Hello Sandeep,
Article is useful but it may confuse others as you mentioned base tables. You can say they as Most used tables.
There are two base tables in servicenow which are
1. Task table
2. cmdb_ci
Base tables are those tables which are extended, but itself is not an extended table.
sys_db_object table is a table of tables .You can check the table in your instance by using following link.
https://YOURINSTANCE.service-now.com/sys_db_object_list.do?sysparm_query=super_class%3DNULL
Or you can check the tables by below link
Tables and Classes - ServiceNow Wiki
Thank You,
Abhishek Gardade
