►
Description
A recording of the Study Circle session on July 25th, 2020 hosted by Hyperledger Sweden. Roland Bole talked about Chaincode basics in Hyperledger Fabric.
Github Link : https://samlinux.at/blog/fabric-04/
More about the Study Circle sessions are at: https://www.meetup.com/Hyperledger-Sweden/
----
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A
A
What
I
have
prepared
for
you
last
week
we
have
done
a
little
bit
chain
code,
development
and
we
have
started
to
develop
a
chain
code
and
for
today's
session
I
have
extended
this
chain
code
and
I
would
like
to
show
you
some
special
topics
in
this
part.
So
the
first
thing
what
what
I
would
like
to
show
you
is
how
we
can
create
a
short
dev
network
where
we
can
use
the
build
your
first
network
example
and
install
our
own
chain
code.
A
A
So
we
will
have
an
add
function,
an
update
function
to
see
how
the
state
is
changed.
Then
the
query
functions
are
the
same
like
in
the
last
week,
and
then
I
have
in
developed
a
new
a
new
function
and
get
all
transactions
by
key.
So
I
want
for
me.
It
was
interesting
to
see
how
I
can
query
the
old
states
of
an
asset,
and
this
is
done
with
this
functionality,
and
then
the
next
step
would
be
how
I
can
query
such
a
state
from
the
history,
and
this
is
an
interesting
part.
A
So
we
can
see
here.
We
have
chain
code
operations
and
we
have
sdk
operations
and
in
my
example,
I
have
used
the
same
nodejs
application,
which
I've
used
in
the
second
meetup.
I
think-
and
I
have
also
extended
this
nodejs
application
to
do
to
do
this
operations
so
and
during
this
example,
I
have
seen
that
there
was
a
problem
for
me
to
pass
values
to
the
chain
code.
A
So,
in
all
examples
I
have
seen
is
a
string
array
where
we
test
the
single
parameters
or
the
single
values
to
the
chain
code,
and
that
is
a
little
bit
uncomfortable
and
I
have
tried
to
change
this
and
I
would
like
to
show
how
we
can
do
this,
because
these
values
are
json
for
values
in
a
json
format
and
yeah.
This
is
a
in
part
a
little,
a
little
improvement.
A
I
have
done
in
my
chain
code
and
then
through
this
operations
for
the
transactions
and
the
transaction
itself,
I've
seen.
Okay.
What
I
have
asked
me,
what
is
the
difference
between
the
key
and
the
transaction
and
that's
also
part
what
I
would
like
to
show
you
here
and,
as
I
have
mentioned
in
the
last
session,
there
were
two
questions.
A
One
question
both
related
to
the
couchdb
example:
so
how
we
can
query
sub-objects,
like
owner
the
name
of
the
owner,
address
or
something
like
this,
so
this
I
have
included
in
the
example
and
also
the
history.
So
that's
that's
the
part
where
we
can
query
the
history
from
an
asset
and
then
one
point.
A
I
have
shown
you
my
chain
code
and
in
this
chain
code
I
had
two
terror
mistakes,
and
this
mistakes
was
the
reason
why
my
endorsement
policy
failed,
and
this
is,
I
think,
a
really
really
good
example
to
know
how
something
you
don't
should
do
in
the
favorite
development
so
and
that's
about.
I
will
come
in
the
end
of
my
presentation,
so,
okay,
the
first
thing
how
we
can
create
a
dev
network
to
test
our
chain
code.
A
A
Because
I
have
modified
some
things,
so
I
have
changed
the
code
to
be
environment
variables
and
I
have
also
changed
something
for
the
development
process
and
for
this
I
have
copied
this
one.
But
important
is
a
second
folder
so
and
in
the
second
folder
I
have
created
a
short
script
and
with
this
script
we
can
start
the
builder
first
network
network
and
install
our
own
chain
code.
A
So,
and
that
means
that
we
can
use
the
picture
first
network
example
and
we
can
start
it
without
the
predefined
chain
code
and
we
can
install
our
own
chain
code.
So
this
is
the
chain
code.
I
will
show
it
a
little
bit
later
and
the
important
part
here
is:
we
can
start
the
network
and
we
have
here
three
options.
So
the
the
s
option
we
have
seen
last
week
is
for
couchdb.
So
in
my
example,
we
would
like
to
use
couchscopy
because
we
are
going
to
query
the
values
and
not
the
keys.
A
So
the
c
option
is
also
clear.
It's
the
channel
name
and
the
a
option
here
is
stands
for
certified
authority.
So
when
we
set
the
a
option,
favorite
ca
container
is
started,
so
we
need
this
for
the
node.js
application
to
enroll
a
new
user
to
add
an
existing
user
to
our
wallet
from
the
nodejs
application
that
we
can
have
access
to
the
chain
code
and
the
important
part
here
is
the
n
option.
So
that
means
no
chain
code
will
be
installed.
A
So
when
you
set
this
option
here,
then
no
chain
code
will
install
and
you
have
to
install
your
chain
code
by
your
own.
So
and
then
you
have
developed
with
the
docker
dev
mode
development
containers,
your
own
chain
code,
and
you
think
it's
ready
to
test
it
in
the
real
network.
Then
we
can
use
this
bro
procedure
and
that's
very
straightforward.
So
I've
configured
some
variables
and
then
we
have
to
call
this
docker
exec
commands.
So
we
have
to
install
the
chain
code
on
every
peer
from
both
organizations.
A
So
as
you
know
that
the
test
figure
first
network
has
two
organizations,
and
both
organizations
have
two
peers
and
0
and
pier
1,
and
on
this
piers
we
have
to
install
the
chain
code,
because
when
we
don't
install
the
chain
code
on
our
ps,
then
we
we
don't
have
an
endorsement
here.
So
we
have
only
a
committing
beer
and
the
committing
beer
can't
be
created
because
it's
it
has
no
chain
code
installed,
and
it's
only
if
you
on
this
and
this
only
for
verification
in
the
fabric
network
and
for
holding
the
blockchain.
A
So
that's
important
that
you
install
the
train
code
on
every
peer
which
you
would
like
to
query,
and
then
you
can
speak
about
the
endorsement
here
so,
but
I
think
that's
here
everything
the
same.
So
we
have
beer,
zero
spear,
one
everything
is
the
same
here
and
zero,
also
for
the
organization
2.
and
then
in
the
last
step
we
have
to
instantiate
our
smart
contract.
A
So
and
that,
but
this
to
this
I
will
come
a
little
bit
later
so
and
with
this
small
setup,
we
can
run
the
build
your
first
network
with
our
own
chain
code,
and
then
we
can
play
and
test
a
little
bit
to
yeah
to
see
how
this
works.
So
this
is
an
important,
a
helper
script.
I
think
so
so
then,
when
you
are
going
to
to
test
your
chain
code
in
a
test
environment,
so
you
can
play
with
this
and
yeah
later
in
the
slides.
A
A
So
okay,
so
this
is
the
script
we
will
use
to
start
and
that's
the
part
where
I've
said,
which
I
have
a
little
bit
had
problems
with
that,
so
how
we
can
how
we
can
pass
variables
to
the
chain
code.
So
in
the
in
all
examples
I
have
seen
we
have
this
one.
So
we
have
the
invoke
command.
Then
we
have
here
the
c
the
c
option,
and
then
we
have
here
something
like
a
json
object,
but
on
the
first
position
we
have.
A
This
is
an
array,
as
you
can
see
here
in
any
way
and
then
the
first
position.
We
have
the
function.
So
the
first
position
is
the
function,
and
then
you
have
values.
So
when
it
comes
to
a
greater
or
a
larger
example,
where
you
have
more
properties
than
four
values,
then
you
will
have
a
large
or
a
huge
string
array
here
and
that's
not
really
comfortable.
A
A
But,
as
we
have
seen
here
yeah,
this
is
a
json
object
and
I
have
modified
this
so
in
a
way
that
we
can
use
only
one
parameter
here
so
and
we
will
use
a
json
object
and
we
pass
the
whole
json
json
object
to
the
chain
code
so
and
the
c
option.
According
to
the
documentation,
the
c
option
says
that
pass
a
message
for
the
chain
code
in
the
json
format.
A
So,
okay,
it's
a
json
format
and
that's
the
json
object
and
we
can
pass
this
json
object
to
the
chain
code
and
then
the
check
chain
count.
We
can
define
a
struct
to
catch
this
and
then,
in
the
next
step
the
structure
will
be
stored
into
the
blockchain
and
that's
that
works
really
really
good,
because
we
can
use
it
in
the
creation
process.
So
when
we
create
a
new
asset
and
also
when
we
update
an
existing
asset,
so
the
struct
here
and
the
import
mechanism
in
the
golem
is
very
comfortable
for
this.
A
So
it's
very
easy
to
pass
and
string
and
and
json
object
with
our
information
to
the
chain
code
and
in
the
in
the
chain
code.
We
use
destruct
design
element
to
build
a
new
object
to
for
the
creation
of
a
new
asset
and
also
for
the
update
from
from
from
this
asset.
But
we
only
want
to
update
one
property
for
for
this
asset.
A
A
So-
and
that
was
my
my
thinking
of
this-
and
I
have
improved
the
chain
code
to
this,
and
the
rest
is
the
same.
So
on
the
first
position,
we
have
the
function,
which
is
to
call
so
here
the
add
function
and
on
the
second
position
we
have
only
a
json
object.
So
we
don't
need
so
much
parameters
in
this
line
here
so
and
with
this
we
can
improve
this
okay
so
and
now
this
is
the
chain
code.
A
So
that's
that's
an
interesting
part
that,
because
we
want
we
have
an
asset
and
then
asset
has
different
states,
and
we
want
to
know
what
is
the
history
from
this
asset
and
then
we
want
to
query
the
the
the
asset
and
we
are
going
to
use
and
the
result
is
an
option,
an
objective
away
with
all
transactions
we
have
done
to
this
asset.
So
that's
that's
a
really
cool
thing
to
see
the
history
and
when
you
have
one
transaction
is.
The
next
question
is
how
you
can
query
this
transaction
and
yeah.
A
Okay-
I
have
missed
this
here,
but
we
will
see
this
later
on
the
chain
code,
and
the
data
model
here
is
that
we
have
the
data
item,
as
we
have
seen
in
the
last
example.
So
with
the
type
and
name
a
description
and
the
owner
and
the
owner
is
not
a
string.
So,
okay,
that's
that's
wrong,
so
the
type
is
not
the
string.
This
type
is
a
is
the
owner.
It's
this
owner
object
here,
and
the
owner
has
also
three
properties.
A
The
first
name,
the
last
name
and
the
department
and
new
is
here-
did
the
extension
here
to
the
type
so
the
the
bridge
to
the
json
object,
the
bridge
between
the
json
object
and
the
data
object.
Indigo
lang
in
the
struct
is
here
this
notation,
so
json
has
a
property,
it's
called
type
and
it's
written
lowercase,
also
the
name,
the
description
and
the
owner,
for
example,
so,
and
that
we
have
seen
in
the
last
session
and
with
this
extension,
omit
empty.
This
is
the
the
this
one
of
the
keys.
A
So
with
this
extension
we
can
say:
okay,
when
the
imported
json
don't
have
the
name
as
a
property,
then
the
data.
The
data
item
will
not
have
this
name
property
and
when
we
don't
use
this,
we
will
have
this
property
name,
but
it's
empty.
So
we
have
an
an
empty
property,
and
so
with
this
we
can
only
update,
for
example,
the
name
or
the
description
and
yeah
so,
okay.
So
now,
let's
switch
back
to
the
train
code.
A
So-
and
here
you
can
see
this
yeah,
we
see
this.
The
data
item
destruct
from
the
data
item
and
we'll
see
this
track
from
the
owner,
and
we
see
here
the
data
type
is
not
a
string.
It's
the
other
struct
distract
here,
and
this
is
the
key
yeah
omit
empty.
That
means
that
we
can
say:
okay
when
this
json
property
is
not
set,
the
data
item
will
not
have
it,
and
this
is
very
useful
when
it
comes
to
the
update
process.
So
then
we
don't
have
an
empty
property
in
the
database.
A
A
So
what
I
would
like
to
what
I
want
to
see
is
what
is
the
difference
between
the
key
and
the
transaction?
So
what
is
the
transaction
id
so
and
the
transaction
id
is
delivered
for
the
stop
interface
and
there's
a
method?
It's
called
get
txid
and
it
gives
us
the
transaction
id
and
the
key
we
have
seen
is
in
the
in
the
first
one.
A
A
So
no,
no,
no
so
this.
This
was
my
my
mistake.
So
in
my
last
in
my
last,
this
is
the
part
from
the
lessons
learned.
So
in
my
last
example,
I
have
created
a
unique
event,
a
unique
id,
and
that
was
the
problem
so
and
in
this
example
I
have
skipped
this
unique
id
and
from
the
chain
code,
and
I
have
created
this
unique
id
in
the
node.js
application
and
why
I
will
tell
you
later
in
this
lessons
learn.
A
A
So
we
have
to
convert
this
first
to
pipe
in
a
pi
day
way,
and
then
we
can
use
the
json
unmarshall
function
to
transfer
or
to
convert
this
height
away
to
the
item
which
we
have
created
here
so
and
then
we
have
an
item
and
then
the
next
step
is
the
same
as
we
have
seen.
So
when
we
have
this
item,
when
we
have
con
converted
this,
we
can
use
the
json
marshall
function
to
create
pipes
again,
and
this
data
item
json
as
paid,
will
then
be
stored
into
the
blockchain.
A
So
that's
that's
the
improvement
here.
So
we
say:
okay,
we
have
here
a
data
object,
json
object
and
we
convert
this
to
pipes
in
this.
In
this
variable
and
with
the
unmarginal
function
from
the
json
object,
we
can
create
this
struct
and
then
we
have
to
write
it
to
pipe
the
item
to
the
pythag
again
and
then
we
can
store
it
to
with
the
with
the
put
state
function
to
the
blockchain
and
with
our
key
so
and
the
key
we
have
to
remember.
A
This
is
one
of
the
problems
so
and
then
we
have
a
result
and
when
this
is
ready
and
we
have
a
success
and
not
an
error.
So
in
the
last
example,
the
key
or
only
a
success
message
was
delivered
back.
But
I
want
to
see
what
is
the
key
and
which
transaction
id
is
used.
And
for
this
I
have
created
a
new
function
is
a
get
key
as
pyth
function,
and
this
has
two
input
variables.
A
So
this
is
the
this
function,
so
get
key
as
bytes
so
and
the
return
value
is
a
python
so
and
we
can,
we
can
create
the
return
that
the
end.
The
final
result,
what
we
are
going
to
what
we
would
be
like
is
in
json
array,
it's
something
like
this,
so
we
want
the
json
not
to
chase
away
a
json
object
with
the
properties
key
and
transaction
id
so
and
that
we
have
seen
okay.
This
is
our
new
asset,
with
this
unique
id
with
the
unique
key
and
this
transaction
id
is
used
for
this.
A
For
this
asset
to
do
to
deliver
to
return
that
the
chain
code
can
return
this,
we
have
to
construct
a
pipes
buffer
like
this
and
then
that's
it's.
Basically,
as
you
can
see
here,
it's
a
json
object
as
well,
and
we
have
here
two
input
parameters
both
are
strings
and
in
this
way
we
can
construct
this
return
value.
A
The
update
function
is
now
completely
new,
so
here
it's
the
same.
So
we
for
this
update.
This
is
a
new
transaction,
so
we
get
the
transaction
id
and
our
input
parameters
are
also
the
same
so
to
update
the
key.
So
we
have
to
know
what
is
there?
What
is
the
key
for
this
for
this
asset,
so
our
unique
identifier
and
what
are
the
data
which
should
update
that?
A
Then
the
new
state
must
have
the
the
whole
asset.
So
the
the
new
state
from
an
asset
is,
is
the
asset
and
we
change
only
one
value.
So
I
think
I
don't
know
what
is
better
when
you
say:
okay,
you
send
the
whole
the
whole
asset
with
all
data
to
the
database.
Then
you,
you
don't
have
to
clear
the
the
the
state,
but
when
you
send
only
something
what
is
changed
in
this
asset,
then
you
can
do
this
in
this
way.
A
A
A
Now
and
then
we
marshal
the
data
with
the
item
and
that
the
interesting
part
here
is
that
when
we
we
are
going
to
do
this
in
this
way,
so
only
the
changed
part
from
the
from
the
json
from
the
centered
json
document
is
changed
in
the
whole
item.
So
when
we
have
item
a
struct
or
an
asset,
we
have
two
properties
with
a
name
and
the
first
name
and
the
last
name,
and
we
send
the
the
only
the
update
process
only
the
last
name.
A
So,
and
in
this
way
we
can
send,
we
can
reduce
the
traffic
to
the
chain
code
and
we
can
only
send
from
the
nodejs
application
these
datas,
which
are
changed,
and
the
chain
code
queries.
The
world
state
receives
the
whole
asset
and
in
the
next
step
it
changed
only
the
things,
the
properties
which
are
sent
to
the
chain
code
in
the
changed
properties.
A
A
So
yeah-
and
it's
basically
the
same
here
as
you
see
and
for
the
result
I
did
the
same
here
so
the
result
is
the
data
item
id
that's
the
key
from
from
our
asset
and
also
the
new
transaction
id
which
we
have
created
here
through
this
stuff.
So,
and
that
is
also
an
important
point
to
know
so
the
transaction
id
is
there
is
a
transaction
id
for
every
transaction
and
the
important
part
is
to
know
there
is
a
transactionally
for
every
valid
transaction
and
also
for
unvalid
transactions.
A
So
the
transaction
id
is
for
every
transaction,
unique
and
and
is
also
unique
over
the
blockchain
over
the
network.
So
and
that's
an
important
part.
In
my
last
example,
I
have
created
the
unique
identifier
id
into
the
chain
code,
and
this
leads
to
the
problem,
which
I
will
show
you
a
little
bit
later
so
and
that's
an
important
part
here.
A
Transaction
id
is
a
and
unique
id
for
for
every
transaction
and
it
doesn't
matter
if
this
transaction
is
valid
and
or
not
because
the
the
key
is
only
for
valid
transactions,
because
when
the
transaction
is
not
valid,
then
it
will.
Nothing
will
be
stored
in
the
blockchain
and
when
nothing
when
the
asset
is
not
stored
in
the
blockchain.
There
is
also
not
the
key
start
to
this
for
this
asset
so
and
that's
an
important
part.
So
in
the
fabric,
it's
like
an
invalid
transaction
is
also
stored
in
the
blockchain.
A
Okay,
so,
okay,
so
these
are
the
modifications
for
the
update
function,
okay,
so
decrease
by
id.
So
it's
pretty
the
same
as
we
have
seen
so
yeah.
This
is
also
the
selector.
This
is
for
the
couchdb
so
and
when
you
use
couchdb,
then
you
can
use
the
selector
query,
syntax,
what
couch
to
be
delivers,
and
these
are
the
rules
from
couchdb.
It
doesn't
matter
or
it
doesn't
belong
through
their
to
their
favorite
stuff.
So
but
it's
the
same
also
query
by
owner.
A
This
is
the
we
have,
and
here
this
is
a
wrong
question.
So,
yes,
we
can
clearly
sub
objects
and
because
and
that's
the
reason
why
we
are
going
to
use-
encourage
to
be
so.
We
can
also
use
a
level
db,
as
we
have
seen
last
week
and
but
level
db
is
much
more
secure.
So
it's
not
so
easy
to
to
change
the
world
state
because
I
think
for
level
to
be
there
is
no
unique
client
available.
A
So
the
client
must
be
built
around
the
application
and
it's
much
more
difficult
to
to
to
to
modify
to
tamper
the
world
state
than
encourage
to
be
because
in
culture
tv
you
have
the
ui
and
you
can
change
whatever
you
want,
but
you
have
more
create
functionality
and
you
can
query
every
object
in
the
in
your
json
object.
So
because
that's
a
nosql
database
and
and
then
you
know
it's
a
json-based,
no
secret
database
and
in
the
json-based
database
you
can
query
every
property
and
this
is
called
the
dot
in
this
dot,
syntax.
A
So
and
yeah.
You
can
query
everything
here
and
you
can
use
all
functions
and
operators
like
in
or
and
or
whatever
couchdb
provides
and
to
query
the
data.
So
this
is
the
way
here
and
that's
the
same
as
we
have
seen
last
last
week
and
their
talk.
Query
is
also
the
same.
So
that's
the
the
easiest
way
to
create
something.
A
So
we
have
here
a
query
string
and
we
pass
this
quiz
string
directly
to
the
query
function
here
and
with
this
you
can
give
the
node.js
application
a
lot
of
power
that
he
can
query
everything.
So
from
your
data,
a
model
and
yeah
from
from
your
assets.
So
but
this
is
depends
on
your
application.
So
but
I
think
not.
Every
function
which
we
have
seen
here
is
also
useful,
and
it
depends
really
on
the
use
case
and
you
have
to
choose
your
queries
and
your
methods
wisely.
A
You
can
determine
the
level
of
security
which
your
tools
you
are
chosen
to
use.
So
when
you
want
to
create
the
values
and
then
you
want
such
to
do
such
cool
queries
here,
then
you
have
to
use
couch
to
be,
but
you
have
to
note
that
in
this
way
you
reduce
the
level
of
security
and
you
have
to
protect
your
couchdb
database
more
then
you
have
to
protect
the
lavalier
beam
database.
So
that's
something
you
have
to
know.
A
Get
all
transaction
by
key,
so
that
means
that
we
want
all
transactions
for
an
asset
so,
and
we
will
see
that
I
will.
I
will
start
this
in
a
moment
and
then
we
we
are
going
to
see
when
we
update
an
asset.
So
a
new
asset
is
stored
in
the
world
state
and
we
can
see
this
also
in
the
in
encourage
db.
So
there
is
a
culture
b
property,
it's
called
under
under
underscore
ref,
and
with
this
we
see
the
diversions.
A
So
and
there's
that's
relative
easy
to
do
this,
so
the
go
sdk
the
chain
code,
the
go
chain
code
gives
you
a
method,
it's
called
get
history
for
key
and
you
have
only
to
pass
the
key.
So
that's
our
unique
identifier
and
that's
it
so
and
now
we
we
don't
query
only
the
word
state.
So
we
query
the
blockchain
in
this.
A
In
this
thing,
so
I
mean
I
mean
I'm
not
exactly
sure,
but
from
my
understanding
in
this
for
this
we
will
not
create
a
world
state,
so
instead
we
will
create
the
the
ledger
directly,
because
we
we
want
all
transactions
and
all
states
for
this
particular
key
and
yeah.
So
and
then
you
have
this
recycled
iterator
and
that's
it
basically.
So
then
you
can
construct
here,
your
return
values,
so
this
is
also
in
the
marvel
example
written.
A
So
this
is
so,
as
I
have
mentioned
several
times,
so
the
the
fab
examples
has
a
lot
of
good
examples
to
learn
and
to
see
how
you
can
do
this
yeah,
but
I
think
you
can
modify
this
and
when
you
an
experienced,
go
developer
or
an
experienced
nodejs
developer,
then
you
can
modify
this
in
the
in
some
ways
so
to
to
improve
this
this
time
of
doing
so
yeah.
But
these
are.
This
function
is
also
from
the
marble
example.
So
it's
but
the
key
is
really
simple.
A
So
you
have
this
one
here
and
then
you
have
to
construct
the
buffer,
as
we
have
seen
it
with
the
transaction
id.
So
it's
in
the
response
here
and
then
the
value
is
also
the
in
that
you
see
here.
This
quote
so
this
quotes
is
from
my
testing.
So
when
we
use
this
in
the
basic
chain
code,
this
example
underscore
0
2
chain
code,
where
we
can
store
only
the
value
a
and
b,
and
we
have
the
the
amount
of
values
from
a
to
b.
A
Then
we
will
have
as
a
return
here,
not
a
json
object,
so
we
will
have
a
maybe
a
key,
a
string,
and
when
this
string
a
is
with
with
a
space,
then
we
will
receive
an
error
here
and
to
get
around
this.
I
have.
I
have
wrapped
this
in
this
quote,
so
so
that's
the
reason
why,
for
this
test
I
have
here
this
quotes,
but
for
the
json
object,
we
don't
need
this
and
yeah
timestamp
and
that
it's
deleted.
A
So
that
was
also
a
question
from
the
channel
from
the
slack
channel
last
week.
So
immutability
is
one
key
for
a
blockchain,
so
in
the
blockchain
you
can't
delete
the
history
of
a
of
a
of
an
asset.
So
when
we
delete
this,
so
only
the
state
is
deleted
and
not.
We
cannot
delete
the
history
for
for
for
an
asset.
A
So
that's
something
you
have
to
know
and
that's
also
when
you
come
from
a
developer
side
and
yeah,
so
we
have
to
think
in
a
different
way
and
so
that's
a
key
functionality
from
a
blockchain.
So
we
can
mark
an
asset
as
deleted,
but
we
cannot
delete
the
whole
information
which
is
stored
into
the
blockchain
and
yeah
okay.
So,
okay,
that
was
a
short
overview
already
over
the
chain
code.
So
this
the
chain
code
is
into
there
into
my
my
github.
A
A
So
maybe
some
one
of
you
want
to
extend
this
so
the
delete
function,
so
the
delete
functionality
is
left
here,
so
we
have
to
bring
in
here
a
new
function
to
delete
an
asset.
So
maybe
someone
of
you
want
to
want
to
try
this?
Then
he
can
copy
this
chain
code
and
then
he
can
modify
his
chain
code
by
his
own
and
he
tried
and
he
can
try
to
extend
it
to
delete
one
asset.
A
A
So
that's
from
the
theoretical
part.
So
now,
let's
move
so
let
me
see
what
I
have
on
the
slides.
So
before
I
come
to
this
so
okay,
this
we
can.
We
can
look
a
little
bit
in
this,
so
the
difference
between
key
and
transaction
id.
So
in
this
in
this
short
image
here
we
can
see
the
different.
I
have
tried
to
to
explain
this
here
so
when
we
have
an
asset,
so
the
key
point
of
an
asset
is
that
we
have
a
key
and
a
value.
A
So
the
key
is
a
string
yeah,
a
unique,
unique
unix
string
and
the
value
are
the
types
we
have
seen
so
and
that
was
that
what
will
be
stored
into
the
blockchain
so
but
we
can
have
a
huge
json
object.
We
convert
this
to
bytes
and
then
we
have
only
here
the
key
and
the
bytes,
so
that's
an
asset
so
and
every
asset
yeah
is
displayed
in
a
state
and
the
state
is
the
last
version.
The
world
state
is
the
last
version
of
this
asset
and
to
create
an
asset
or
to
change
an
asset.
A
We
have
a
transaction
so
and
this
transaction
has
an
id
and
has
a
lot
of
informations
in
and
when
we
make
this
transaction,
we
have
an
id,
and
this
id
stands
for
exactly
this
state
and
when
we
update
this
asset
we
have
another
id
and
this
transaction
stands
for
exactly
the
second
state
and
so
on.
So
the
transaction
ids
are
always
unique
within
the
scope
of
the
channel.
I
have
written
this
here
so
and
what
I
have
seen.
I
will
that's
something
I
would
like
to
show
you
in
a
moment.
A
So
that's
the
read
write
set.
So
when
you
look
to
the
documentation
and
then
you
read
it,
then
you
will
see
the
the
term
reader
read
write
set.
So
that's
a
part
from
the
administrator
course.
I
think
so
that
we
can
see
what
is
the
read
write
set,
and
this
is
the
transaction
so
and
when
we
see
how
that's
a
huge
json
object
to
query
the
the
final
transaction
and
it's
really
interesting
to
see
which
informations
are
in
this
transaction.
A
So
that's
that's
really
interesting
so,
but
the
transaction
id
is
unique,
identifies
the
the
uniquely
the
transaction
on
the
channel.
So
that's
important
to
know:
that's
only
on
the
channel,
so
we
have
a
channel.
We
have
a
chaincode
installed
on
this
channel
and
this
channel.
The
transactionality
is
unique
to
this
channel
and
the
same
for
the
key.
So
the
key
is
also
unique
in
the
scope
of
this
channel.
A
A
A
So
we,
the
network
is
created,
the
crypto
material
is
created,
the
channels
are
created
and
joined
to
the
peers
and
everything.
What
you
need
that
this
network
is
running,
we'll,
create
it
through
this
script
and
but
no
chain
code
is
installed
so
and
then
we
have
to
install
the
chain
code
by
ourself
with
these
commands
here.
So
we
have
to
install
it
and
we
have
to
instantiate
it
on
one
piece,
and
this
takes
one.
A
A
A
A
We
see
our
peers,
we
see
the
certified
authority
as
a
favorite
ca
and
you
see
the
order-
and
we
see
also
culturally
be
here,
but
we
see
only
one
chain
code
container
and
that's
it's
also
important
finding
out
to
know
that
the
chain
code
is
is
executed
in
a
single
container,
and
this
is
called
the
chain
code
container,
and
you
see
this
is
here
only
for
pier
0
or
1
the
chain
code
container,
and
so
that's
it
and
the
next
thing.
What
we're
going
to
do
is
we'll
be.
A
We
have
to
use
this
so
for
this
we
can
use
our
train
nodejs
application.
I
have
modified.
I
have
rewritten
this
application
in
a
way
that
we
can
use
this
chain
code
functions,
but
I
think
it's
too
too
time
consuming
to
to
go
through
all
the
steps.
So
I
will
show
you
only
the
the
the
key
parts
from
this
and
if
you
want
to
know
how
you
can
do
this,
then
you
can
look
at
the
github
repo
and
I
think
I
have
comments
on
every
line.
A
So
you
can
see
how
this
works
and
you
can
easily
make
your
own
application
based
on
something
like
this.
So
so,
but
now
we
have
a
running
fabric
system,
and
now
we
want
to
use
a
client
application
and
nodejs
application
to
query
to
create
an
asset,
to
update
an
asset,
to
update
an
asset
again
and
then
we
want
to
see
okay,
what
are
the
transactions
from
this
essay
asset
and
then
we
are
going
to
create
one
single
transaction
from
the
past.
A
A
A
A
So
he
is
decent
identity.
So
we
will
we
clear
this
so
now
and
how
we
can
get
this
identity.
So
this
this
is
a
part
in
which
we
have
seen
two
sessions
in
the
path
so,
where
I
have
explained
how
you
can
connect
to
this
network,
how
you
can
use
the
connection
profile
for
this
and
how
you
can
register-
or
you
can
add
the
user
to
the
wallet
so
it
is.
A
I
would
like
to
skip
now,
so
I
only
want
to
use
this
so
and
we
use
the
same
script
as
we
have
seen
in
the
last
in
the
past.
So
and
this
is
the
script
add
to
wallet.
So
this
is
also
you
find
the
script
in
his
original
way
or
also
in
the
in
the
fair
examples,
and
we
do
this
for
the
user.
One
yeah
part
one
user,
so
this
this
for
in
the
in
the
setup
process.
A
From
this
example,
there
are
two
users
automatically
created
user
one
and
an
admin
user
for
every
organization
so
and
we
use
the
user
one
to
use
this
in
our
node.js
application,
and
there
are
two
ways
where
we
can
get
an
identity
and
valid
identity
for
this
nodules
application.
The
first
thing
is
that
we
use
the
edge
to
wallet
method,
so
that
means
that
we
have
already
user
credentials.
We
have
a
registered
users,
the
user
is
enrolled
and
that's
what
did
what?
A
What
happened
when
you
use
the
build
your
first
network
script
and
the
second
one
is
that
you
enroll
in
admin
from
the
favorite
ca,
and
then
you
will
register
with
the
script,
your
own
user
against
their
favorite
cr,
and
you
can
then
register
and
then
enroll
the
user
for
the
node.js
application.
So
this
also
depends
on
your
business.
A
Needs-
and
there
are
two
ways
to
do
this-
the
the
shorter
way
for
now
is
the
first
way,
so
we
have
an
a
user
user
one
and
to-
and
we
have
also
the
crypto
materials
from
this
user
and
the
only
thing
what
we
need
here
now
is
the
unique,
the
private
key
from
this
user.
So-
and
this
is
an
important
part
to
know
every
time
you
start
your
build
your
first
network
example,
then
the
crypto
material
is
every
time
is
new
generated
so
that
the
names
are
the
same
here.
A
So
I
have
here
a
counting
object
and
the
names
are
here
hard
coded
and
yeah.
The
names
are
always
the
same.
The
paths
are
the
same,
but
the
private
key
here
is
changing
every
time.
So
we
have
to
now
show
what
is
the
private
key
for
this
user
and
copy
and
paste
this
to
the
to
this
position
here
and
then
we
can
use
the
script
to
enroll,
the
user.
So
and
that's
we
will
look.
A
A
We
have
the
one
organization
you
have
on
this
level
or
organization
two
or
three
or
whatever,
and
then
you
have
a
folder
users,
and
then
these
users,
you
have
user
one
user
tool
and
the
admin
user,
and
then
you
will
have
the
msp
folder.
So
that's
the
membership
service
provider
folder.
So
that's
the
important
part
for
us
and
from
this
part
we
need
the
key
store.
A
So
and
this
key
we
have
to
fill
in
here
so
and
with
this
we
can
call
a
node
edge
to
wallet
and
when
he
is
done,
we
can
look
at
three
wallet
and
you
see
here
we
have
now
the
user
one.
We
have
the
private,
the
public
key
and
here
the
meta
informations,
which
we
have
also
seen
in
the
sessions
before
so
now.
We
have
a
valid
identity,
and
with
this
in
mind,
we
can
start
our
application,
and
for
this
I
use
a
node
mode.
A
Does
this
job
for
you
and
that's
not
for
production,
so
that's
only
for
development
and
when
we
start
this
and
we
have
connection
to
the
network
very
ap
services
listening
to
3000.
So
now
we
are
a
running
node.js
application
here
and
we
have
also
a
connection
to
the
fabric
network,
so
this
is
basically
done
through
the
connection
script
which
we
have
seen
in
the
last
sessions.
So
I
have
changed
here.
A
A
A
The
blockchain
so
and
this
could
be
done
with
the
npm
test.
It's
also
the
same,
and
now
look
at
this
docker
stats.
You
see
here
new
chain
code
containers
are
created
so,
but
for
the
first
time
it
takes
some
time
to
create
and
build
the
chain
code
container
for
every
tier
and
because
we
have
said
in
our
endorsement
policy
that
we
has
the
end
option
so
one
for
every
asset.
We
need
a
confirmed
transaction
on
from
one
peer
in
the
organization
one
and
for
one
p,
in
the
organization
two
so
and
now.
A
We
will
have
here
two
more
chain
code
containers
yeah.
We
have
here
depth,
pier
0,
that's
from
part
1
and
we
have
def
ps,
zero
from
arc
two,
and
we
have
here
the
fp1
from
r1
so
and
now.
Okay,
this
error
message
is
okay,
because
it
was
too
long.
It
was
a
time
limit,
but
the
transaction
is
valid,
so
we
have
here
our
key
our
asset
key,
and
here
we
have
the
transaction
id
so
and
when
we
look
at
this
ad,
so
here
you
can
see
this,
it's
very
easy.
A
So
here
I
have
changed.
I
have
skipped
the
unique
id
from
the
train
code
and
I
have
created
here
a
unique
id
from
from
nodejs
from
the
nodule
side,
and
I
pass
this
here.
The
key
and
the
value
and
the
value
is
data
object.
As
you
see
here,
yeah
json
object
and
we
have
to
string
a
file
with
json
and
then
we
can
send
it
to
the
transaction,
the
contracts
submit
transaction
function
and
and
then
we
can
print
out
the
result.
So
for
this
I
need
the
unit.
A
A
So
we
need
now
this
transaction,
this
key
the
unique
key.
So
we
skip
the
add
method
and
we
use
the
update
network
fill
this
in
here.
So
and
yeah
that's
another
text,
so
we
have
the
name.
We
have
a
description
yeah,
but
we
don't
change
the
owner.
We
don't
change
the
type
here
and
we
saw
the
npm
test
again.
A
A
So
and
then
so,
these
are
the
queries,
I
think
that's
pretty
straight
forward,
so
we
can
create
by
id.
You
have
to
fill
in
here
the
key
yeah,
the
the
owner,
so
you
can
create
the
owner,
so
you
can
write
here
the
owner
as
a
string,
so
you
can
have
here
the
talk,
query
where
you
can
pass
the
selector.
Also
we
use
index
element
here,
as
we
have
seen
last
time.
A
So
the
last
two
things
we
are
going
to
see
here
is
is
now
this
one,
so
we
are
going
to
try
the
get
all
transaction
by
id
function.
So,
and
you
see
here,
I
have
to
recite
a
little
bit
modified
that
we
see
this
a
little
bit
clearer.
So
let
me
now
start
the
test
function
and
you
see
here
we
have
two
transactions
for
both
states
and
here,
but
so
maybe
it's
a
problem
from
the
scrolling
and
then
we
say:
okay,
that's
the
first
thing.
We
want
this
one.
A
So
and
then
you
call
this
test,
and
now
you
have
the
now
you
have
queried
the
state
or
the
the
the
read
write
set:
it's
not
the
state.
So
technically,
I
think
the
the
right
term
is
the
read
write
set
from
this
transaction,
and
but
this
could
be
wrong,
so
this
could
also
be
not
valid
transaction
and
I
will
show
you
in
the
get
transaction
function
so
how
you
can
query
this.
This
is
a
little
bit
different
to
to
the
other
stuff
so,
but
in
every
in
every
query.
A
A
A
That's
the
important
part
is
that
we
pass
this
to
the
endpoint
to
the
query
endpoint,
so
we
have
to
pass
the
gateway,
yeah
and
the
config
so
because
this
config
object
is
only
for
the
channel
name
so
yeah,
but
we
have
to
pass
the
gateway
to
this.
This
api
endpoint
and
in
this
api
endpoint
we
can
in
this
gateway
we
can
create
the
client.
So
we
can,
we
can
call
a
method,
get
client,
and
now
we
have
the
corresponding
client
to
this
gateway
and
in
this
client
we
have
a
method.
A
A
So
this
information,
the
key-
I
said
this
is
the
read
write
set.
I
call
I
think
it's
the
read,
write
set:
it's
not
an
an
an
an
asset.
It's
not
a
state,
so
this
is
the
wheat
white
set
which
is
centered
to
the
blockchain
and
when
it
when,
if
it's
valid
it's
exactly
the
same,
like
the
state
we
have,
we
have
seen
in
the
in
the
country,
for
example.
A
So
it's
really
interesting
to
see
what
is
really
into
the
read
write
set
and
there
that's
really
a
huge
aspect
here.
So,
but
when
you
have
this,
then
you
can
it's
a
json
object.
Then
you
have
to
pass
this
json
object.
Object
and
then
you
can
here
construct
the
result
object
here.
The
key
is
the
transaction
id
and
with
right
set
is
here
there
yeah?
A
A
So
my
problem
was
with
this
I
received
the
following:
error:
failed
to
submit
transaction
and
code
endorsement
policy
failure.
So
what
does
this
mean?
So
I
have
created
and
I've
googled
and
created
this,
and
I
have
I
haven't-
found
a
good
solution
for
this,
but
the
problem
here.
The
lesson
I
have
learned
is
not
that
I
have.
It
was
a
problem
in
the
indigo
nego
code
or
any
notions
code
so
and
also
not
in
in
the
setup
from
there
from
the
from
the
test
network.
A
So
everything
worked,
but
a
completely
different
thing
happened
so
and
that's
a
part
which
I
have
not
really
recognized
in
the
moment
where
I've
designed
this
train
code
and
the
reason
for
this
is
in
my
last
presentation.
Last
week
I
have
used
a
I've,
created
the
unique
identifier
id
into
the
train
code
and
have
also
to
demonstrate
how
we
can
query
the
timestamp.
A
I
have
created
a
timestamp
into
the
train
code
so
and
I
have
stored
this
into
the
blockchain
and
I
used
the
or
operator
and
it
works
so
because
only
one
peer
has
to
successfully
endorse
this
transaction,
and
when
I
do,
I
try
this
with
the
ant
option,
so
that
also
this
second
organization
has
to
endorse
this
policy
in
the
census.
This
both
organization
must
come
to
the
same
result.
Then
it
can't
be
happened
because
when
we
create
the
unique
id
in
the
train
code
for
the
pr1
you
can
see
here.
A
This
is
the
simplified
process,
so
the
sdk
here
the
node.js
sdk,
sends
the
the
the
call
to
them
to
the
peer
knowledge
to
the
chain
code.
The
chain
code
is
executed
and
then,
in
the
chain
code
a
new
unique
id
is
created.
So
the
name
is
is,
is
the
key,
so
unique
id?
So
that's
an
unique
id
and
it
delivers
back
a
hash
yeah
from
the
hashed
value
and
the
same
happened
on
peer
null
ii
yeah.
A
These
are
completely
different
things,
so
the
train
code
is
the
same,
but
the
chain
code
does
the
same,
so
it
created
a
new,
a
new,
unique
id
so
and
then
we
have
oops,
and
then
we
have
a
response
here
in
hash,
but
these
are
completely
different
hashes
and
this
leads
to
the
endorsement
policy
failure,
because
I
have
tampered
myself
with
a
general
something
like
this.
So
it's
called
it's.
I
it's
it's
completely
stupid.
But
what
is
this?
What
is
the
lesson?
A
The
lesson
is
that
I
my
background
is
a
I'm,
a
background,
developer
and
a
backhand
developer,
and
I
have
a
special
kind
of
thinking
how
an
application
has
to
be
developed.
So
when
you
send
some
data
to
the
server,
then
the
server
has
to
create
a
log
id.
Your
server
has
to
create
a
time
stamp
and
so
on,
and
that
was
that
is
the
thinking.
But
when
you
create
a
blockchain
application,
this
you
cannot
create
in
this.
A
I
think
so.
Then,
when
you
change
only
one
pipe,
you
will
receive
a
completely
different
hash
value
from
this.
So
that's
the
sense
from
a
hash,
so
the
the
hash
value
will
be
completely
different
when
you
change
only
one
pipe,
and
that
was
my
learning
in
this
week.
So
I
have
to
think
as
a
blockchain
developer
and
when
you
build
such
applications
like
this,
then
you
have
to
know
exactly
what
you
are
doing
and
how
this
works
in
the
whole
way
together.
A
A
Okay.
So
what
we
have
here
so
yeah,
the
last
thing
only
so
is
here
you
can
have.
I
have
two
three
references
for
you.
This
is
the
the
the
train
could
go
shim
documentation
from
the
go
code.
So
that's
really
good
to
look
through
this
that
you
see
which
functions
you
can
call
then
the
same
here
from
the
node.js
and
here
on
my
github
repo
is
the
the
repo
for
this
examples.
So
you
can
find
here
yeah,
that's
funny
yeah.
So
that's
a
low
dish,
vulnerability.
A
So,
but
I
don't
know-
but
here
you
can
see,
this
is
the
supporting
material.
So
this
is
the
the
way
where
you
can
create
the
space
network,
and
here
you
have
this
this
script
and
there
was
a
stop
script.
So
you
can.
If
you
stop
this,
and
here
you
have
the
the
nodejs
application-
and
here
you
have
the
chain
code.
So
this
is
the
chain
code,
and
here
you
have
also
the
way
so
the
last
sessions
we
have
seen
a
little
bit
more,
the
chain
called
docker
dev
mode
environment.
A
So
this
is
also
a
step-by-step
guide
where
you
can
start
these
three
panels
which
I
have
seen
here.
I
use
this
terminal
multiplexer
for
this
and
yeah.
So
that's
for
the
development
of
this
chain
code,
so
you
can
test
it
and
then
it's
also
for
the
for
the
node.js
developer.
When
you
come
from
your
web
development,
it's
really
important
that
you
can
test
your
chain
code
with
the
cli
container.
So
that's
the
first
line
of
test
which
you
can
do
to
see
how
this
works
so
and
in
this
docker
dev
mode.
A
A
So
that's
only
one
index
now
because
I
have
skipped
the
time
so
the
time
property
so
that
that's
also
a
part
which
we
can
now
improve
that
we
can
index
sort
by
time
when
you
use
something
sort
in
couchdb.
You
meet
an
index
for
this,
and
so
this,
but
this
is
also
apart
from
from
the
last
session,
so
yeah
and
yeah.