I posted an article two weeks ago asking about exiting isql based on a
condition.   One followup article suggested using "return" instead of
"exit".  I tried it out.  It works fine for one batch.  But what I am
doing is to write a big isql script with many "go" in it.  My script need
to access a table which I'm not always sure that it will be there.  So
I would like to build in an error checking in my script.  If the desired
table is not in database, the script should quit immediately with an error
message.  That is, batches after my error-checking batch should not be executed.

Any suggestions of how to do that?

--

Vincent Q. Yin

 . . . . .

Could you show us(again?) a list of some of the things you're trying to
do?  Have you looked at building a stored procedure, i.e., instead of
an isql script, put everything in a stored procedure . . . or maybe a
couple stored procedures.

For example, if you're looking for the availability of a table you
just look in the sysobjects table for the desired database and branch
within the sp accordingly(or return).  

Of course, you can't do any 'dynamic' programming in a stored procedure;
unless you wrote a . . say . .  'sed' script which modifies the sp file
definition, reloads the sp into the database, then executes said
sp . . .

. . . then again I may be getting too fancy or complicated for what you want to do??

Mark
--
Mark A. Parsons

Yes!  I finally figured out why I CAN'T use stored procedures. I need to create

rules and bind them to my tables.  However, CREATE RULE is not allowed in stored

procedures.  Plus, my script is more than 1000 lines long.  It makes me feel
very uncomfortable to make such a long stored procedure.

I appreciate your many articles, Mark.  And I think your suggestions are very
good ideas.  But I'm just too 'strange' here.  Can I exit based on a condition
in a long isql script with many go's ?

--

Vincent Q. Yin

Well, then invoke isql twice. First to check if the crucial table exist,
and then for the real job. Make the decision on shell level. (Or get
sybperl :-)

Not talking of how unconfortable the server will feel. :-) No good
excuse though, as you could always split in several procedures.

I know no way to do so. But I'm not T-SQL guru. Then again is the shell
solution that terribly ugly?
--

Or, I might add, sybtcl.  I do almost all my DB programming in TCL and
TK.  Lots easier than C, and lots more flexible than trying to do
everything in SQL.  

--
=Spencer W. Thomas              |  Info Tech and Networking, B1911 CFOB, 0704
   "Genome Informatician"     |  Univ of Michigan, Ann Arbor, MI 48109

I had a query about sybtcl, but was unable to reply by e-mail.  So
here's the info.

Sybtcl is a code extension to Tcl/TclX/Tk that provides an interface
to dblib functions.  It allows you to submit SQL, retrieve the
results, read TEXT pages, and determine the status of your SQL
(errors, etc.).  It's available from the Tcl "contributed software"
site, which is now

        harbor.ecn.purdue.edu (128.46.128.76)
        /pub/tcl

The current version seems to be 1.2, which works with all the versions
of Tcl/TclX I've tried it with (up to Tcl 6.7/TclX 6.5c).  It doesn't
require TclX, but the installation instructions assume you've got it.

There is one bug I've found, for which I include the patch below.

I also have some TCL procs that (I think) make it slightly easier to
use, and I have a full-blown browser that lets you (more-or-less)
easily investigate database structure and contents (no, it doesn't
do E-R diagrams).

For those of you not familiar with TCL, it's an interpreted extensible
language that is designed for adding command language interface to
tools.  TK is an extension of TCL that provides an interface to X with
a Motif-like look & feel.  In my experience, I can produce "GUI"
programs in a fraction (orders of magnitude) of the time that would be
required to write them in C or another similar language.  See
comp.lang.tcl for more discussion, or look at the code and
documentation.  These are available from the archive site:

        sprite.berkeley.edu (128.32.150.27)
        /tcl

% diff -c sybtcl.c~ sybtcl.c
*** sybtcl.c~   Wed Oct  7 12:58:54 1992
--- sybtcl.c    Tue Nov 24 12:30:44 1992
***************
*** 155,162 ****
--- 155,164 ----
            sprintf(buf,"%d",oserr);
              Tcl_SetVar2(SybInterp,SybMsgArray,"oserr",buf,TCL_GLOBAL_ONLY);

+           if ( dberrstr == NULL ) dberrstr = "";
              Tcl_SetVar2(SybInterp,SybMsgArray,"dberrstr",dberrstr,
                        TCL_GLOBAL_ONLY);
+           if ( oserrstr == NULL ) oserrstr = "";
              Tcl_SetVar2(SybInterp,SybMsgArray,"oserrstr",oserrstr,
                        TCL_GLOBAL_ONLY);

--
=Spencer W. Thomas              |  Info Tech and Networking, B1911 CFOB, 0704
   "Genome Informatician"     |  Univ of Michigan, Ann Arbor, MI 48109