Patrick O'Keefe wrote:
On Fri, 23 May 2008 16:07:28 +0000, Ted MacNEIL
<[EMAIL PROTECTED]> wrote:
What are *ISPF* tables?
An internal data structure with user defined fields an multiple rows.
...
Programming with them is not trivial.
...
But not terribly difficult, either, and VERY useful. I done very little
ISPF programming for 20 years, but I've written a bunch of
NetView-based REXX stuff that would have been a lot easier if
NetView had a "table" concept. My pseudo-table support in NetView
has really made me appreciate ISPF table support ... and all I did
was the display and find parts; no add, mod, delete, etc.
Pat O'Keefe
For small ISPF-based applications ISPF tables can be much simpler than
interfacing to a full-blown database product, esp. with the efficient
integration between ISPF tables and ISPF skeletons and parameterized
JCL/file creation.
Limitations include exclusive update enqueues by table name across all
users, and the need to rewrite the entire table at closing if any row is
updated in a non-temporary table. The former requires user-specific
table names for even temporary tables for user-specific data (e.g., a
prefix of the userid or of the ASID). The latter means that large
number of rows can lead to poor performance (and if so long that users
are tempted to cancel applications during a table close of a permanent
table, the table is easily corrupted).
Another nastiness that can be a problem during application testing or if
the ISPF application terminates abnormally, is that there is no
automatic close for tables. A table left open can result in unexpected
later failure of a subsequent TBOPEN, either by that user, or by another
user if it is a permanent table that is shared. Either the application
must be designed to work around this, or the user will have to
LOGOFF/LOGON to eliminate any hanging table references.
--
Joel C. Ewing, Fort Smith, AR [EMAIL PROTECTED]
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