with unicode/ascii characters. It looked like the 0.96
handles very badly unicode characters, unless you specify an argument that is
not available via the command line. The simple usage is:
$ python export_models.py -a <application1> [application2, application3...]
As a plus, it allows you to export only one or several models inside your
application, and not all of them:
$ python export_models.py application1.MyModelStuff application1.MyOtherModel
Of course, you can specify the output format (serializer) with the -f
(--format) option.
$ python export_models.py --format=xml application1.MyModel
- tool
- dump
- serialization
- export
- db
- database