Does anybody think there might be some interest in an ISAM driver for
PostgreSQL?  I've written a functional alpha that allows PostgreSQL to
be a drop in (or as easy as reasonably possible) replacement for an ISAM
file system driving a COBOL application.  It is a STL based thin wrapper
around libpq that generates queries on the fly from traditional ISAM
(read, write, start, etc.).  It was made to be generic, allowing porting
to various COBOL vendors' compilers with minimal effort.  Error
conditions are returned as traditional COBOL error codes.  The main
drawback to the system is that performance is highly sensitive to
network latency (as are most COBOL applications).

Unlike traditional hybrid COBOL which use ESQL, this system could run
native COBOL code with reasonable performance in any COBOL application
which allows linking to an external ISAM file system.  This is very much
a work in progress, built strictly for my own needs; but could be made
to be useful in a more general sense.  I'm thinking about cleaning up
the code and setting up a project on sourceforge.

PostgreSQL is uniquely suited for this purpose because of its
portability and rich syntax.  A good example is postgres's array type
which maps very elegantly to COBOL's OCCURS syntax.

Regards,
Merlin



Mon, 16 Feb 2004 15:32:39 -0500
"Merlin Moncure" <merlin.moncure@rcsonline.com>
ISAM driver for PostgreSQL
Merlin Moncure wrote:
> Does anybody think there might be some interest in an ISAM driver for
> PostgreSQL?  I've written a functional alpha that allows PostgreSQL to
> be a drop in (or as easy as reasonably possible) replacement for an ISAM
> file system driving a COBOL application.  It is a STL based thin wrapper
> around libpq that generates queries on the fly from traditional ISAM
> (read, write, start, etc.).  It was made to be generic, allowing porting
> to various COBOL vendors' compilers with minimal effort.  Error
> conditions are returned as traditional COBOL error codes.  The main
> drawback to the system is that performance is highly sensitive to
> network latency (as are most COBOL applications).
> 
> Unlike traditional hybrid COBOL which use ESQL, this system could run
> native COBOL code with reasonable performance in any COBOL application
> which allows linking to an external ISAM file system.  This is very much
> a work in progress, built strictly for my own needs; but could be made
> to be useful in a more general sense.  I'm thinking about cleaning up
> the code and setting up a project on sourceforge.
> 
> PostgreSQL is uniquely suited for this purpose because of its
> portability and rich syntax.  A good example is postgres's array type
> which maps very elegantly to COBOL's OCCURS syntax.

Don't know --- no one has asked for this before.  You could create a
project on gborg.postgresql.org and see if folks find it useful.

-- 
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 359-1001
  +  If your life is a hard drive,     |  13 Roberts Road
  +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073

Tue, 17 Feb 2004 11:16:09 -0500 (EST)
Bruce Momjian <pgman@candle.pha.pa.us>
Re: ISAM driver for PostgreSQL