Q:

How to use simplify()

i have my Vector Data saved in a PostgreSQL PostGIS enabled Database. 
The Data im displaying is very detailed, i want to simplify it through the simplify() method of Postgis.  
I duplicated one of my tables (for test purposes to not mess up the real thing) and then used the simplify func"select ... simplify(...)..."
I got a result and inserted into the geom part of my new table. 
After i created a new layer with this table as spatial information, whenever i click on Layer preview, im not greeted with a map, but with a download prompt for an xml which tells me i have an error. 
Am i using the function wrong ??  or is my approach inside of geoserver wrong ?? 
Could i possibly save my current data as a shapefile, then simplify this and then let it be processed with pg2sql or something like that ?? 
Whenever i add the Layer to my Geoserver and press compute Bounding Boxes, geoserver comes up with 0, -1, 0, 1 . 
Sorry if i have alot of questions but im really really stuck. 

A:

The problem probably is that GeoServer needs to find your new table in "geometry_columns"
You can use the function Populate_Geometry_Columns to put all the data about your table in the right place. 
About simplifying, Paul Ramsey also have a great approach in his blog
HTH
Nicklas

