Data Area:
Overview:
This module enables the student to
understand the concept of Data Area.
Outline:
Topics covered,
·
Create
Data Area.
·
Change
Data Area
·
Delete
Data Area.
·
Retrieve
Data Area
·
Data
area opcodes.
Objective:
By the end of this module, the student should be
able to:
- Create a Data-Area
- Change Data Area
- Delete Data Area.
- Retrieve Data Area
- Understand the Data Area opcodes.
Definition
Data Area is an object used for passing
information between programs within a job and between jobs.
Two programs can not simultaneously use the
same data area for update. If the program calls another program that uses the
same data area with UNLCK opcode before the other program is called.
Steps to create data Area .
- Type CRTDTAARA on Command prompt.
- Press F4
- The screen shown below will get displayed.
Create Data Area
(CRTDTAARA)
Type choices, press Enter.
Data area
. . . . . . . . . . . DTA1 Name
Library
. . . . . . . . . . . PB01U01O Name, *CURLIB
Type . . . . . . . . . . . . . .*CHAR *DEC,*CHAR,*LGL, *DDM
Length:
Length . . . . . . . . . . . . 21 1-2000
Decimal positions . . . . . . 0-9
Initial value
. . . . . . . . . 'DUKESTAR
TECHNOLOGIES'
Text 'description' . . . . . . . *BLANK
Bottom
F3=Exit
F4=Prompt F5=Refresh F10=Additional parameters F12=Cancel
F13=How to use this display F24=More keys
4. Press Enter & Data
Area will get created with initial
value
‘Dukestar
Technologies’
- Type CHGDTAARA on Command prompt.
- Press F4
- The screen shown below will get displayed.
Change Data Area
(CHGDTAARA)
Type choices, press Enter.
Data area specification:
Data area
. . . . . . . . . .DTA1 Name, *LDA, *GDA, *PDA
Library
. . . . . . . . . PBO1U01O Name, *LIBL,
*CURLIB
Substring
specifications:
Substring starting position .
1 1-2000, *ALL
Substring length . . . . . . . 15 1-2000
New value
. . . . . . . . . . . 'DATA
AREA '
Bottom
F3=Exit
F4=Prompt F5=Refresh F12=Cancel
F13=How to use this display
F24=More keys
4. Press Enter & Data Area will get changed
Delete
Data Area.
- Type DLTDTAARA on Command prompt.
- Press F4
- The screen shown below will get displayed.
Delete Data Area
(DLTDTAARA)
Type choices, press Enter.
Data area
. . . . . . . . . . . DTA1 Name, generic*
Library . . . . . . . . . .
. PB01U01O Name, *LIBL, *CURLIB...
Bottom
F3=Exit
F4=Prompt F5=Refresh F12=Cancel
F13=How to use this display
F24=More keys
4. Press Enter to Delete the Data Area
Retrieve Data Area
To retrieve
the value of data area we have to write a CL program
- Create a CL program CL2
Columns
. . . : 1 71
Edit
PB01U01S/MYCLP
SEU==>
CL2
FMT **
...+... 1 ...+... 2 ...+... 3 ...+... 4 ...+... 5 .
************* Beginning of data ********************
0001.00 PGM
0002.00 DCL VAR(&VAR1) TYPE(*CHAR) LEN(10)
0003.00 RTVDTAARA
DTAARA(PB01U01O/ DTA1
(1 10))+
RTNVAR(&VAR1)
0004.00 SNDPGMMSG MSG(&VAR1)
0005.00 ENDPGM
********** End of data ************************
F3=Exit
F4=Prompt F5=Refresh F9=Retrieve
F10=Cursor F11=Toggle
F16=Repeat find F17=Repeat change F24=More keys
(C)
COPYRIGHT IBM CORP. 1981, 2002.
- Retrieve Data Area (RTVDTAARA) is used to retrieve values from a data area
Retrieve Data Area
(RTVDTAARA)
Type choices, press Enter.
Label .
. . . . . . . . . . . .
Data area specification:
Data area
. . . . . . . . . . > DTA1
Name, *LDA, *GDA, *PDA
Library
. . . . . . . . . . >
PB01U01O Name, *LIBL, *CURLIB
Substring specifications:
Substring starting position . > 1 1-2000, *ALL
Substring length . . . . . . . > 10 1-2000
CL variable for returned value > &VAR1 Character value
Comment
. . . . . . . . . . . .
Bottom
F3=Exit
F4=Prompt F5=Refresh F12=Cancel
F13=How to use this display
F24=More keys
In this CL
program value from Data Area is Retrieve and store the value in variable var1.
and then this value is passed to the program message queue.
Data
area Opcodes
Following are the data area opcodes.
IN, OUT and
UNLCK. We will see all opcodes one by one.
IN
(Retrieve Data area)
IN opcodes retrieves a data area specified
in factor 2 of calculation specification. This allows you to control the
locking or unlocking of a data area.
Note:
If you want to use data area opcodes IN, OUT or ULCK then you must define this
data area with DEFN opcode using *NAMVAR in factor 1 and name of data area in
result field.
Following is the specification format for
the IN opcode.
|
Factor1
|
OPERATION
|
FACTOR
2
|
RESULT
|
HI LO EQ
|
|
*LOCK
|
IN
|
Data area name or *NAMVAR
|
b
|
b ER b
|
Factor1 entry is optional. It can be blank
or contain the reserve word *LOCK. Factor1
must be blank if factor 2 is name of local data area (*LDA) or program
initialization parameters (PIP) data area. *LOCK in factor 1 indicates that
the data area cannot be updated or locked by another program until (i) an UNLCK
operation is processed, (ii) an OUT operation with no factor1 entry is
processed or (iii) the RPG/400 program implicitly unlocks the data area when
the program ends.
Factor 2 entry contains the name of data
area or the reserve word *NAMVAR. Opcode IN with *NAMVAR retrieves all the data
area defined in the program (See program PGMDTA3)
You can specify resulting indicator in
positions 56 and 57 (LO entry). This indicator will set on if an error has
occurred during the operation.
OUT
(Update Data area)
The out opcode update the data area
specified in factor2.
|
Factor1
|
OPERATION
|
FACTOR
2
|
RESULT
|
HI LO EQ
|
|
*LOCK
|
OUT
|
Data area name or *NAMVAR
|
b
|
b ER b
|
Factor 1 entry is optional. It can be blank
or contain the reserve word *LOCK. Factor 1 must be blank if factor 2 is name
of local data area (*LDA) or program initialization parameters (PIP) data area.
*LOCK in factor 1 indicates that data area remains locked after it is updated.
When factor1 is blank, the data area is unlocked after it is updated.
Factor 2 entry contains the name of data
area to be updated or the reserve word *NAMVAR. Opcode OUT with *NAMVAR updates
all the data area defined in the program. You can specify resulting indicator
in positions 56 and 57 (LO entry). This indicator will set on if an error has
occurred during the operation.
UNLCK
(Unlock a Data Area or Release a Record)
The UNLCK operation is used for 2 purpose.
The UNLCK operation unlocks data areas and
allows the most recently locked record to be unlocked for an update disk file.
The following is the specification format
for the IN opcode.
|
Factor1
|
OPERATION
|
FACTOR
2
|
RESULT
|
HI LO EQ
|
|
b
|
UNLCK
|
Data area name or File Name
|
b
|
b ER b
|
Factor2 must contain the name of the data
area to be unlocked, the name of an update disk file, or the reserve word
*NAMVAR. When *NAMVAR is specified in
factor2 all data areas in the program which are locked, will be unlocked.
Factor 2 must not refer to the local data
area of the program initialization parameter (PIP) data area. If factor 2
contains file name then that file must be defined as an update disk file.
You can specify resulting indicator in
positions 56 and 57 (LO entry). This indicator will set on if an error has
occurred during the operation.
RPG Program for IN opcode
Columns
. . . : 1 71
Edit
PB01U01S/MYRPG
SEU==>
DTARPG1
FMT *
..... *. 1 ...+... 2 ...+... 3 ...+... 4 ...+... 5 ...+... 6 ...+...
7
************* Beginning of data ***********************
0000.01 C*Define Data Area with *NAMVAR
0001.00 C *NAMVAR DEFN DTA1 21
0001.02 C*Retrieve Data Area with IN
0002.00 C *LOCK IN
DTA1
0003.00 C MOVE 'Pune' FLD1
10
0004.00 C MOVE *BLANKS FLD2
50
0004.02 C*Concatenate DTA1 value with FLD1 value
and store it in C* FLD2
0005.00 C DTA1 CAT
FLD1 FLD2
0006.00 C FLD2 DSPLY
0006.02 C*Unlock Data Area
0007.00 C UNLCKDTA1
0008.00 C SETON LR
*************** End of data *******************************
F3=Exit
F4=Prompt F5=Refresh F9=Retrieve
F10=Cursor F11=Toggle
F16=Repeat find F17=Repeat change F24=More keys
RPG Program for OUT
Opcode
Columns . . . : 1
71 Edit PB01U01S/MYRPG
SEU==>
DTARPG2
FMT
* ..... *. 1 ...+... 2 ...+... 3 ...+...
4 ...+... 5 ...+... 6 ...+... 7
*************** Beginning of data *************************************
0001.00 C*Define Data Area with *NAMVAR
0002.00 C *NAMVAR DEFN DTA1 21
0003.00 C*Retrieve Data Area with IN
0004.00 C *LOCK IN
DTA1
0005.00 C MOVE 'PUNE' FLD1
10
0006.00 C MOVE *BLANKS FLD2
50
0007.00 C*Concatenate DTA1 value with FLD1 value
and store it in FLD2
0008.00 C DTA1 CAT
FLD1 FLD2
0009.00 C FLD2 DSPLY
0009.01
*MOVEING ‘HELLO’ TO THE DATA
AREA
0009.03 C MOVEL'HELLO' DTA1
0009.04 *UPDATING DATA AREA
0009.05 C
OUT DTA1
0009.06 *DISPLAYING DATA AREA
0009.07 C DTA1 DSPLY
0010.00 C*Unlock Data AREA
0011.00 C UNLCKDTA1
0012.00 C SETON LR
****************** End of data ****************************************
F3=Exit
F4=Prompt F5=Refresh F9=Retrieve
F10=Cursor F11=Toggle
F16=Repeat find F17=Repeat change F24=More keys
Example of Use of Data Area :
In this example we store the name of the
school in the data area. we retrieve the name of school from the data area
through a cl program (CL3) .
In following example, we display the
details of the students. the name of school on display screen comes from the
data area.
First we will create a Data Area SCHOOL and
store the name of the school in that.
DDS for the Physical file (STUD):
Columns . . . : 1
71 Browse PB01U01D/MYDDS
SEU==>
STUD
FMT
A* .....A*. 1 ...+... 2 ...+... 3 ...+... 4 ...+... 5 ...+... 6 ...+... 7
*************** Beginning of data ***************
0001.00
*****************************************************************
0002.00
*
0003.00 * STUDENT MASTER
0004.00
*****************************************************************
0005.00 R STUDR
0006.00 ROLL 3
0 COLHDG('ROLL NUMBER')
0007.00 NAME 10 COLHDG('NAME OF STUDENT')
0008.00 CLASS 2
0 COLHDG('STUDENT
CLASS')
0009.00 SEC 1 COLHDG('CLASS SECTION')
0010.00 K ROLL
****************** End of data ****************************************
F3=Exit
F5=Refresh F9=Retrieve F10=Cursor
F11=Toggle F12=Cancel
F16=Repeat find F24=More keys
(C)
COPYRIGHT IBM CORP. 1981, 2002.
Display File Record (S1):
UUUUUUUUUU OOOOOOOOOO TT:TT:TT
DD/DD/DD
------------------------------------------------------------------------------
NAME..................: OOOOOOOOOO
ROLL NUMBER...........:
999-
CLASS.................: 99-
SECTION...............: O
------------------------------------------------------------------------------
F3=EXIT
Work screen for record S1: Press Help for
function keys.
DDS for the Display file (STUD):
Columns . . . : 1
71 Edit PB01U01D/MYSCR
SEU==>
STUDIN
FMT
A* .....A*. 1 ...+... 2 ...+... 3 ...+... 4 ...+... 5 ...+... 6 ...+... 7
*************** Beginning of data *************************************
0000.10 A*%%TS
SD 20050317 135046
PB01U01 REL-V5R2M0 5722-WDS
0000.20 A*%%EC
0000.30 A DSPSIZ(24
80 *DS3)
0000.40 A
R S1
0000.50 A*%%TS
SD 20050317 135046
PB01U01 REL-V5R2M0 5722-WDS
0000.60 A
CF03(03)
0000.70 A 1 72TIME
0000.80 A 2 72DATE
0000.90 A
EDTCDE(Y)
0001.00 A
1 2USER
0001.10 A 3 2'--------------------------
0001.20 A
---------------------------
0001.30 A ---------'
0001.40 A
COLOR(BLU)
0001.50 A 22 2'--------------------------
0001.60 A ---------------------------
0001.70 A
---------'
0001.80 A
COLOR(BLU)
0001.90 A SCNAME 10A
O 1 35DSPATR(HI)
0002.00 A 23 4'F3=EXIT'
0002.10 A
COLOR(BLU)
0002.20 A 7 5'NAME..................:'
0002.30 A 9 5'ROLL NUMBER...........:'
0002.40 A 11 5'CLASS.................:'
0002.50 A 13 5'SECTION...............:'
0002.60 A SNAME 10A
O 7 34
0002.70 A SROLL 3S 0B
9 34
0002.80 A SCLASS 2S 0B 11 34
0002.90 A
SSEC 1A
O 13 34
****************** End of data ****************************************
F3=Exit
F4=Prompt F5=Refresh F9=Retrieve
F10=Cursor F11=Toggle
F16=Repeat find F17=Repeat change F24=More keys
CL Program CL2:
Columns . . . : 1 71
Edit PB01U01S/MYCLP
SEU==> C
CL3
FMT
** ...+... 1 ...+... 2 ...+... 3 ...+...
4 ...+... 5 ...+... 6 ...+... 7
*************** Beginning of data *************************************
0001.00 PGM PARM(&VAR1)
0002.00 DCL VAR(&VAR1) TYPE(*CHAR) LEN(10)
0002.01 DCL VAR(&VAR2) TYPE(*CHAR) LEN(10)
0003.00 RTVDTAARA DTAARA(SCHOOL (1 10)) RTNVAR(&VAR2)
0004.00 CHGVAR VAR(&VAR1) VALUE(&VAR2)
0005.00 ENDPGM
****************** End of data ****************************************
F3=Exit
F4=Prompt F5=Refresh F9=Retrieve
F10=Cursor F11=Toggle
F16=Repeat find F17=Repeat change F24=More keys
(C)
COPYRIGHT IBM CORP. 1981, 2002.
RPG Program Description:
Columns . . . : 1
71 Edit PB01U01S/MYRPG
SEU==> SCHOO1
FMT
FX .....FFilenameIPEAF........L..I........Device+......KExit++Entry+A....U
*************** Beginning of data *************************************
0001.00 FSTUD
IF E K
DISK
0002.00 FSTUDIN
CF E WORKSTN
0003.00 *
0004.00 C *IN03 DOWEQ*OFF
0005.00 C
03 LEAVE
0005.01 *CALLING THE CL PROGRAM TO FEATCH SCHOOL
NAME FROM DATA AREA
0005.02 *SCHOOL
0006.00 C CALL 'CL2'
0007.00 C PARM SSNAME 10
0008.00 C MOVELSSNAME SCNAME
0009.00 C *LOVAL SETLLSTUDR
0010.00 C *IN90 DOWEQ*OFF
0012.00 C READ STUD 90
0013.00 C EXSR P2S
0014.00 C EXFMTS1
0014.01 C
03 LEAVE
0015.00 C ENDDO
0016.00 C ENDDO
0017.00 C SETON LR
0018.00 *
0019.00
**************************************************************
0020.00 C P2S BEGSR
0021.00 C MOVELNAME SNAME
0021.01 C Z-ADDROLL SROLL
0021.02 C Z-ADDCLASS SCLASS
0022.00 C MOVELSEC SSEC
0023.00 C ENDSR
****************** End of data ****************************************
F3=Exit
F4=Prompt F5=Refresh F9=Retrieve
F10=Cursor F11=Toggle
F16=Repeat find F17=Repeat change F24=More keys
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