<s>
A	O
flat-file	B-Application
database	I-Application
is	O
a	O
database	O
stored	O
in	O
a	O
file	O
called	O
a	O
flat	B-Application
file	I-Application
.	O
</s>
<s>
A	O
flat	B-Application
file	I-Application
can	O
be	O
a	O
plain	O
text	B-General_Concept
file	I-General_Concept
(	O
e.g.	O
</s>
<s>
csv	O
,	O
txt	B-General_Concept
or	O
tsv	B-Protocol
)	O
,	O
or	O
a	O
binary	O
file	O
.	O
</s>
<s>
The	O
term	O
has	O
generally	O
implied	O
a	O
small	O
database	O
,	O
but	O
very	O
large	O
databases	B-Application
can	O
also	O
be	O
flat	O
.	O
</s>
<s>
Plain	O
text	B-General_Concept
files	I-General_Concept
usually	O
contain	O
one	O
record	O
per	O
line	O
.	O
</s>
<s>
In	O
comma-separated	O
values	O
and	O
delimiter-separated	B-Protocol
values	I-Protocol
files	O
,	O
fields	O
can	O
be	O
separated	O
by	O
delimiters	B-Algorithm
such	O
as	O
comma	O
or	O
tab	B-Protocol
characters	O
.	O
</s>
<s>
In	O
other	O
cases	O
,	O
each	O
field	B-Application
may	O
have	O
a	O
fixed	O
length	O
;	O
short	O
values	O
may	O
be	O
padded	O
with	O
space	O
characters	O
.	O
</s>
<s>
Extra	O
formatting	O
may	O
be	O
needed	O
to	O
avoid	O
delimiter	B-Algorithm
collision	O
.	O
</s>
<s>
Using	O
delimiters	B-Algorithm
incurs	O
some	O
overhead	O
in	O
locating	O
them	O
every	O
time	O
they	O
are	O
processed	O
(	O
unlike	O
fixed-width	O
formatting	O
)	O
,	O
which	O
may	O
have	O
performance	O
implications	O
.	O
</s>
<s>
However	O
,	O
use	O
of	O
character	O
delimiters	B-Algorithm
(	O
especially	O
commas	O
)	O
is	O
also	O
a	O
crude	O
form	O
of	O
data	B-General_Concept
compression	I-General_Concept
which	O
may	O
assist	O
overall	O
performance	O
by	O
reducing	O
data	O
volumes	O
—	O
especially	O
for	O
data	O
transmission	O
purposes	O
.	O
</s>
<s>
Use	O
of	O
character	O
delimiters	B-Algorithm
which	O
include	O
a	O
length	O
component	O
(	O
Declarative	O
notation	O
)	O
is	O
comparatively	O
rare	O
but	O
vastly	O
reduces	O
the	O
overhead	O
associated	O
with	O
locating	O
the	O
extent	O
of	O
each	O
field	B-Application
.	O
</s>
<s>
Examples	O
of	O
flat	B-Application
files	I-Application
include	O
/etc/passwd	B-Protocol
and	O
/etc/group	B-Application
on	O
Unix-like	B-Operating_System
operating	I-Operating_System
systems	I-Operating_System
.	O
</s>
<s>
Another	O
example	O
of	O
a	O
flat	B-Application
file	I-Application
is	O
a	O
name-and-address	O
list	O
with	O
the	O
fields	O
Name	O
,	O
Address	O
,	O
and	O
Phone	O
Number	O
.	O
</s>
<s>
A	O
list	O
of	O
names	O
,	O
addresses	O
,	O
and	O
phone	O
numbers	O
written	O
by	O
hand	O
on	O
a	O
sheet	O
of	O
paper	O
is	O
a	O
flat-file	B-Application
database	I-Application
.	O
</s>
<s>
This	O
can	O
also	O
be	O
done	O
with	O
any	O
typewriter	O
or	O
word	B-General_Concept
processor	I-General_Concept
.	O
</s>
<s>
A	O
spreadsheet	B-Application
or	O
text	B-Application
editor	I-Application
program	O
may	O
be	O
used	O
to	O
implement	O
a	O
flat-file	B-Application
database	I-Application
,	O
which	O
may	O
then	O
be	O
printed	O
or	O
used	O
online	O
for	O
improved	O
search	O
capabilities	O
.	O
</s>
<s>
Herman	O
Hollerith	O
's	O
work	O
for	O
the	O
US	O
Census	O
Bureau	O
first	O
exercised	O
in	O
the	O
1890	O
United	O
States	O
Census	O
,	O
involving	O
data	O
tabulated	O
via	O
hole	O
punches	O
in	O
paper	O
cards	O
,	O
is	O
sometimes	O
considered	O
the	O
first	O
computerized	O
flat-file	B-Application
database	I-Application
,	O
as	O
it	O
included	O
no	O
cards	O
indexing	O
other	O
cards	O
,	O
or	O
otherwise	O
relating	O
the	O
individual	O
cards	O
to	O
one	O
another	O
,	O
save	O
by	O
their	O
group	O
membership	O
.	O
</s>
<s>
In	O
the	O
1980s	O
,	O
configurable	O
flat-file	B-Application
database	I-Application
computer	B-Application
applications	I-Application
were	O
popular	O
on	O
the	O
IBM	B-Device
PC	I-Device
and	O
the	O
Macintosh	B-Device
.	O
</s>
<s>
These	O
programs	O
were	O
designed	O
to	O
make	O
it	O
easy	O
for	O
individuals	O
to	O
design	O
and	O
use	O
their	O
own	O
databases	B-Application
,	O
and	O
were	O
almost	O
on	O
par	O
with	O
word	B-General_Concept
processors	I-General_Concept
and	O
spreadsheets	B-Application
in	O
popularity	O
.	O
</s>
<s>
Examples	O
of	O
flat-file	B-Application
database	I-Application
software	O
include	O
early	O
versions	O
of	O
FileMaker	B-Application
and	O
the	O
shareware	B-License
PC-File	B-Application
and	O
the	O
popular	O
dBase	B-Application
.	O
</s>
<s>
Flat-file	B-Application
databases	I-Application
are	O
common	O
and	O
ubiquitous	O
because	O
they	O
are	O
easy	O
to	O
write	O
and	O
edit	O
,	O
and	O
suit	O
myriad	O
purposes	O
in	O
an	O
uncomplicated	O
way	O
.	O
</s>
<s>
Linear	O
stores	O
of	O
NoSQL	O
data	O
,	O
JSON	B-General_Concept
formatted	O
data	O
,	O
primitive	O
spreadsheets	B-Application
(	O
perhaps	O
comma-separated	O
or	O
tab-delimited	B-Protocol
)	O
,	O
and	O
text	B-General_Concept
files	I-General_Concept
can	O
all	O
be	O
seen	O
as	O
flat-file	B-Application
databases	I-Application
,	O
because	O
they	O
lack	O
integrated	O
indexes	O
,	O
built-in	O
references	O
between	O
data	O
elements	O
,	O
or	O
complex	O
data	O
types	O
.	O
</s>
<s>
Programs	O
to	O
manage	O
collections	O
of	O
books	O
or	O
appointments	O
and	O
address	B-Operating_System
book	I-Operating_System
may	O
use	O
essentially	O
single-purpose	O
flat-file	B-Application
databases	I-Application
,	O
storing	O
and	O
retrieving	O
information	O
from	O
flat	B-Application
files	I-Application
unadorned	O
with	O
indexes	O
or	O
pointing	O
systems	O
.	O
</s>
<s>
While	O
a	O
user	O
can	O
write	O
a	O
table	O
of	O
contents	O
into	O
a	O
text	B-General_Concept
file	I-General_Concept
,	O
the	O
text	B-General_Concept
file	I-General_Concept
format	I-General_Concept
itself	O
does	O
not	O
include	O
a	O
concept	O
of	O
a	O
table	O
of	O
contents	O
.	O
</s>
<s>
When	O
a	O
database	B-Application
system	I-Application
begins	O
to	O
recognize	O
and	O
codify	O
relationships	O
between	O
records	O
,	O
it	O
begins	O
to	O
drift	O
away	O
from	O
being	O
"	O
flat	O
,	O
"	O
and	O
when	O
it	O
has	O
a	O
detailed	O
system	O
for	O
describing	O
types	O
and	O
hierarchical	O
relationships	O
,	O
it	O
is	O
now	O
too	O
structured	O
to	O
be	O
considered	O
"	O
flat.	O
"	O
</s>
<s>
The	O
following	O
example	O
illustrates	O
typical	O
elements	O
of	O
a	O
flat-file	B-Application
database	I-Application
.	O
</s>
<s>
The	O
data	O
arrangement	O
consists	O
of	O
a	O
series	O
of	O
columns	O
and	O
rows	O
organized	O
into	O
a	O
tabular	B-Application
format	I-Application
.	O
</s>
<s>
This	O
type	O
of	O
data	O
representation	O
is	O
quite	O
standard	O
for	O
a	O
flat-file	B-Application
database	I-Application
,	O
although	O
there	O
are	O
some	O
additional	O
considerations	O
that	O
are	O
not	O
readily	O
apparent	O
from	O
the	O
text	O
:	O
</s>
<s>
Such	O
restrictions	O
are	O
usually	O
established	O
by	O
convention	O
,	O
but	O
not	O
formally	O
indicated	O
unless	O
the	O
data	O
is	O
transferred	O
to	O
a	O
relational	B-Application
database	I-Application
system	O
.	O
</s>
<s>
Another	O
common	O
convention	O
is	O
to	O
separate	O
columns	O
using	O
one	O
or	O
more	O
delimiter	B-Algorithm
characters	O
,	O
such	O
as	O
a	O
tab	B-Protocol
or	O
comma	O
.	O
</s>
<s>
Relational	B-Algorithm
algebra	I-Algorithm
:	O
Each	O
row	O
or	O
record	O
in	O
the	O
above	O
table	O
meets	O
the	O
standard	O
definition	O
of	O
a	O
tuple	B-Application
under	O
relational	B-Algorithm
algebra	I-Algorithm
(	O
the	O
above	O
example	O
depicts	O
a	O
series	O
of	O
3-tuples	O
)	O
.	O
</s>
<s>
Additionally	O
,	O
the	O
first	O
row	O
specifies	O
the	O
field	B-Application
names	O
that	O
are	O
associated	O
with	O
the	O
values	O
of	O
each	O
row	O
.	O
</s>
<s>
Database	B-Application
management	I-Application
system	I-Application
:	O
Since	O
the	O
formal	O
operations	O
possible	O
with	O
a	O
text	B-General_Concept
file	I-General_Concept
are	O
usually	O
more	O
limited	O
than	O
desired	O
,	O
the	O
text	O
in	O
the	O
above	O
example	O
would	O
ordinarily	O
represent	O
an	O
intermediary	O
state	O
of	O
the	O
data	O
prior	O
to	O
being	O
transferred	O
into	O
a	O
database	B-Application
management	I-Application
system	I-Application
.	O
</s>
