[Asterisk-Dev] Re: PostgreSQL support in Asterisk 1.2?

[Tilghman Lesher]

On Wednesday 10 August 2005 12:02, Andrew Kohlsmith wrote:
> On Wednesday 10 August 2005 12:21, Tilghman Lesher wrote:
> > In that case, SQLite cannot be considered to be a DB under your
> > definition, either.  From the documentation [0]:
> >
> > "...SQLite support[s] the concept of "type affinity" on columns.
> > The type affinity of a column is the recommended type for data
> > stored in that column. The key here is that the type is
> > recommended, not required. Any column can still store any type of
> > data..."
> >
> > So much for data consistency checking.
>
> Yeah really, I did not realize that...  Is MySQL so forward about the
> artistic license it takes with my constraints?  Further, I am pretty
> damn sure that SQLite isn't trying to come across as ACID-compliant.

On the contrary, the VERY FIRST feature that SQLite touts is ACID
compliance (http://www.sqlite.org/):

	SQLite is a small C library that implements a self-contained,
	embeddable, zero-configuration SQL database engine. Features include: 

	* Transactions are atomic, consistent, isolated, and durable (ACID)
	even after system crashes and power failures.

> And while I realize I'm stretching for reasons to like SQLite now I
> do want to make note that most systems that would implement SQLite
> are using it strictly for a lite SQL layer in which to work --
> especially since SQLite has no network layer at this time.  Having
> the 'C' in ACID isn't nearly as important if you're the only app
> capable of accessing the DB (crazily contrived examples of file
> locking and such preemptively excluded).

On the contrary, the fact that the files can be accessed concurrently by
multiple processes (and multiple threads!) makes consistency absolutely
essential.  A process-based database has the luxury of knowing that only
it will be accessing its data files at any point in time.

-- 
Tilghman