<s>
SQLite	B-Language
(	O
,	O
)	O
is	O
a	O
database	B-General_Concept
engine	I-General_Concept
written	O
in	O
the	O
C	B-Language
programming	I-Language
language	I-Language
.	O
</s>
<s>
It	O
is	O
not	O
a	O
standalone	O
app	O
;	O
rather	O
,	O
it	O
is	O
a	O
library	B-Library
that	O
software	B-Application
developers	I-Application
embed	O
in	O
their	O
apps	B-Application
.	O
</s>
<s>
As	O
such	O
,	O
it	O
belongs	O
to	O
the	O
family	O
of	O
embedded	B-Application
databases	I-Application
.	O
</s>
<s>
It	O
is	O
the	O
most	O
widely	O
deployed	O
database	B-General_Concept
engine	I-General_Concept
,	O
as	O
it	O
is	O
used	O
by	O
several	O
of	O
the	O
top	O
web	B-Application
browsers	I-Application
,	O
operating	B-General_Concept
systems	I-General_Concept
,	O
mobile	O
phones	O
,	O
and	O
other	O
embedded	B-Architecture
systems	I-Architecture
.	O
</s>
<s>
Many	O
programming	O
languages	O
have	O
bindings	B-Application
to	O
the	O
SQLite	B-Language
library	B-Library
.	O
</s>
<s>
It	O
generally	O
follows	O
PostgreSQL	B-Application
syntax	O
,	O
but	O
does	O
not	O
enforce	O
type	O
checking	O
by	O
default	O
.	O
</s>
<s>
This	O
means	O
that	O
one	O
can	O
,	O
for	O
example	O
,	O
insert	O
a	O
string	O
into	O
a	O
column	B-Application
defined	O
as	O
an	O
integer	O
.	O
</s>
<s>
D	O
.	O
Richard	O
Hipp	O
designed	O
SQLite	B-Language
in	O
the	O
spring	O
of	O
2000	O
while	O
working	O
for	O
General	O
Dynamics	O
on	O
contract	O
with	O
the	O
United	O
States	O
Navy	O
.	O
</s>
<s>
Hipp	O
was	O
designing	O
software	O
used	O
for	O
a	O
damage-control	O
system	O
aboard	O
guided-missile	O
destroyers	O
,	O
which	O
originally	O
used	O
HP-UX	B-Application
with	O
an	O
IBM	B-Application
Informix	I-Application
database	O
back-end	O
.	O
</s>
<s>
SQLite	B-Language
began	O
as	O
a	O
Tcl	B-Operating_System
extension	O
.	O
</s>
<s>
In	O
August	O
2000	O
,	O
version	O
1.0	O
of	O
SQLite	B-Language
was	O
released	O
,	O
with	O
storage	O
based	O
on	O
gdbm	B-General_Concept
(	O
GNU	O
Database	O
Manager	O
)	O
.	O
</s>
<s>
In	O
September	O
2001	O
,	O
SQLite	B-Language
2.0	O
replaced	O
gdbm	B-General_Concept
with	O
a	O
custom	O
B-tree	B-Architecture
implementation	O
,	O
adding	O
transaction	B-General_Concept
capability	O
.	O
</s>
<s>
In	O
June	O
2004	O
,	O
SQLite	B-Language
3.0	O
added	O
internationalization	B-General_Concept
,	O
manifest	B-Language
typing	I-Language
,	O
and	O
other	O
major	O
improvements	O
,	O
partially	O
funded	O
by	O
America	O
Online	O
.	O
</s>
<s>
In	O
2011	O
,	O
Hipp	O
announced	O
his	O
plans	O
to	O
add	O
a	O
NoSQL	B-General_Concept
interface	O
to	O
SQLite	B-Language
,	O
as	O
well	O
as	O
announcing	O
UnQL	O
,	O
a	O
functional	O
superset	O
of	O
SQL	B-Language
designed	O
for	O
document-oriented	B-General_Concept
databases	I-General_Concept
.	O
</s>
<s>
In	O
2018	O
,	O
SQLite	B-Language
adopted	O
a	O
Code	O
of	O
Conduct	O
based	O
on	O
the	O
Rule	O
of	O
Saint	O
Benedict	O
which	O
caused	O
some	O
controversy	O
and	O
was	O
later	O
renamed	O
as	O
a	O
Code	O
of	O
Ethics	O
.	O
</s>
<s>
SQLite	B-Language
is	O
one	O
of	O
four	O
formats	O
recommended	O
for	O
long-term	O
storage	O
of	O
datasets	B-General_Concept
approved	O
for	O
use	O
by	O
the	O
Library	B-Library
of	O
Congress	O
.	O
</s>
<s>
SQLite	B-Language
was	O
designed	O
to	O
allow	O
the	O
program	O
to	O
be	O
operated	O
without	O
installing	O
a	O
database	O
management	O
system	O
or	O
requiring	O
a	O
database	B-General_Concept
administrator	I-General_Concept
.	O
</s>
<s>
Unlike	O
client	B-Operating_System
–	I-Operating_System
server	I-Operating_System
database	O
management	O
systems	O
,	O
the	O
SQLite	B-Language
engine	O
has	O
no	O
standalone	O
processes	O
with	O
which	O
the	O
application	B-Application
program	I-Application
communicates	O
.	O
</s>
<s>
Instead	O
,	O
a	O
linker	B-Application
integrates	O
the	O
SQLite	B-Language
library	B-Library
statically	B-Library
or	O
dynamically	B-Application
into	O
an	O
application	B-Application
program	I-Application
which	O
uses	O
SQLite	B-Language
's	O
functionality	O
through	O
simple	O
function	O
calls	O
,	O
reducing	O
latency	O
in	O
database	O
operations	O
;	O
for	O
simple	O
queries	O
with	O
little	O
concurrency	B-Operating_System
,	O
SQLite	B-Language
performance	O
profits	O
from	O
avoiding	O
the	O
overhead	O
of	O
inter-process	B-Operating_System
communication	I-Operating_System
.	O
</s>
<s>
Due	O
to	O
the	O
serverless	O
design	O
,	O
SQLite	B-Language
applications	O
require	O
less	O
configuration	O
than	O
client	B-Operating_System
–	I-Operating_System
server	I-Operating_System
databases	O
.	O
</s>
<s>
SQLite	B-Language
is	O
called	O
zero-conf	O
because	O
it	O
does	O
not	O
require	O
service	O
management	O
(	O
such	O
as	O
startup	O
scripts	O
)	O
or	O
access	O
control	O
based	O
on	O
GRANT	B-Application
and	O
passwords	O
.	O
</s>
<s>
Access	O
control	O
is	O
handled	O
by	O
means	O
of	O
file-system	B-Application
permissions	O
given	O
to	O
the	O
database	O
file	O
itself	O
.	O
</s>
<s>
Databases	O
in	O
client	B-Operating_System
–	I-Operating_System
server	I-Operating_System
systems	O
use	O
file-system	B-Application
permissions	O
that	O
give	O
access	O
to	O
the	O
database	O
files	O
only	O
to	O
the	O
daemon	B-Operating_System
process	I-Operating_System
,	O
which	O
handles	O
its	O
locks	O
internally	O
,	O
allowing	O
concurrent	B-Operating_System
writes	O
from	O
several	O
processes	O
.	O
</s>
<s>
SQLite	B-Language
stores	O
the	O
whole	O
database	O
(	O
definitions	O
,	O
tables	B-Application
,	O
indices	O
,	O
and	O
the	O
data	O
itself	O
)	O
as	O
a	O
single	O
cross-platform	B-Operating_System
file	O
on	O
a	O
host	O
machine	O
,	O
allowing	O
several	O
processes	O
or	O
threads	B-Operating_System
to	O
access	O
the	O
same	O
database	O
concurrently	O
.	O
</s>
<s>
It	O
implements	O
this	O
simple	O
design	O
by	O
locking	B-Operating_System
the	O
database	O
file	O
during	O
writing	O
.	O
</s>
<s>
Write	O
access	O
may	O
fail	O
with	O
an	O
error	B-Application
code	I-Application
,	O
or	O
it	O
can	O
be	O
retried	O
until	O
a	O
configurable	O
timeout	O
expires	O
.	O
</s>
<s>
SQLite	B-Language
read	O
operations	O
can	O
be	O
multitasked	B-Operating_System
,	O
though	O
due	O
to	O
the	O
serverless	O
design	O
,	O
writes	O
can	O
only	O
be	O
performed	O
sequentially	O
.	O
</s>
<s>
This	O
concurrent	B-Operating_System
access	O
restriction	O
does	O
not	O
apply	O
to	O
temporary	O
tables	B-Application
,	O
and	O
it	O
is	O
relaxed	O
in	O
version	O
3.7	O
as	O
write-ahead	B-Algorithm
logging	I-Algorithm
(	O
WAL	O
)	O
enables	O
concurrent	B-Operating_System
reads	O
and	O
writes	O
.	O
</s>
<s>
Since	O
SQLite	B-Language
has	O
to	O
rely	O
on	O
file-system	B-Application
locks	O
,	O
it	O
is	O
not	O
the	O
preferred	O
choice	O
for	O
write-intensive	O
deployments	O
.	O
</s>
<s>
SQLite	B-Language
uses	O
PostgreSQL	B-Application
as	O
a	O
reference	O
platform	O
.	O
</s>
<s>
"	O
What	O
would	O
PostgreSQL	B-Application
do	O
"	O
is	O
used	O
to	O
make	O
sense	O
of	O
the	O
SQL	B-Language
standard	O
.	O
</s>
<s>
One	O
major	O
deviation	O
is	O
that	O
,	O
with	O
the	O
exception	O
of	O
primary	B-Application
keys	I-Application
,	O
SQLite	B-Language
does	O
not	O
enforce	O
type	O
checking	O
;	O
the	O
type	O
of	O
a	O
value	O
is	O
dynamic	O
and	O
not	O
strictly	O
constrained	O
by	O
the	O
schema	B-Application
(	O
although	O
the	O
schema	B-Application
will	O
trigger	O
a	O
conversion	O
when	O
storing	O
,	O
if	O
such	O
a	O
conversion	O
is	O
potentially	O
reversible	O
)	O
.	O
</s>
<s>
SQLite	B-Language
strives	O
to	O
follow	O
Postel	O
's	O
rule	O
.	O
</s>
<s>
SQLite	B-Language
implements	O
most	O
of	O
the	O
SQL-92	B-Language
standard	O
for	O
SQL	B-Language
,	O
but	O
lacks	O
some	O
features	O
.	O
</s>
<s>
For	O
example	O
,	O
it	O
only	O
partially	O
provides	O
triggers	B-Language
and	O
cannot	O
write	O
to	O
views	B-Language
(	O
however	O
,	O
it	O
provides	O
INSTEAD	O
OF	O
triggers	B-Language
that	O
provide	O
this	O
functionality	O
)	O
.	O
</s>
<s>
SQLite	B-Language
uses	O
an	O
unusual	O
type	O
system	O
for	O
a	O
SQL-compatible	O
DBMS	B-General_Concept
:	O
instead	O
of	O
assigning	O
a	O
type	O
to	O
a	O
column	B-Application
as	O
in	O
most	O
SQL	B-Language
database	I-Language
systems	O
,	O
types	O
are	O
assigned	O
to	O
individual	O
values	O
;	O
in	O
language	O
terms	O
it	O
is	O
dynamically	B-Application
typed	O
.	O
</s>
<s>
Moreover	O
,	O
it	O
is	O
weakly	O
typed	O
in	O
some	O
of	O
the	O
same	O
ways	O
that	O
Perl	B-Language
is	O
:	O
one	O
can	O
insert	O
a	O
string	O
into	O
an	O
integer	O
column	B-Application
(	O
although	O
SQLite	B-Language
will	O
try	O
to	O
convert	O
the	O
string	O
to	O
an	O
integer	O
first	O
,	O
if	O
the	O
column	B-Application
's	O
preferred	O
type	O
is	O
integer	O
)	O
.	O
</s>
<s>
This	O
adds	O
flexibility	O
to	O
columns	O
,	O
especially	O
when	O
bound	O
to	O
a	O
dynamically	B-Application
typed	O
scripting	O
language	O
.	O
</s>
<s>
However	O
,	O
the	O
technique	O
is	O
not	O
portable	O
to	O
other	O
SQL	B-Language
products	O
.	O
</s>
<s>
A	O
common	O
criticism	O
is	O
that	O
SQLite	B-Language
's	O
type	O
system	O
lacks	O
the	O
data	O
integrity	O
mechanism	O
provided	O
by	O
statically	B-Library
typed	O
columns	O
,	O
although	O
it	O
can	O
be	O
emulated	O
with	O
constraints	O
like	O
CHECK(typeof(x )	O
=	O
'	O
integer	O
 '	O
)	O
.	O
</s>
<s>
Strict	O
tables	B-Application
were	O
added	O
in	O
version	O
3.37.1	O
.	O
</s>
<s>
Tables	B-Application
normally	O
include	O
a	O
hidden	O
rowid	B-General_Concept
index	O
column	B-Application
,	O
which	O
gives	O
faster	O
access	O
.	O
</s>
<s>
If	O
a	O
database	O
includes	O
an	O
Integer	O
Primary	B-Application
Key	I-Application
column	B-Application
,	O
SQLite	B-Language
will	O
typically	O
optimize	O
it	O
by	O
treating	O
it	O
as	O
an	O
alias	O
for	O
rowid	B-General_Concept
,	O
causing	O
the	O
contents	O
to	O
be	O
stored	O
as	O
a	O
strictly	O
typed	O
64-bit	O
signed	O
integer	O
and	O
changing	O
its	O
behavior	O
to	O
be	O
somewhat	O
like	O
an	O
auto-incrementing	O
column	B-Application
.	O
</s>
<s>
Future	O
versions	O
of	O
SQLite	B-Language
may	O
include	O
a	O
command	O
to	O
introspect	O
whether	O
a	O
column	B-Application
has	O
behavior	O
like	O
that	O
of	O
rowid	B-General_Concept
to	O
differentiate	O
these	O
columns	O
from	O
weakly	O
typed	O
,	O
non-autoincrementing	O
Integer	O
Primary	B-Application
Keys	I-Application
.	O
</s>
<s>
Stored	B-General_Concept
procedures	I-General_Concept
are	O
not	O
supported	O
;	O
this	O
is	O
an	O
explicit	O
choice	O
by	O
the	O
developers	B-Application
to	O
favor	O
simplicity	O
,	O
as	O
the	O
typical	O
use	O
case	O
of	O
SQLite	B-Language
is	O
to	O
be	O
embedded	B-Application
inside	O
a	O
host	O
application	O
that	O
can	O
define	O
its	O
own	O
procedures	O
around	O
the	O
database	O
.	O
</s>
<s>
SQLite	B-Language
version	O
3.7.4	O
first	O
saw	O
the	O
addition	O
of	O
the	O
FTS4	O
(	O
full-text	B-Application
search	I-Application
)	O
module	O
,	O
which	O
features	O
enhancements	O
over	O
the	O
older	O
FTS3	O
module	O
.	O
</s>
<s>
FTS4	O
allows	O
users	O
to	O
perform	O
full-text	B-Application
searches	I-Application
on	O
documents	O
similar	O
to	O
how	O
search	B-Application
engines	I-Application
search	O
webpages	O
.	O
</s>
<s>
Version	O
3.8.2	O
added	O
support	O
for	O
creating	O
tables	B-Application
without	O
rowid	B-General_Concept
,	O
which	O
may	O
provide	O
space	O
and	O
performance	O
improvements	O
.	O
</s>
<s>
Common	O
table	O
expressions	O
support	O
was	O
added	O
to	O
SQLite	B-Language
in	O
version	O
3.8.3	O
.	O
</s>
<s>
In	O
2015	O
,	O
with	O
the	O
json1	O
extension	O
and	O
new	O
subtype	O
interfaces	O
,	O
SQLite	B-Language
version	O
3.9	O
introduced	O
JSON	B-General_Concept
content	O
managing	O
.	O
</s>
<s>
SQLite	B-Language
's	O
code	O
is	O
hosted	O
with	O
Fossil	B-Protocol
,	O
a	O
distributed	B-Protocol
version	I-Protocol
control	I-Protocol
system	I-Protocol
that	O
uses	O
SQLite	B-Language
as	O
a	O
local	O
cache	O
for	O
its	O
non-relational	B-General_Concept
database	I-General_Concept
format	O
,	O
and	O
SQLite	B-Language
's	O
SQL	B-Language
as	O
an	O
implementation	O
language	O
.	O
</s>
<s>
A	O
standalone	O
command-line	B-Device
shell	B-Operating_System
program	O
called	O
sqlite3	B-Language
is	O
provided	O
in	O
SQLite	B-Language
's	O
distribution	O
.	O
</s>
<s>
It	O
can	O
be	O
used	O
to	O
create	O
a	O
database	O
,	O
define	O
tables	B-Application
,	O
insert	O
and	O
change	O
rows	O
,	O
run	O
queries	O
and	O
manage	O
an	O
SQLite	B-Language
database	O
file	O
.	O
</s>
<s>
It	O
also	O
serves	O
as	O
an	O
example	O
for	O
writing	O
applications	O
that	O
use	O
the	O
SQLite	B-Language
library	B-Library
.	O
</s>
<s>
SQLite	B-Language
uses	O
automated	O
regression	O
testing	O
prior	O
to	O
each	O
release	O
.	O
</s>
<s>
Starting	O
with	O
the	O
August	O
10	O
,	O
2009	O
release	O
of	O
SQLite	B-Language
3.6.17	O
,	O
SQLite	B-Language
releases	O
have	O
100%	O
branch	O
test	O
coverage	O
,	O
one	O
of	O
the	O
components	O
of	O
code	B-Application
coverage	I-Application
.	O
</s>
<s>
The	O
tests	O
and	O
test	O
harnesses	O
are	O
partially	O
public-domain	O
and	O
partially	O
proprietary	B-Application
.	O
</s>
<s>
SQLite	B-Language
is	O
included	O
by	O
default	O
in	O
:	O
</s>
<s>
FreeBSD	B-Operating_System
where	O
starting	O
with	O
10-RELEASE	O
version	O
in	O
January	O
2014	O
,	O
it	O
is	O
used	O
by	O
the	O
core	O
package	O
management	O
system	O
.	O
</s>
<s>
Solaris	B-Application
10	I-Application
where	O
the	O
Service	B-Operating_System
Management	I-Operating_System
Facility	I-Operating_System
database	O
is	O
serialized	O
for	O
booting	O
.	O
</s>
<s>
ADO.NET	B-Device
adapter	O
,	O
initially	O
developed	O
by	O
Robert	O
Simpson	O
,	O
is	O
maintained	O
jointly	O
with	O
the	O
SQLite	B-Language
developers	B-Application
since	O
April	O
2010	O
.	O
</s>
<s>
ODBC	B-Application
driver	O
has	O
been	O
developed	O
and	O
is	O
maintained	O
separately	O
by	O
Christian	O
Werner	O
.	O
</s>
<s>
Werner	O
's	O
ODBC	B-Application
driver	O
is	O
the	O
recommended	O
connection	O
method	O
for	O
accessing	O
SQLite	B-Language
from	O
OpenOffice.org	B-Application
.	O
</s>
<s>
COM	B-Application
(	O
ActiveX	B-Application
)	O
wrapper	O
making	O
SQLite	B-Language
accessible	O
on	O
Windows	O
to	O
scripted	O
languages	O
such	O
as	O
JScript	B-Language
and	O
VBScript	B-Application
.	O
</s>
<s>
This	O
adds	O
SQLite	B-Language
database	O
capabilities	O
to	O
HTML	B-Application
Applications	I-Application
(	O
HTA	B-Application
)	O
.	O
</s>
<s>
The	O
browsers	B-Application
Google	B-Application
Chrome	I-Application
,	O
Opera	B-Application
,	O
Safari	B-Application
and	O
the	O
Android	B-Application
Browser	B-Application
all	O
allow	O
for	O
storing	O
information	O
in	O
,	O
and	O
retrieving	O
it	O
from	O
,	O
a	O
SQLite	B-Language
database	O
within	O
the	O
browser	B-Application
,	O
using	O
the	O
Web	O
SQL	B-Language
Database	I-Language
technology	O
,	O
although	O
this	O
is	O
rapidly	O
becoming	O
deprecated	O
(	O
namely	O
superseded	O
by	O
IndexedDB	O
)	O
.	O
</s>
<s>
Internally	O
,	O
these	O
Chromium	B-Language
based	O
browsers	B-Application
use	O
SQLite	B-Language
databases	O
for	O
storing	O
configuration	O
data	O
like	O
site	O
visit	O
history	O
,	O
cookies	O
,	O
download	O
history	O
etc	O
.	O
</s>
<s>
Mozilla	B-Application
Firefox	I-Application
and	O
Mozilla	B-Application
Thunderbird	I-Application
store	O
a	O
variety	O
of	O
configuration	O
data	O
(	O
bookmarks	O
,	O
cookies	O
,	O
contacts	O
etc	O
.	O
)	O
</s>
<s>
in	O
internally	O
managed	O
SQLite	B-Language
databases	O
.	O
</s>
<s>
Until	O
Firefox	B-Application
version	O
57	O
(	O
"	O
Firefox	B-Application
Quantum	O
"	O
)	O
,	O
there	O
was	O
a	O
third-party	O
add-on	O
that	O
used	O
the	O
API	O
supporting	O
this	O
functionality	O
to	O
provide	O
a	O
user	O
interface	O
for	O
managing	O
arbitrary	O
SQLite	B-Language
databases	O
.	O
</s>
<s>
Several	O
third-party	O
add-ons	O
can	O
make	O
use	O
of	O
JavaScript	O
APIs	O
to	O
manage	O
SQLite	B-Language
databases	O
.	O
</s>
<s>
Adobe	O
Systems	O
uses	O
SQLite	B-Language
as	O
its	O
file	O
format	O
in	O
Adobe	B-Operating_System
Photoshop	I-Operating_System
Lightroom	I-Operating_System
,	O
a	O
standard	O
database	O
in	O
Adobe	B-Operating_System
AIR	I-Operating_System
,	O
and	O
internally	O
within	O
Adobe	B-Application
Reader	I-Application
.	O
</s>
<s>
As	O
with	O
much	O
Apple	O
software	O
,	O
Photos	B-Application
uses	O
SQLite	B-Language
internally	O
.	O
</s>
<s>
Audacity	B-Language
uses	O
SQLite	B-Language
as	O
its	O
file	O
format	O
,	O
as	O
of	O
version	O
3.0.0	O
.	O
</s>
<s>
Evernote	B-Application
uses	O
SQLite	B-Language
to	O
store	O
its	O
local	O
database	O
repository	O
in	O
Windows	O
.	O
</s>
