RTVFLDARR RETRIEVE FIELD ARRAY TAADBHF |
The Retrieve Field Array command retrieves an array of field names
that exist in a physical file or a single format logical file. A
corresponding multiple occurrence data structure is also returned
with the detail information about each field. Up to 199 fields in a
file are supported with the basic method. Up to 998 fields are
supported with an optional technique.
Although a command exists for the basic method, it cannot be used
because the size of the multiple occurrence data structure exceeds
the size of the largest variable allowed in a CL program.
The intended use of the tool is in a HLL program where the CPP would
be used directly.
RTVFLDARR escape messages you can monitor for
---------------------------------------------
TAA9891 The file is not a physical or logical file.
TAA9892 More than 199 fields exist (see later discussion).
TAA9893 The file has more than one format.
Escape messages from system commands will be re-sent.
Sample RPG code for Basic Method (up to 199 fields)
---------------------------------------------------
The following RPG code shows the intended use and is in a format that
may be copied to an RPG program:
E* Define array and multiple occurrence DS used by RTVFLDARR
E FLN 200 10
IFLNDS DS
I 12000 FLN
I* CPP for RTVFLDARR
I 'TAATOOL/TAADBHFR' C GETFLD
I* Externally described DS supplied by RTVFLDARR
IFLDDS E DSTAADBHFP 200
.
.
C* Call CPP of RTVFLDARR
C CALL GETFLD Rtv fld arr
C PARM FILE 10 File
C PARM LIB 10 Library
C PARM FLNDS Field names
C PARM FLDDS Field info
Do one of the following sets of code depending on your needs:
C****************************************************************
C* *
C* Access every DS entry. The field name is in WHFLDE. *
C* *
C****************************************************************
C Z-ADD0 FX 30 Inlz index
C GETFLD TAG Get field
C ADD 1 FX Bump index
C FX OCUR FLDDS Set occur
C WHFLDE IFNE *BLANKS Some field
C*
C* Use the field names in the mult occur DS such as WHFTXT.
C*
C GOTO GETFLD Loop back
C ENDIF Some field
C****************************************************************
C* *
C* Access a single field name and the corresponding *
C* DS fields *
C* *
C****************************************************************
C* To access a single field name
C Z-ADD1 FX 30 Inlz
C FIELD LOKUPFLN,FX 20 Lookup
C* If not found, handle error condition
C N20 DO Not found
C*
C*
C ENDDO Not found
C* Name was found, position mult occurrence DS
C FX OCUR FLDDS
C* Use the field names in the mult occur DS such as WHFTXT.
A second format which uses the field names WUxxx instead of WHxxx is
also available by the name of TAADBHFQ. It is intended for use when
two files will be processed and both need the RTVFLDARR function.
Accessing a file with more than 199 fields using the Basic Method
-----------------------------------------------------------------
If a file has more than 199 fields, the first 199 may still be
accessed with the Basic Method. You must place 'GT199' in the first
5 positions of the FLNDS data structure. This specifies that the
TAA9892 escape message will not be sent.
There is no indication that the file has more than than 199 fields.
To determine this, use a command like RTVDBFA. and the MAXFIELDS
parameter.
Accessing a file with up to 998 fields using the Optional Method
----------------------------------------------------------------
The optional method allows a file to have up to 998 fields. Note
that this method can be used for files with fields from 1 to 998.
The following RPG III code may be used:
E FLN 999 10 Field names
IFLNDS DS
I 19990 FLN
I* Externally described DS supplied by RTVFLDARR
IFLDDS E DSTAADBHFP 999
I 'TAATOOL/TAADBHFR2' C GETFLD
.
.
C* Call CPP of RTVFLDARR
C CALL GETFLD Rtv fld arr
C PARM FILE 10 File
C PARM LIB 10 Library
C PARM FLNDS Field names
C PARM FLDDS Field info
The process of the data is the same as for the Basic Method.
Command parameters *CMD
------------------
Note that while the command form exists, it cannot be used because
the size of the FIELDINFO return variable exceeds the largest size of
a CL variable. The command is intended only for documentation. The
function must be accessed using a HLL program.
FILE The qualified name of the physical file or the
logical file with a single format to be retrieved.
The library defaults to *LIBL. *CURLIB may also be
specified.
FIELDS The array which contains the field names. It must
be declared as 2000 bytes and contains up to 199
field names. The first blank field name indicates
the end.
FIELDINFO The multiple occurrence data structure that
describes the detail field information. The data
structure is intended to be defined by the file
TAADBHFP and will contain 199 occurrences. If
retrieved to an RPG program (by using the CPP
directly), it is not necessary to describe the
length of the entire data structure.
Restrictions
------------
The command cannot be used in a CL program because the length of
FIELDINFO exceeds the largest size CL variable.
Only a file with a single format may be named. This includes any
physical file or a logical file with a single format.
Only a file with a single format may be named with up to 199 fields
for the Basic Method.
A file with up to 999 fields may be named for the Optional Method.
Prerequisites
-------------
The following TAA Tools must be on your system:
SNDESCMSG Send escape message
Implementation
--------------
None, the tool is ready to use:
Objects used by the tool
------------------------
Object Type Attribute Src member Src file
------ ----- --------- ---------- -----------
RTVFLDARR *CMD TAADBHF QATTCMD
TAADBHFR *PGM RPG TAADBHFR QATTRPG
TAADBHFR2 *PGM RPG TAADBHFR2 QATTRPG
TAADBHFP *FILE PF TAADBHFP QATTDDS
TAADBHFQ *FILE PF TAADBHFQ QATTDDS
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Added to TAA Productivity tools May 1, 1996
