Does a trigger and the event that trigger follow separate processign paths?

We have a process that inserts rows into a table but does not do good error checking. We can't change the process so we need to do error checking after the fact. We will reject records that have a specific value in a non key non unique varchar field. The process is reading a text file and inserting it into a table

three oprions have been proposed and any input would appreciated

1- have a trigger that does a before insert looking for the specific value in the incoming data and stopping the insert or causing it to fail. This getts at the subject line if the trigger tries to stop insert what happens? do they follow spearate paths or does the insert wait for trigger to finish

2 - have a trigger that does a delete after to get rid of bad data. this however consumes resources and lets bad data into table even if for a short time

3 - maybe somekind of constriant that prohibits the bad value from bieng inserted?

any ideas greatly appreciated Received on Thu Jun 10 1999 - 18:37:12 CDT