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manual abstract
Data
Types
and
Databases
There
are
sev
eral
dierences
b et
w
een
the
data
t
yp es
for
databases
and
those
for
T
ransact.
The
main
dierence
is
that
databases
require
all
data
items
to
b e
dened
as
whole
w
ords
on
w
ord
(16-bit)
b oundaries.
T
o
maintain
consistency
,
y
ou
can
dene
a
data
item
in
T
ransact
with
an
o dd
n
um
b er
of
b
ytes,
but
sp ecify
that
the
data
item
b e
stored
in
whole
w
ords.
F
or
example,
y
ou
can
dene
a
data
item
in
T
ransact
as
9(5,0,6)
to
sp ecify
5
digits,
stored
as
6
b
ytes.
This
example
illustrates
the
second
dierence
b et
w
een
databases
and
T
ransact
data
t
yp es.
Databases
do
not
ha
v
e
a
n
umeric
ASCI I
string
data
t
yp e.
This
dierence
do es
not
cause
problems.
T
ransact
automatically
con
v
erts
an
y
n
umeric
ASCI I
(data
t
yp e
9)
data
items
to
alphan
umerics
(data
t
yp e
X)
b efore
use.
When
data
is
transferred
in
to
a
T
ransact
t
yp e
9
data
item,
T
ransact
c
hec
ks
to
make
sure
the
data
is
n
umeric.
Data
Types
and
Data
Dictionaries
Y
ou
can
create
a
data
dictionary
in
whic
h
y
ou
dene
the
data
items,
databases,
forms
les,
MPE
les,
and
KSAM
les
to
b e
used
in
T
ransact
programs.
The
use
of
a
data
dictionary
as
a
cen
tral
lo
cation
for
data
denitions
and
attributes
allo
ws
y
ou
to
c
hange
existing
denitions
and
attributes
easily
and
dynamically
.
The
data
dictionary
do es
not
supply
the
data
itself,
whic
h
m
ust
come
from
MPE
or
KSAM
les,
databases,
forms
les,
or
the
user.
There
is
an
exact
corresp ondence
b et
w
een
the
data
item
denitions
a
v
ailable
with
T
ransact
and
either
Dictionary/V
or
System
Dictionary
.
Th
us,
when
a
T
ransact
program
uses
a
data
item
dened
in
a
data
dictionary
,
it
is
as
if
it
w
ere
dened
in
the
program's
DEFINE(ITEM)
statement.
All
data
item
attributes
can
b e
resolved
from
the
data
dictionary
when
T
ransact
compiles
the
program.
If
Dictionary/V
items
are
to
b e
resolved
at
T
ransact/V
run
time,
all
attributes
except
for
heading
or
en
try
text,
edit
masks,
and
sub-items,
can
b e
resolved.
T
ransact
allo ws
y
ou
to
use
either
Dictionary/V
or
System
Dictionary
or
b oth
in
one
program.
If
y
ou
do
not
sp ecify
,
T
ransact
assumes
Dictionary/V,
b
y
default.
T
o
use
System
Dictionary
,
y
ou
m
ust
include
sp ecial
compiler
commands
in
y
our
source
le.
These
commands
are
describ ed
in
Chapter
9.
When
T
ransact
takes
data
item
denitions
from
System
Dictionary
,
only
attributes
dened
at
the
data
item
lev
el
can
b e
accessed.
An
y
attributes
dened
at
the
relationship
lev
els
are
inaccessible,
since
T
ransact
commands
can
include
only
the
item
name
and
pro
vide
no
w
a
y
for
transmitting
con
text
information.
Therefore,
if
an
item
is
to
ha
v
e
dieren
t
attributes
in
dieren
t
con
texts,
System
Dictionary
m
ust
con
tain
a
separate
item
name
and
denition
for
eac
h
dieren
t
set
of
attributes.
If
the
data
in
System
Dictionary
is
structured
so
as
to
supp ort
Hewlett-Pac
k
ard's
information
managemen
t
softw
are
(suc
h
as
BR
W),
it
is
recommended
that
dual
dictionaries
(or
domains)
b e
maintained|one
to
supp ort
Information
Management
applications
and
the
other
to
supp ort
T
ransact
applications.
In
the
System
Dictionary
that
supp orts
T
ransact
applications,
data
items
can
then
b e
redened
as
often
as
necessary
.
When
dening
data
items
whic
h
are
extracted
from
System
Dictionary
or
Dictionary/V
for
use
in
a
T
ransact
application,
y
ou
should
note
that
T
ransact
only
supp orts
data
item
names
that
are
up
to
16
c
haracters
long.
If
a
data
dictionary
is
b eing
used,
the
T
ransact
compiler
lo
oks
for
an
y
undened
data
items
in
the
appropriate
data
dictionary
.
If
it
cannot
nd
the
data
items
in
the
data
dictionary
,
it
issues
a
w
arning
message.
October
1996
Data
Items
3-9
...Other models in this manual:
Software - MPE/iX 6.5 Operating System (915.38 kb)
Software - MPE/iX 7.0 Operating System (915.38 kb)
Software - MPE/iX 7.5 Operating System (915.38 kb)