On Tue, 7 Mar 2017 15:07:04 +0000, Rahkonen Jukka (MML) wrote:
Hi,
I have a slight feeling that there may be some trouble if attribute
"ROWID" is INTEGER PRIMARY KEY but it does not AUTOINCREMENT and
users
do lot of deletes and inserts. Maybe not if the triggers in r-tree
tables are clever enough. Just a slight feeling but perhaps you
should
test also cases where ROWID differs from OID and __ROWID__?
Hi Jukka,
we can safely exclude any possible dangerous side-effect.
in SQLite any INTEGER PRIMARY KEY definition will always
ensure that an appropriate value will be automatically
set if not explicitly provided.
what exactly does the AUTOINCREMENT keyword is just
slightly changing the mechanism adopted to automatically
assign PK values.
1. not declaring AUTOINCREMENT
SQLite will search for the biggest PK value, and
will adopt this value increased by 1 as the new
PK value.
if the max possible value for an INTEGER 64bit
has already been used (an highly unrealistic
condition) then SQLite will search if there
is some free "hole" in the PK sequence, and
will reuse the first unused value it can find
note: in this exceptional case it's not
exactly true that ROWIDs will be generated
in a regularly ascending order; sometimes
lower values could be possibly returned.
2. declaring AUTOINCREMENT
in this case the automatically generated PK
values can never return back; they can simply
growth until the maximum value supported
by an INTEGER 64bit is reached.
and at this point the auto-sequence will
definitely stop working.
bye Sandro
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