<s>
Extract	B-General_Concept
,	I-General_Concept
load	I-General_Concept
,	I-General_Concept
transform	I-General_Concept
(	O
ELT	O
)	O
is	O
an	O
alternative	O
to	O
extract	O
,	O
transform	O
,	O
load	O
(	O
ETL	O
)	O
used	O
with	O
data	B-General_Concept
lake	I-General_Concept
implementations	O
.	O
</s>
<s>
In	O
contrast	O
to	O
ETL	O
,	O
in	O
ELT	O
models	O
the	O
data	O
is	O
not	O
transformed	O
on	O
entry	O
to	O
the	O
data	B-General_Concept
lake	I-General_Concept
,	O
but	O
stored	O
in	O
its	O
original	O
raw	O
format	O
.	O
</s>
<s>
However	O
,	O
ELT	O
requires	O
sufficient	O
processing	O
power	O
within	O
the	O
data	B-General_Concept
processing	I-General_Concept
engine	O
to	O
carry	O
out	O
the	O
transformation	O
on	O
demand	O
,	O
to	O
return	O
the	O
results	O
in	O
a	O
timely	O
manner	O
.	O
</s>
<s>
Since	O
the	O
data	O
is	O
not	O
processed	O
on	O
entry	O
to	O
the	O
data	B-General_Concept
lake	I-General_Concept
,	O
the	O
query	O
and	O
schema	O
do	O
not	O
need	O
to	O
be	O
defined	O
a	O
priori	O
(	O
although	O
often	O
the	O
schema	O
will	O
be	O
available	O
during	O
load	O
since	O
many	O
data	O
sources	O
are	O
extracts	O
from	O
databases	O
or	O
similar	O
structured	O
data	O
systems	O
and	O
hence	O
have	O
an	O
associated	O
schema	O
)	O
.	O
</s>
<s>
ELT	O
is	O
a	O
data	B-General_Concept
pipeline	I-General_Concept
model	O
.	O
</s>
