How to make an already created custom table extend another custom table?

[UPASANA2]

How to make an already created custom table extend another custom table?

[kumarg]

Here is a script to extend an existing table.

Important Notes

1. Always test first in a test or development ServiceNow instance
2. This script does work with tables with data in them, however I suggest only running this on new or empty tables.
3. This is a manual step and isn't captured in an update set.

Steps to extend table

1. Elevate your privileges to security admin
2. In scripts - background run this script (replacing variables as needed)

//Replace <source_table> with the table you want to extend 
//Replace <table_extension> with the table you want to extend to, like cmdb_ci or task 
var table = '<source_table>'; 
var old_parent = ''; 
var new_parent = '<table_extension>';   
var changer = new GlideTableParentChange(table); 
changer.change(old_parent, new_parent);

[UPASANA2]

Hi,

I have been trying script it from many days. But I get this message when I run the script-> Hierarchy change for u_cpar ignored because new base table 'u_business_services' does not have (but needs) a sys_class_name field

we can extend inbuilt tables using this script, but not custom tables. Is there any other way which we can make this script work?

[ranjanireddy]

It worked for me in Istanbul instance. Both my tables are newly created and then made one of the table as parent to another table. Good script. Thank you

[Vinobalu]

Hi Upasana,

1. Deactivate the business rule "Table Field Validation".

2. In the list View extend the custom table.

3. Finally activate the business rule "Table Field Validation".