Sets the default file format. SQLite
3.3.0 introduced a new file format (4) that understands descending indexes and uses
a more efficient encoding for Boolean values (integer values 0
and 1). All versions of SQLite after 3.3.0 can read and write
both file formats. SQLite versions before 3.3.0 can only
understand the original (1)
format.
As the number of pre-3.3.0 users declines, it is expected that the default version will be changed to the newer file format.