Help with a Trigger

Hello all. I'm new to this forum and having been searching all day. I'm currently taking an Oracle class for Grad school and i'm trying to wrap my head around a problem using triggers.

I basically have a table created where it lists Item information along with with a price. An Item_ID is the primary key for that table.

I've been asked to create a separate table for historical purposes and create a trigger that will update and create an entry in the new historical database listing the Item ID along with it's new price and old price.

How can I create a trigger that will reference or update a new table every time i update the current ITEM table with a new price?

This is a SQL Server forum. Oracle triggers vary greatly from SQL Server triggers. You really need to do a Google search for "Oracle trigger" and/or find an Oracle-specific forum.