如何避免定时删除备份作业执行后，无备份文件存在#

DECLARE                            --此过程避免在定时备份执行失败时删除全部备份集，此过程建议每天定时执行，替代原有的单一删除一定时间前备份集的删除策略
        CON           INTEGER;     --备份集数量
        BACKUPSETNAME VARCHAR(100);--最近一个备份集名字
        CHECK_FLAG    INTEGER;     --备份校验标记
BEGIN
        --添加备份路径   /opt/dmdbms/data根据现场实际需求进行配置
        CALL SF_BAKSET_BACKUP_DIR_ADD('disk', '/opt/dmdbms/data');
        --赋值CON为本库全量备份集数量
        select
                count(*)
        INTO
                CON
        from
                V$BACKUPSET
        where
                true
            and "TYPE"       =0
            AND "RANGE#"     =1
            AND "OBJECT_NAME"=
                (
                        select sys_context('USERENV', 'DB_NAME') from dual
                );
        --判断是否存在可用全库备份集,具体配置请合理评估后决定  CON值至少大于1，至少保留一次备份
        IF CON > 2 THEN
                --赋值BACKUPSETNAME为本库最近一次全量备份集名称
                select
                        BACKUP_PATH
                INTO
                        BACKUPSETNAME
                from
                        V$BACKUPSET
                where
                        true
                    and "TYPE"       =0
                    AND "RANGE#"     =1
                    AND "OBJECT_NAME"=
                        (
                                select sys_context('USERENV', 'DB_NAME') from dual
                        )
                order by
                        BACKUP_TIME desc LIMIT 1;
                --对本库最近一次全量备份集进行备份有效性校验
                SELECT
                        SF_BAKSET_CHECK('DISK', BACKUPSETNAME)
                INTO
                        CHECK_FLAG
                FROM
                        DUAL;
                IF CHECK_FLAG = 1 THEN
                        --删除一定时间以前的备份
                        call SP_DB_BAKSET_REMOVE_BATCH('DISK', SYSDATE-180);
                END IF;
        END IF;
END;