►
From YouTube: Blockchain Design Patterns: Academia Meets Enterprise - Aneena Ann Alexander & Arun S M
Description
Blockchain Design Patterns: Academia Meets Enterprise - Aneena Ann Alexander, Saintgits College of Engineering, Kerala & Arun S M, Walmart Global Tech India
Design patterns provide a framework for solving known problem statements. Blockchain proves to be useful and revolutionary in various industries and use cases including but not limited to Supply Chain, Trade Finance, CBDCs, Health care, etc.The major architectural consideration for blockchain-based software applications is, what data and smart contracts should be kept on-chain and what should be kept off-chain. A random design pattern causes tradeoffs among quality attributes. The patterns of the known real-world use cases, from the problem statements to discussions on what makes the problem difficult, its solutions and consequences, and the possible ways to design around multiple platforms and Hyperledger DLTs will be discussed.In addition to that, we also identify the governance design process that could be adopted by someone who is deploying a business in a blockchain network.
To learn more about Hyperledger, the open source community focused on developing a suite of stable frameworks, tools and libraries for enterprise-grade blockchain deployments. Which serves as a neutral home for various distributed ledger frameworks including Hyperledger Fabric, Sawtooth, Indy, as well as tools like Hyperledger Caliper and libraries like Hyperledger Ursa click here: https://www.hyperledger.org/
Session Details & Slides (if available)- https://sched.co/j3fA
Access All Sessions: https://events.linuxfoundation.org/hyperledger-global-forum/program/schedule/
----
Hyperledger – Open Source Blockchain Technologies
Hyperledger is an open source community focused on developing a suite of stable frameworks, tools and libraries for enterprise-grade blockchain deployments.
It serves as a neutral home for various distributed ledger frameworks including Hyperledger Besu, Fabric, Sawtooth, Indy, as well as tools like Hyperledger Avalon, Cactus and libraries like Hyperledger Aries, Ursa. Learn more about Hyperledger projects: https://www.hyperledger.org/use
Case Studies: https://www.hyperledger.org/learn/case-studies
Training & Certification: https://www.hyperledger.org/learn/training
Tutorials: https://www.hyperledger.org/use/tutorials
Webinars: https://www.hyperledger.org/learn/webinars
Events: https://www.hyperledger.org/events
Vendor Directory: https://www.hyperledger.org/use/vendor-directory
Subscribe to the Hyperledger Newsletter: https://www.hyperledger.org/newsletter
Follow-us on Twitter @Hyperledger
Learn about Hyperledger Membership: https://www.hyperledger.org/about/join
#Hyperledger #HyperledgerGlobalForum2021 #Blockchain
A
I
will
be
starting
in
a
while,
and
I
know
this
is
the
last
session
of
of
I
mean
of
this
region,
and
it's
been
like
there
were
so
many
interesting
sessions
so
far.
I
know
you
are
like
oh
one
more
station
and
then
no
boring
station.
We
we
have
put
together
an
interesting
site
of
slide
deck
in
this
presentation.
A
In
fact,
this
started
as
like
conversation
with
anina
wright,
so
we
were
discussing
on
some
of
the
use
cases
like.
I
was
asking
questions
on
hey.
How
does
it
solve
from
academic
word,
and
then
there
were
questions
back
on.
How
can
we
implement
this?
Then
we
both
sat
together
and
put
our
thoughts
on
on
this
slide
deck
and
that's
what
we're
going
to
present
in
today's
session.
A
A
A
Okay,
so,
meanwhile
we'll
be
presenting
the
topic
of
blockchain
design
patterns
where
we'll
be
discussing
advantages
and
disadvantages
of
some
of
the
commonly
known
patterns
and
then
from
academic
point
of
view,
what
really
works
and
what
doesn't
work.
And
where
is
that
research
gap
that
that
we
still
need
to
proceed
in
right?
B
B
B
We
will
be
taking
a
deep
dive
into
on-chain
and
off-chain
world
data
and
interactions,
and
the
other
area
that
we
are
going
to
touch
is
data
versus
network
earnings
and
yeah.
We
have
a
lot
to
go
through
and
hand
this
off
to
arun
and
he
will
be
discussing
the
common
patterns
used
in
application
development.
A
Right,
I'm
sure
most
of
us
are
have
come
from
application
development
background
who
we
have
been
developing
multiple
applications
right.
So
whenever
we
think
about
web
application,
we
will
have
a
database
stored
in
our
enterprise
systems
and
then
we
will
build
back
an
engine.
It
could
be
microservice
architecture
which
is
talking
to
these
database
databases,
and
when
we
talk
about
database
again,
it
could
be
like
a
single
instance
of
database
like
which
is
monolithic,
storage
or
it
could
be
again
distributed
database.
A
Storing,
maybe
shards
of
data
are
maybe
distributed
across
multiple
regions
for
different
optimizations
applied
for
multiple
geo
locations,
and
then
we
will
have
kind
of
typical
user
interface,
which
is
talking
to
these
back-end
services
and
which
is
finally
accessed
by
the
user.
But
does
this
really
work
in
blockchain
case
right?
So
that's
the
question
and
even
in
in
general
web
applications.
A
We
have
something
called
as
like:
we,
we
do
implement
authentication
and
authorization
mechanism
at
the
backend
apis
layer
and
we
relay
those
requests
to
network
gateways,
but
when
we
apply
that
to
blockchain
technology
right
and
many
people,
if,
if
you're
like
unfamiliar
with
it,
blockchain
does
provide
storage,
and
if
you
consider
blockchain
itself
as
a
storage
engine,
then
you
try
to
directly
replace
what
we
have
in
our
traditional
web
application
with
blockchain.
That
may
really
not
work,
because
when
we
send
a
write
request
right,
let's
take
a
typical
database
application.
A
When
I
send
a
write
request,
those
write
requests
would
be.
Then,
can
you
go
back
to
previous
slides?
Let's,
let's
take
a
typical
application
right
when
we
send
the
write
request
to
database.
Those
write.
Requests
will
not
be
committed
until
we
say
commit
this
particular
data
to
a
database
application.
A
So,
similarly,
if
you
consider
blockchain
operations,
you
can
consider
a
transaction
execution
or
that
particular
phase
where
blockchain
decides
whether
to
process
process,
the
transaction
or
not
to
be
first
phase
and
then
the
commit
phase
where
in
term,
if
you
have
to
talk
in
terms
of
hyperledger
fabric,
that's
when
ordering
service
comes
together
and
it
gets
involved
and
creates
the
block.
So
if
the
block
gets
accepted,
that's
the
commit
phase
for
us
right.
A
So
this
is
how
we
can
correlate
a
db
write
versus
a
blockchain
write
operation
and
the
smart
contract
is,
is
the
one
which
is
going
to
perform
the
crud
operations
onto
database,
but
we
are
really
not
sure
how
long
it
takes
for
that
particular
block
to
get
created,
and
how
long
that
that
particular
operation
to
be
completed,
because
transaction
execution
happens
at
its
own
phase,
we
cannot
really
guarantee
and
then
having
this
kind
of
application
design.
Is
it's
not
generally
preferred
right?
A
So
now,
let's
look
at
an
alternate
to
that,
so
we
said
we
will
not
be
able
to
design
our
blockchain
application
as
if
it
is
a
database
a
system.
Now
what
what
can
we
improve
over
it?
Let's
say
we
we
bring
in
like
for
every
request.
We
bring
in
immediate
response,
saying
that,
okay
now
I
am,
this
is
my
back
end
up
back
in
engine
which
is
also
acting
as
a
blockchain
client
node
for
my
actual
blockchain
applications
or
the.
A
A
Like
blockchain
note,
it
not
only
affects
the
blockchain
node
in
terms
of
long
wait
which
we
have
to
do,
but
it
also
has
its
own
effect
that
smart
contract
may
never
get
executed
or
may
continue
in
the
in
the
loop
of
failures
right.
So
until
until
that
point
we
will
not
be
able
to
keep
users
waiting.
If
this
was
my
payment
application
based
on
blockchain.
I
cannot,
when
user
says,
pay
this
thing
to
somebody
else.
A
A
So
in
this
approach,
what
we
have
done
is
put
a
cache
database
in
between
blockchain
and
our
client
node,
which
is
also
our
backend
application,
and
in
addition
to
that,
we
have
something
called
as
event
listener.
So
what
this
event
listener
does
is
any
blockchain
you
take
fabric
sawtooth
or
base
or
anything
there
is
a
concept
of
transaction
receipt
or
like
event
at
multiple
layers.
It
could
be
at
block
level,
it
could
be
a
commit
level
or
it
could
be
a
channel
level
in
fabric.
A
So
what
we
can
do
is
we
can
ask
blockchain
system
itself?
Hey,
I
send
you
a
transaction,
you
tell
me
when
it
is
completed
or
you
keep
telling
me
information
whatever
is
happening
within
you
and
based
on
that
I'll
I'll
make
my
decisions
I'll
do
something
at
the
application
layer.
So
that's
what
this
system
indicates
and
what
is
cached
to
be
used
for
so
cache
db
in
here
is
like
when
I
receive
a
transaction,
I
need
to
first
store
it
somewhere,
so
that
I
don't
lose
my
data.
A
So
let's
say
I
have
some
temporary
storage
it
could
be.
It
could
also
be
like
a
pub
sub
topic
like
like
a
kafka
engine
which
which
can
store
data
for
three
days
or
five
days
or
ten
days
right.
So
let's
say
I
cache
all
the
requests
and
I
stream
them
from
this
blockchain
client
into
blockchain
at
its
own
phase,
and
whenever
I
receive
data
from
the
blockchain,
I
tell
it
to
user.
Hey
here
is
the
current
status
of
whatever
you
did
earlier,
but
probably
this
is
also
not
not
sufficient.
A
This
is
good,
but
this
is
not
sufficient
model
for
us.
What?
If
user,
wants
to
query
what
happened
with
their
data
in
the
past?
Like
there
is
no
way
that,
because
we
are
just
streaming,
requests
streaming
solutions
from
blockchain
and
giving
it
back
to
user,
there
is
no
way
we
can
know
what
happened
in
the
past.
So
that's
where
we
have
our
next
architecture
pattern,
which
is
like,
in
addition
to
having
event
listener.
We
what
if
we
store
the
event,
listener
data
into
another
database.
A
Now
there
are
multiple
advantages
here
and,
of
course,
like
backend
engine
can
be
used
to
perform
retry
operations
on
the
failing
data.
It
can
know
what
what
failed
and
what
not
fair,
based
on
the
event
listeners
data,
and
in
addition
to
that
this
I
mean
I'm
calling
it
as
analytics
data
over
there.
But
the
reason
for
calling
that
is
when
we
receive
events
from
blockchain.
A
So,
with
this
approach,
we
have
local
cache
of
information
as
and
when
transactions
arrive.
We
are
caching
them,
we
are
sending
them
to
blockchain.
We
are
waiting
for
blockchain
commit
operations
to
complete,
and
then
we
are
also
having
analytics
database
and
then
a
query
mechanism
or
repurposing
that
analytics
database
to
perform
any
other
operations
that
we
require
right
now.
A
One
more
thing
which
I
would
like
to
call
out
here
is
that
in
in
terms
of
that
cache
database
in
in
in
the
diagram
with
the,
if
you
consider
the
cache
database,
if
you
replace
that
with
some
kind
of
permanent
storage,
we
can
also
use
this
design
pattern.
As
off-chain
storage
of
our
data,
I
don't
need
to
put
everything
onto
my
blockchain.
A
A
If
these
databases
are
in
protected
environment
because
it
is
for
their
own
usage,
we
really
don't
need
anything
extra.
That's
all
we
need,
but
on
few
cases
we
may
need
to
audit
the
data
which
is
stored
over
there.
So
that's
where
we
can
bring
in
additional
component,
let's
say
a
scheduled
data
verifier,
which
I'm
calling
it
over
here,
but
in
reality
it
is.
It
is
an
audit
module.
So
what
exactly
are
we
auditing?
Here?
A
Let's
say
you
randomly
pulled
some
data
from
your
analytics
data
or
whatever
you
read
from
blockchain,
and
then
you
try
to
query
your
blockchain
in
your
laser
time
when
your
payload
or
when
your
throughput
requirements
are
low
and
whenever
your
blockchain
node
is
capable
enough
to
answer
all
those
sample
data,
queries
and
audit
them
through
this
module.
So
with
this
approach
I
mean,
as
soon
as
you
identify
there
is
some
screen.
There
is
some
change
in
data
against
whatever
you
stored
off
chain.
A
You
will,
of
course,
do
that
analysis
separately
right.
So
what
happened
like
who
changed
it?
What
actually
happened
on
your
on
to
your
external
database,
but
this
process
of
auditing
will
allow
you
to
not
only
identify
but
also
rebuild
the
replay,
whatever
happened
earlier
so
most
of
the
blockchain
solutions.
They
do
have
option
for
you,
where
you
can
ask
it
hey.
I
don't.
I
want
to
know
what
exactly
happened
from,
let's
say:
block
number
10.
A
I
want
to
know
what
happened
from
block
number
12.,
so
there
the
event
mechanism
in
in
in
most
of
the
blockchain
solutions
they
provide
you
that
option.
You
can
replay
it
from
particular
block
to
particular
block,
when
maybe,
let's
say
from
block
number
10
to
latest
block
and
re
rebuild
your
database.
So
you
can
you
can
process
your
off
chain
data
as
if
you
can,
you
can
now
again
start
trusting
that
database.
A
B
So
thanks
arun,
so
let's
dive
into
the
benefits
and
challenges
of
this
architecture.
First,
so
this
micro
services
usually
kind
of
satisfy
the
increasing
need
for
a
more
fluid
flow
of
information
so
coming
to
our
benefits.
First,
so
event
based
architectures
are
usually
asynchronous
without
blocking,
so
this
actually
enables
the
resources
to
jump
freely
to
the
next
task
once
their
piece
of
work
is
actually
complete
without
worrying
about
what
happened
before
or
what
will
be
happening.
Next
and
services
are
usually
loosely
coupled.
B
That
means
they
generally
do
not
need
to
have
a
knowledge
or
they
do
not
have
any
dependencies
on
other
services,
including
their
implementation,
details
or
any
other
transport
protocols,
and
it's
generally
easy
to
scale
using
microservices.
Maybe
you
can
increase
the
resources
to
the
most
needed
micro
services
rather
than
scaling
an
entire
application,
and
this
actually
enables
scaling
to
be
a
bit
faster
and,
of
course
it
will
be
cost
efficient
as
well.
B
So
when
we
are
using
it
with
a
queue,
it
can
actually
kind
of
recover
the
lost
work
by
something
called
replaying,
and
you
know
this
can
be
really
valuable
to
prevent
data
loss
when
a
consumer
needs
to
recover
data.
So,
of
course,
with
never-ending
list
of
benefits.
Event-Driven
architectures
have
some
challenges
as
well.
So
the
first
challenge
that
I
personally
think
is.
B
B
There
can
be
questions
on
security,
there
can
be
questions
on
privacy
and,
of
course,
there
can
be
questions
on
cost,
so
maybe
to
circle
around
it.
Actually,
I
would
like
to
bring
your
attention
to
something
called
blockchain
trauma.
So
usually
it
is
explained
in
context
of
public
blockchains,
so
the
public
blockchain
dilemmas
are,
it's
also
called
impossible.
Triangles
so
it's
the
idea
that
a
blockchain
can
have
decentralization,
it
can
have
security
and
it
can
have
scalability
to
varying
degrees,
but
it
cannot
have
all
the
three
to
that
sufficient
extent
at
the
same
time.
B
So
what
I
mean
by
scalability
here,
transaction
performing
transaction
processing
performance
that
is
tps.
That
is
the
number
of
transaction
process
per
second.
So
maybe
I
can
take
an
example
say,
for
example,
if
you're
considering
the
example
of
a
bitcoin,
it
is
widely
considered
to
succeed
in
security
having
never
been
hacked,
and
you
know
decentralization
both
in
governance
and
development,
but
coming
to
scalability
due
to
its
limited
block
size
and
comparatively
long
block
time.
It
is
actually
compromising
that
thing.
B
So,
in
short,
every
application
is
expected
to
have
all
these
three
things,
but
it
cannot
have
all
the
three
at
the
sufficient
extent
at
the
same
time.
Okay,
so
maybe
we
can
move
to
a
real
life
use
case
and
we
are
actually
quoting
this
from
the
official
documentation
of
hyperledger
fabric,
so
agriculture
is
actually
providing
likelihood
to.
You
know
more
than
50
percentage
of
the
people
in
developing
countries,
especially
like
india,
but
you
know,
climate
change
is,
at
the
same
time
passing
grave
risk
to
their
activities
as
well.
B
Maybe
you
know
the
slightest
increase
in
the
frequency
of
a
drought
or
if,
if
there
is
an
increase
in
grain,
it
will
actually
present
major
challenges
for
food
security
and
water
availability
to
them
and
to
the
question
on
how
this
payout
is
actually
made.
Usually
the
agreement
actually
exists
between
the
insurer
and
the
insured
under
specific
threshold
weather
condition
when
I
say
weather
conditions,
it
can
be.
You
know,
consecutive
days
with
or
without
rain,
or
something
like
that.
B
So,
if
you're
thinking
for
a
moment
who
can
add
those
information,
I
mean
who
can
add
those
weather
data?
Is
that
the
farmers?
No,
they
cannot
add.
That
is
that
the
insurance
companies
are
big.
No
is
that
a
third
party,
so
academically
or,
theoretically
speaking,
it
is
possible
if
we
can
introduce
a
trusted
third
party,
like
the
meteorological
department,
because
they
can
provide
the
needed
legit
information
and
what,
if
they
are
not
willing
to
join
the
network,
then
how
can
we
make
payouts?
Then?
What
is
the
solution?
B
So
all
of
you
might
be
aware
of
what
a
smart
contract
is,
so
smart
contracts
are
just
pieces
of
code,
or
you
know,
business
logic
that
actually
live
on
blockchain
and
they
execute
on
certain
conditions
on
logic
that
smart
contract
developers
has
built,
and
the
main
focus
is
here
on
data,
without
good
data
to
make
decisions
on
what
happens
or
what
transactions
should
execute.
This
smart
contract
cannot
work
on
the
way
it
is
intended
to
work.
B
B
So
maybe
we
can
come
back
to
our
example
and
see
how
oracles
can
solve
this
problem?
Okay,
so
we
can
simply
put
oracles
as
trusted
third
party,
that
actually
supplies
data
to
blockchain,
so
maybe
for
a
smart
decision
if
the
information
is
added
by
a
trusted.
Third
party,
like
you,
know,
oracle's
in
the
form
of
data
concerning
the
conditions
like
you
know,
concerning
the
weather
conditions,
the
payouts
can
be
automatically
triggered
and
the
insurance
company
or
insured
party
cannot
intervene
to
stop
the
payments
or
you
know,
change
the
conditions.
B
So
basically,
this
goes
like
this.
Oracle
is
required
to
perform
some
sort
of
action
as
a
trusted
data
source
and
they
can
have
the
ability
to
reconcile
multiple
data
sources
and
feed
them
as
one
stream
of
data.
So
when
I
say
reconciliation,
it
can
be.
You
know
different
methods
like
weighted
averages
or
it
can
be
based
on
reputation,
scores
or
it
can
be
based
on
complex
cryptography.
So
oracles
are
basically
it
can
be
considered
as
gatekeepers.
B
So
maybe
we
can
think
we
can
put
in
another
way
as
a
blockchain
subjective
is
to
reach
consensus.
You
know
extrinsic
information.
We
cannot.
You
know
provide
along
with
the
transaction
data,
because
other
date,
other
nodes
would
actually
dictate
information
coming
from
an
untrusted
source
right.
So,
therefore,
the
information
coming
from
the
real
world
should
come
from
a
party
which
is
a
univocal
source
whose
reliability
is
undisputed
for
all
the
nodes
and
the
oracles.
B
So
when,
when
what?
When
smart
contracts
concerning
this
extrinsic
data
is
kind
of
executed,
the
court
then
calls
for
the
right
information
from
a
trusted
articles
and
yeah
it
gets
executed.
Maybe
the
examples
of
oracle's
can
be.
You
know,
iot
systems
such
as
props
or
sensors,
or
they
can
be
even
humans
that
operates
directly
on
the
blockchain,
so
maybe
coming
and
and
then
we
can
come
to
the
different
types
of
oracles.
B
Oracles
are
usually
classified
into
two
main
categories:
the
first
one
can
be
a
centralized
oracle
and
the
second
one
can
be
a
decentralized
oracle,
so
centralized,
as
a
name
suggests.
It
means
that
one
particular
data
source
or
api
is
having
the
control
over
your
smart
contract
and
if,
if,
if
it
is
happening
like
that
there
is
your
smart
contract
is
now
no
better
than
a
regular
contract
right.
B
So
if
you
are
using
centralized
particles
that
are
not
distributed,
they
can
actually
introduce
single
point
of
failure
and
they
can
actually,
you
know,
since
they
are
operating
on
non-deterministic
data.
Their
reliability
needs
to
be
trusted
where
availability,
accessibility
and
level
of
certainty
about
the
validity
of
the
data
actually
depends
only
on
one
node.
When
we
are
actually
coming
to
decentralized
articles,
it
can
be
considered
as
a
group
of
independent
blockchain
oracles
that
provide
data
to
the
blockchain,
so
every
independent
node
or
oracle
in
the
decentralized
network.
B
Actually,
you
know
independently
retrieves
data
from
an
off
chain
source
and
bring
it
to
the
chain,
and
the
data
is
then
aggregated,
and
you
know
so.
The
system
can
come
to
the
deterministic
value
of
truth.
For
that
data
points,
maybe
there
are
different.
As
I
mentioned
earlier,
there
are
different
reconciliation
techniques.
Maybe
we
can
use
any
one
kind
of
any
any
of
them
and
we
can
come
to
a
deterministic
value
of
truth.
B
For
that
particular
data
point,
and
if
you
are
actually
migrating
to
decentralized
articles,
it
can
resolve
the
single
point
of
failure
problem
in
the
centralized
truss
model,
but
these
models
can
actually
bring
higher
latency
for
the
data
processing
with
less
efficiency
when
compared
with
the
centralized
data
model.
Okay.
B
So
when,
if
we
are
actually
fetching
data
from
an
external
source,
the
trilemma
or
impossible
triangle
can
be
redefined
as
while
fetching
a
data
from
an
external
source.
A
system
can
have
decentralization
accuracy
and
it
can
satisfy
cost,
but
only
to
varying
degrees,
but
it
cannot
have
all
the
three
to
that
sufficient
extent
at
the
same
time.
B
Okay,
so
basically,
our
discussions
around
oracle's
showed
that
achieving
a
fully
trustworthy
oracle
platform
for
blockchain
is
still
at
an
early
stage
and
it
requires
more
research
attention
and
you
know,
efforts
need
to
be
exerted
in
this
direction.
So
specifically,
we
need
to
integrate.
You
know
novel
security
and
privacy
mechanisms
to
interrupt
to
the
existing
trust
models,
maybe
to
detect,
prevent
and
mitigate
some
symbol
and
collusion
among
oracles
to
solve
this
design
and
implementation
challenges,
and
maybe
we
can.
B
We
can
actually
try
for
establishing
new
standards
for
unified
data
format,
formats
and
decentralized
covenants.
So,
having
this
in
mind
as
blockchain
grows
in
popularity
and
adoption
becomes
more
mainstream,
the
question
of
governance
is
still
a
concern
and
you
know
the
governance
can
give
them
the
voice
and
control
that
they
are
actually
comfortable
with.
So
maybe
I
can
quickly
call
arun
and
he's
a
better
person
to
portray
the
governance
designs
patterns
so
over
to
arun.
A
Surely
now
so
I
I
guess
this,
this
is
a
great
discussion.
So
far
like
we
started
with
some
come
off
some
of
the
common
design
patterns.
We
looked
into
and
scenario
where
hey.
This
is
the
only
way
in
which
data
from
external
source
is
the
only
way
in
which
this
we
can
proceed
from
there
to
make
a
smart
contract
decision,
and
so
I
mean
I
would
put
this
entire
process.
If
you
can
go
to
next
slide
right.
I
would
put
this
entire
process
itself
as
a
data.
A
Governance
related
concern
right,
so
whatever
we
we
are
following
following
those
best
practices
in
terms
of
design
following
those
best
guidelines
in
terms
of
choosing
right
model
for
putting
the
data
right
right
data
into
the
system,
so
I
would
put
that
into
data
governance
aspect
right,
and
why
do
we
need
that?
Because
of
not
just
for
securing
our
own
data,
but
also
because
there
would
be
regulatory
requirements?
It
would
require
us
to
maybe
protect
the
data
in
certain
ways
or
restrict
access
to
that
data,
or
maybe
restrict
from
processing
that
particular
data.
A
The
way
they
want,
or
maybe
even
make
modification
or
retention
related
policies,
so
I
mean
I
would
put
these
things
aside
for
a
while,
and
if
you,
if
you
see
apart
from
data
governance,
there
is
also
one
more
important
aspect
that
we
will
need
to
consider
with
oracle
patterns
right
so
with
oracle
patterns.
Some
of
the
good
practices
that
we
have
oracle
service
provider
smart
contract
running
in
our
blockchain
system
and
which
has
the
only
access
to
external
services,
anything
that
our
smart
contract
requires
will
talk
to
this
particular
smart
contract.
A
And
then,
let's
say
if
this
was
a
fabric
network,
we
have
a
channel
where
all
the
consortium
members
are
part
of,
and
then
there
is
another
channel
where
we
are
allowing
oracle
service
provider
to
join
in
and
provide
the
external
data
source
to
us.
But
the
important
aspect
with
this
is
how
well
we
manage
this
network
itself,
so
network
governance
is
very
critical
over
there.
Along
with
data
governance,
I
mean
the
diagram
is,
is
more
intuitive
than
what
I
would
what
I
could
express
right.
A
We
need
to
restrict
access
from
from
these
services
in
inbound
traffic
from
these
services.
There
should
be,
it
should
be
more
of
outbound
traffic.
I
mean
requests
which
are
which
can
be
made
from
consortium
members
than
inbound
requests
coming
in
from
oracle
service
providers.
So,
with
with
these
thoughts,
I
mean
this
this
com.
This
puts
a
picture
around.
How
can
we,
in
the
I
mean
when
we
started
how
we
started
with
the
design
patterns?
A
B
A
You
I
see
a
question
which
says
what
are
recommendations
for
query
from
blockchain
based
systems,
so
this
is
a
great
question.
I
know
many
people
have
this
question,
so
it
depends
on
the
trash
boundary.
I
mean
you
could
of
course,
directly
read
from
the
let's
in
in
this
case,
I'm
assuming
you
have
external
database
like
externally
installed
couch
database
or
your
peer
in
hyperledger
fabric.
You
could
directly
read
that,
but
it
depends
on
trust
boundary.
A
If,
if
your
trust
boundary
is
such
that
you
are
the
only
party
who
can
access
that
database
and
of
course
you
are
free
to
do
that.
However,
it's
always
better
that
we
have
like
external
copy
of
data.
The
way
we
want
right
so
because
the
let's
say,
even
when
block
pruning
kind
of
concept
comes
in
not
when,
where
we
want
to
stop
the
blockchain
or
maybe
like
archive
a
blockchain
for
certain
period
of
time,
the
old
data
still
plays
significant
roles
for
analytic
purpose.
A
I
see
another
question:
do
you
think
a
chain
code
could
be
used
as
decentralized
practical,
if
not
enough
in
your
society,
and
the
value
transaction
would
fail
preventing
condition
right?
So
if
you,
if
you
remember
the
diagram
which
we
were
showing
and
in
that,
we
showcased
one
of
the
way
in
which
oracle's
can
be
designed,
where
we
have
a
smart
contract,
specific
smart
contract
or
specialized
smart
contract,
which
is
going
to
help
read
external
data,
so
you
could
of
course
convert.
A
I
mean
this
smart
contract
could
be
implemented
in
any
protocol
or
in
any
language,
including
the
chain
code
way
of
reading
external
data
and
chain
code.
In
fact,
I
mean
helps
you
in
governing
it
much
better
right.
You
can
you
not
only
are
agreeing
upon
majority,
but
you
could
also
put
measures
such
that
hey.