As a ServiceNow developer it is very important to know what is a list of table extensions, or parent before you start your configuration and coding to eliminate custom change so you can use ServiceNow out-of-box (OOB) as possible.

I would like to introduce two easy way to find a list of table extensions, or parent below:

Method One using TableUtils()

We are going to use "Script - Background" to get a list of table extensions, or parent:

1. Review a list of table extensions Results: total 15 extended tables is displayed
2. Review a list of table parents

Method Two using sys _db_object

1. Review a list of table extensions, or parents
2. * Search sys_db_object.list via Filter Navigator
   
   • Search "HR Case" on Extends table filed and then a list of table extensions will be displayed
     
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   • Display HR Case record by clicking "HR Case" under "Extends table" so you can see a parent
     
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If you are good for script, I recommend to use TableUtils() method, but if you are not good for script, you can use sys_db_object.list method. One most advantage of TableUtils method can review a list of all related parent, but sys_db_object.list method can only get a direct parent.