Absolute and relative dating methods

If you generate a pickle using Django version N, there is no guarantee that pickle will be readable with Django version N 1.

This may be desirable if you want to update just one or a few fields on an object.

There will be a slight performance benefit from preventing all of the model fields from being updated in the database. This only deletes the object in the database; the Python instance will still exist and will still have data in its fields.

Historical documents and calendars can be used to find such absolute dates; however, when working in a site without such documents, it is hard for absolute dates to be determined.

As long as there is organic material present, radiocarbon dating is a universal dating technique that can be applied anywhere in the world.

It behaves like a normal attribute on the model, but is actually an alias for whichever attribute is the primary key field for the model.

You can read and set this value, just as you would for any other attribute, and it will update the correct field in the model.For example, Christian time counts the birth of Christ as the beginning, AD 1 (Anno Domini); everything that occurred before Christ is counted backwards from AD as BC (Before Christ).The Greeks consider the first Olympic Games as the beginning or 776 BC.Note that in the case of identical date values, these methods will use the primary key as a tie-breaker.This guarantees that no records are skipped or duplicated.If you assign auto-primary-key values manually, make sure not to use an already-existing primary-key value! Explicitly specifying auto-primary-key values is mostly useful for bulk-saving objects, when you’re confident you won’t have primary-key collision.