Subject AW: [firebird-support] Check previous records in the table before table update
Author Olaf Kluge
Hello Kukiejko.

You mean that you can only update a dataset with time is not null? First,
you should not use a column-name like "time". In this case you mean ID 233
is possible and ID 234 not? If you use a trigger, you'll never can update
the time-column because it is never possible if the old time-value is null
and the new is not null.

. before update .

If(old.time is null and new.time is not null) then


New.time = old.time



Or would you only update the time column for the record with the next ID
after last time-filled-record?



I use Firebird 2.5 for Windows.
I need to create UPDATE TRIGGER for Table A, but
UPDATE for the Table A for row ID=x is only possible if TIME column for ID<x
is >not< [null]. For example I can update Time column for row ID=234 but it
should be not possible to update Time column for row ID=235.
How can I do it on the Firebird server (using eg. Trigger, functions or

229 | 07.06.2013, 18:06:35.871
230 | 07.06.2013, 16:42:52.941
231 | 07.06.2013, 16:42:53.286
233 | 07.06.2013, 16:42:53.607
234 | [null]
235 | [null]
236 | [null]
Thank you for any feedback or example

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