Thanks: I have a large table (40 million+ rows) that I generated with "copy into" statements using several 1g txt files. The table was subsequently subjected to an "order asc" statement and now I need to have a sequence put on it and there I have a problem. A small simple test table illustrates the problem as follows: sql-> create table test (name varchar(10)); sql->alter table test add column seq serial; Error: ALTER TABLE ADD COLUMN: adding column with key constraint not implemented I have tried several different ways to generate a sequence in the table without success, including insert/select and auto_increment. I have encountered the error "primary key constraint violated". The only way I can get it to work is by adding one row at a time and with 40million rows....well. Sorry about my naivete, but can someone tell me what I am missing. Thanks, George H