Pear::DB - Getting the name of columns

Hello together, I'm trying to set up a Class wich wraps access to database tables. You only have to set the tablename and keyname and can do select, insert, update, delete. The Data of the table will be stored in a class-array. The values can be manipulated by writing into the array and call the update function ... etc. The class using the PEAR::DB Object to send querys and check for errors. Now I want to initialize the Class with loading all column names and save them into a class array. This array I need to perfome the insert or update query from PEAR::DB. Is there any function wich returns the colum names (without doing an "SELECT somthing FROM mytable" and then get the info from the result array or doing the tableInfo() function on the result) or exists an Ansii-SQL-Query to get this information from every DB? Sorry for my bad english. Thanks, Nils Becker