Using & Exploiting SELCOPY

Objectives
On successful completion of this course, attendees will be able to:

• describe the flow of a SELCOPY job
• use SELCOPY''s unconditional and conditional selection logic
• read, write and manipulate datasets with SELCOPY
• use dynamic allocation in SELCOPY
• print datasets using different formats and tailor standard SELCOPY printout to meet specific user requirements
• code SELCOPY control cards to construct and expand records
• write and test SELCOPY subroutines
• interpret error messages from SELCOPY
• perform SELCOPY arithmetic and conversion functions
• read, write and update VSAM files using SELCOPY
• use POS LRECL effectively
• read, write and update DB2 tables using SELCOPY
• use the SELCOPY Interactive feature of SELCOPY Interactive to run and debug SELCOPY programs.

Who Should Attend
Programmers and operational support staff (e.g. schedulers, operations analysts, JCL writers and operators who perform these duties) who will be using SELCOPY for program development and testing or for setting up operational systems as well as all others who want to learn how to exploit SELCOPY to the full.

Prerequisites
Knowledge of the JCL and dataset organisation concepts of the systems used by attendees is required. Knowledge of TSO and ISPF would be beneficial.

Duration
2 days

Course Code
SEF


Contents

Introduction to SELCOPY
SELCOPY program flow; control card rules; processing in-stream data; JCL requirements; SELCOPY printed output.
This segment introduces the way SELCOPY works and the JCL required to execute a SELCOPY program. The standard SELCOPY output is fully explained.

Reading and writing files
READ control card; NORDW; using a work area: WORKLEN, INTO; READ examples; WRITE control card; WRITE for printing; printing literals, WRITE for copying files; FROM; READ and WRITE examples; CAT control card; using dynamic allocation: DEFER, CLOSE; interpreting error messages: control card errors, select time errors, warning messages at the end of job, SELCOPY return codes.
This is the ''copy'' part of SELCOPY. How to copy files of any format is taught, and the way printing is performed in SELCOPY is explained.

Selection and modification
Fields and POS; logical operations: IF, THEN, ELSE, AND, OR, THENIF, ELSEIF; variable position data; using the pointer; moving and modifying data; further selection techniques: STOPAFT, INCOUNT, EOF, GOTO GET.
This is the ''selection'' part of SELCOPY. This segment shows how to locate and test fields within a file record, how to change data, and how to utilise fully the SELCOPY workarea.

Branching & subroutines
Unconditional branching: GOTO label, GOTO GET, GOTO EOJ, GOTO CANCEL; subroutines: PERFORM, RETURN.
This segment teaches how to code and use SELCOPY subroutines.

Arithmetic and conversion
Zoned and packed decimal; ADD; SUB; MULT; DIV; data conversion: packing and unpacking, CVCP, CVPC.
This segment describes the arithmetic functions available in SELCOPY. Particular attention is paid to the format of data required for these.

Report writing
Standard SELCOPY output; standard output modification: NOPRINT, NOPCTL, NOPTOT; modification of the report: REPORT, HEAD, PAGEDEPTH, PAGEWIDTH; spacing in reports; SPACE, LINE: dates in SELCOPY: POS DATE; other features for report writing
Forget COBOL. This segment shows how SELCOPY can produce a report as good as any high-level language report.

Using LRECL
POS LRECL; variable length records; merging files
This segment is essential for variable length files. Using userpointers as a base it shows how SELCOPY can merge and combine variable length files.

Using DIR and DIRDATA
DIR and DIRDATA options of READ; distinguishing between directory and member records; EOMEMB flag.
This segments shows how to use SELCOPY effectivelyin order to interrogate partitioned datasets.

Processing VSAM files
VSAM file organisation; reading VSAM files sequentially: using STARTKEY, STARTREC and STARTRBA; reading VSAM files directly: KSDS by KEY, RRDS by REC, ESDS by RBA; updating VSAM files: UPDATE, INSERT, DELETE; adding to the end of an existing file; overwriting: REUSE.
This segment details all possible retrieval mechanisms available with SELCOPY, with emphasis on direct retrieval by key of a record from a VSAM KSDS

Processing DB2 data
Accessing the DB2 subsystem; SQL statement types; Immediate and prepared statements; Selecting, Inserting, updating and deleting data from DB2 tables;accessing DB2 information from SQLCA, SQLDA, et cetera.
This segment details how DB2 data may be accessed and amended using SELCOPY.

SELCOPY Interactive
What is SELCOPY Interactive; invoking SELCOPY Interactive; debugging SELCOPY jobs; setting break points; displaying work area storage, pointers, et cetera.
This segment introduces the new SELCOPY Interactive feature, and shows how it may be used to run and debug SELCOPY jobs.