Re: Elevator speech on DB2 development and web enablement?

On 10/4/2015 5:13 AM, Henrik Rützou wrote:

To my best knowledge a trigger, even if it is executed before the I/O,
isn’t able to prevent the I/O being done so triggers are limited unless

you

at the same time as you build in a validation and a way to message back

to

the caller (that is not standard in a trigger) and combines it with
commit/rollback in the caller.

One can use a Before Trigger to prevent an I/O operation! To signal a
failure, have the trigger send an escape message to the caller, which
will be the database manager. The DB manager sees that and percolates
an I/O error back up to the HLL. In the case of an RPG program
performing an UPDATE, the UPDATE operation will receive the I/O error
and this is how the program knows the I/O did not happen.

--
--buck

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