Sequence-safe postgres backend for Django

This is a replacement for the default postgres backend for Django, version 1.7 and newer.

The difference is it discovers sequence names differently, by inspecting the metadata table information_schema.columns instead of using the function pg_get_serial_sequence(). The former shows which sequence is currently in use by a column, while the latter shows which table owns a sequence.

In the common case these two lead to the same sequence, but it is perfectly possible to have one sequence be used by two diffferent tables (and owned by only one of them). Furthermore, if a table inherits a column with a sequence, then pg_get_serial_sequence() won't find anything for the child table.

Install with pip, and use it in your settings-file:

DATABASES = {
    'default': {
        'ENGINE': 'dpb.postgres_sequencesafe',
        # other settings
    }
}