default value from a sequence default value for explicit NULL columns default value from a sequence specify sequence.nextval as the default default value from a sequence default value from a sequence default value from a sequence default value for explicit NULL columns default value from a sequence default value from a sequence default value for explicit NULL columns default value from a sequence default value from a sequence specify sequence.nextval as the default default value from a sequence default value for explicit NULL columns default value for explicit NULL columns default value from a sequence default value for explicit NULL columns default value for explicit NULL columns specify sequence.nextval as the default default value for explicit NULL columns default value for explicit NULL columns default value for explicit NULL columns default value for explicit NULL columns default value for explicit NULL columns default value from a sequence