<s>
Query	B-Application
by	I-Application
Example	I-Application
(	O
QBE	O
)	O
is	O
a	O
database	B-Language
query	I-Language
language	I-Language
for	O
relational	B-Application
databases	I-Application
.	O
</s>
<s>
It	O
was	O
devised	O
by	O
Moshé	O
M	O
.	O
Zloof	O
at	O
IBM	O
Research	O
during	O
the	O
mid-1970s	O
,	O
in	O
parallel	O
to	O
the	O
development	O
of	O
SQL	B-Language
.	O
</s>
<s>
It	O
is	O
the	O
first	O
graphical	O
query	B-Language
language	I-Language
,	O
using	O
visual	O
tables	O
where	O
the	O
user	O
would	O
enter	O
commands	O
,	O
example	O
elements	O
and	O
conditions	O
.	O
</s>
<s>
Originally	O
limited	O
only	O
for	O
the	O
purpose	O
of	O
retrieving	B-Application
data	I-Application
,	O
QBE	O
was	O
later	O
extended	O
to	O
allow	O
other	O
operations	O
,	O
such	O
as	O
inserts	O
,	O
deletes	O
and	O
updates	O
,	O
as	O
well	O
as	O
creation	O
of	O
temporary	O
tables	O
.	O
</s>
<s>
The	O
motivation	O
behind	O
QBE	O
is	O
that	O
a	O
parser	B-Language
can	O
convert	O
the	O
user	O
's	O
actions	O
into	O
statements	O
expressed	O
in	O
a	O
database	O
manipulation	O
language	O
,	O
such	O
as	O
SQL	B-Language
.	O
</s>
<s>
A	O
suitably	O
comprehensive	O
front-end	O
can	O
minimize	O
the	O
burden	O
on	O
the	O
user	O
to	O
remember	O
the	O
finer	O
details	O
of	O
SQL	B-Language
,	O
and	O
it	O
is	O
easier	O
and	O
more	O
productive	O
for	O
end-users	O
(	O
and	O
even	O
programmers	O
)	O
to	O
select	O
tables	O
and	O
columns	O
by	O
selecting	O
them	O
rather	O
than	O
typing	O
in	O
their	O
names	O
.	O
</s>
<s>
In	O
the	O
context	O
of	O
information	B-Library
retrieval	I-Library
,	O
QBE	O
has	O
a	O
somewhat	O
different	O
meaning	O
.	O
</s>
<s>
Currently	O
,	O
QBE	O
is	O
supported	O
in	O
several	O
relational	B-Application
database	I-Application
front	O
ends	O
,	O
notably	O
Microsoft	B-Application
Access	I-Application
,	O
which	O
implements	O
"	O
Visual	O
Query	B-Application
by	I-Application
Example	I-Application
"	O
,	O
as	O
well	O
as	O
Microsoft	O
SQL	B-Language
Server	O
Enterprise	O
Manager	O
.	O
</s>
<s>
It	O
is	O
also	O
implemented	O
in	O
several	O
object-oriented	B-Application
databases	I-Application
(	O
e.g.	O
</s>
<s>
in	O
db4o	B-Language
)	O
.	O
</s>
<s>
QBE	O
is	O
based	O
on	O
the	O
logical	O
formalism	O
called	O
tableau	O
query	B-Library
,	O
although	O
QBE	O
adds	O
some	O
extensions	O
to	O
that	O
,	O
much	O
like	O
SQL	B-Language
is	O
based	O
on	O
the	O
relational	B-Algorithm
algebra	I-Algorithm
.	O
</s>
<s>
It	O
provides	O
a	O
way	O
for	O
a	O
software	O
user	O
to	O
perform	O
queries	B-Library
without	O
having	O
to	O
know	O
a	O
query	B-Language
language	I-Language
(	O
such	O
as	O
SQL	B-Language
)	O
.	O
</s>
<s>
The	O
software	O
can	O
automatically	O
generate	O
the	O
queries	B-Library
for	O
the	O
user	O
(	O
usually	O
behind	O
the	O
scenes	O
)	O
.	O
</s>
<s>
Resulting	O
SQL	B-Language
:	O
</s>
<s>
Note	O
how	O
blank	O
items	O
do	O
not	O
generate	O
SQL	B-Language
terms	O
.	O
</s>
<s>
Resulting	O
SQL	B-Language
:	O
</s>
<s>
Another	O
approach	O
to	O
text	O
comparisons	O
is	O
to	O
allow	O
one	O
or	O
more	O
wildcard	B-Algorithm
character	I-Algorithm
characters	O
.	O
</s>
<s>
For	O
example	O
,	O
if	O
an	O
asterisk	O
is	O
designated	O
as	O
a	O
wild	O
wildcard	B-Algorithm
character	I-Algorithm
in	O
a	O
particular	O
system	O
,	O
then	O
searching	O
for	O
last	O
names	O
using	O
"	O
Rob*	O
"	O
would	O
return	O
(	O
match	O
)	O
last	O
names	O
such	O
as	O
"	O
Rob	O
"	O
,	O
"	O
Robert	O
"	O
,	O
"	O
Robertson	O
"	O
,	O
"	O
Roberto	O
"	O
,	O
etc	O
.	O
</s>
