# 3509 Using Triggers with Live Result Sets That Access a Subset of Available Fields Can Cause AV

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I added triggers to the db server. That means that TDBISAMEngine.TriggerCallback does what it should: look for the
trigger type and start the whole stuff.

In the client, I create a DBISAM query object with SQL = 'SELECT a, b FROM table WHERE ID=123'. a is a string, b is a BLOB field. That query is live.

Then I edit that query:

query.edit;
(query.fieldbyname('b') as TBlobField).LoadFromStream...
query.post;

That .post cause an exception in the server.