Constraint 0=1

[ranga1970]

Folks,
this is first time i am working for production support, I did develop lot of projects, so sorry for bombadring with stupid question, here is my todays question

in the constraint I find 0=1 and this is link is used to do bulk load using ORABULK, can some tell me what does this mean

thanks
ranga

[kcbland]

This can never evaluate to TRUE, so this constraint is equivalent to @FALSE. If it's connected to a ORABULK stage, chances are the data file being used is generated by a second output link.

Because the ORABULK stage has HUGE overhead, a trick a lot of customers were told to use is to let DataStage generate the control file, but not the data file. A second link would output the data file. An after-job routine would actually execute sqlldr and either dynamically update the control file to use the other file instead of the empty one the ORABULK stage generated, or blow away that file and either symbolic link to the real one or rename the real one to what the control file uses.

Either way, the purpose is to bypass the ORABULK stage generating the actual data file to load.

[PhilHibbs]

...in the constraint I find 0=1...

I just use a constraint of 0 to disable output from a stag for testing purposes. I often have this as one or more job parameters, e.g. "Create_CSV" and "Create_IDoc" defaulting to 1 and 0 at the project level. When the project goes live, the defaults are swapped.

[vmcburney]

Another example of how a simple annotation in a job could make life so much easier. I think whenever you do something unconventional in a job you should put an annotation on the job canvas.

[PhilHibbs]

Another example of how a simple annotation in a job could make life so much easier. I think whenever you do something unconventional in a job you should put an annotation on the job canvas.

I wouldn't describe using a comparison or a zero value in a boolean condition to be "unconventional".

[chulett]

All Vince meant was that the 'conventional' DataStage constraint would use @FALSE to shut down a link. Much less confusing for peoples not intimately familiar with 0 and 1 and which is true and which is false.

Or at least that's my mind reading attempt for the morning.