Update deleting records?

Greetings

The following SQL statement

UPDATE "wwwlog" SET "GraphicStatus"=true WHERE "LogID"=1

will delete record with LogID=1.
What am I doing wrong or is it a bug?

Perhaps there is a better way of doing what I need. I am using postgresql to
log access to web pages on a nt4 server. I use ODBC to link to Postgresql on
a linux machine. The logs are being inserted fine. When querying the logs I
need to identify between pictures and pages. The best way for me would be to
exclude bmp, Jpg and Gif entries. These are done with NOT LIKEs in the WHERE
statement at the moment. The problem is now performance with a 35 second
delay in a query of this type. To reduce the delay I thought of using two
additional Boolean fields. The first would indicate that the record is for a
.bmp, .jpg or .gif and the second would tag that the record has already been
tested for these file type. Only records without the second tag would be
updates using the LIKE in the WHERE. This should reduce the number of LIKE
statements in the queries and therefore reduce response time. This seems a
bit like scratching your ear with your toe, a bit awkward. Anyone know of a
better approach?

As a side, how do I delete a column? What windows based package would be
recommended for the admin of postgresql. PGAccess I am finding to be a
little limited. PGSQL is very cryptic.

Regards
Warren