question Re: How to make an already created custom table extend another custom table? in Developer forum

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

UPASANA2 — Fri, 11 Dec 2015 09:39:30 GMT

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

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

kumarg — Fri, 11 Dec 2015 10:00:33 GMT

Here is a script to extend an existing table.

Important Notes

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

Steps to extend table

Elevate your privileges to security admin
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);

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

UPASANA2 — Fri, 11 Dec 2015 10:11:17 GMT

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?

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

Vinobalu — Fri, 11 Dec 2015 10:33:58 GMT

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".

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

UPASANA2 — Fri, 11 Dec 2015 11:11:15 GMT

I did, but it deleted all the existing records. Is there any way to get the records back?

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

Rushit Patel2 — Fri, 11 Dec 2015 14:04:12 GMT

hi Upasana,

there is module called..deleted records..in that filter records with your table name..select all records..go down to list dropdown actions..there will be undelete option.

i hope it helps.

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

UPASANA2 — Fri, 11 Dec 2015 14:52:22 GMT

Hi Rushit,

I tried the same, but no records were found there.

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

Vinobalu — Fri, 11 Dec 2015 18:37:56 GMT

Before you extend the table export all the data in excel and then you extend the table. After extended import the data once again.

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

UPASANA2 — Sat, 12 Dec 2015 10:01:33 GMT

its already deleted. can we get it back by raising a HI request?

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

Tanaji Patil — Sat, 12 Dec 2015 10:37:04 GMT

Hi Upasana,

Your records are not deleted so you won't get those in the deleted records module. As you have modified the table it extends the records are not shown here but they are still present in the table it was extending.

To get the records back try setting the 'extends table' field value of the extending table back to what it was earlier. This will show you the records back in the table.

Export all the records in excel and then do what you want.

But instead of changing the 'extends table' value of already existing table I would recommend deleting this table and creating exact table again(this time extending the table which you want) and then import the excel you exported earlier into this table. To extend any table make sure the extensible field is checked on that table you want to extend.

Follow these steps after taking excel export-

1. Go to System Definition > Tables.

2. In the list view set the extensible to true for the table which you want to extend.

3. Create the deleted table again(as told above) this time extending the table in step 2.

4. Import your data into your new table using Easy Import.

Thanks,

Tanaji Patil

--Mark correct/helpful if it helps solving your issue.

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

UPASANA2 — Sat, 12 Dec 2015 11:05:34 GMT

Hi Tanaji,

I am not able to view the records after changing the extended table back to what it was earlier. It showed unique key vioalation.

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

Tanaji Patil — Sat, 12 Dec 2015 11:13:02 GMT

Please delete data/customization added after you changed the extends table value and try.

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

UPASANA2 — Sat, 12 Dec 2015 11:34:21 GMT

No customization was done. Though its showing error, it should have shown the list of records right?

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

Tanaji Patil — Sat, 12 Dec 2015 11:45:28 GMT

Yes it should show the records. Hope you are making 'Table Field Validation' BR active false and setting the 'extends table' value to exactly what it was when the records were created.

I checked again on demo021 and I was right. It shows the records back.

Tables used are Table 1 and Table 2.

If this is not helping you then you should go with raising HI ticket.

Thanks,

Tanaji Patil

--Mark correct/helpful if it helps you solving your issue.

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

UPASANA2 — Sat, 12 Dec 2015 19:15:03 GMT

yes, i will try to resolve. if not will raise a HI ticket. Thank you

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

paulmorris — Mon, 14 Dec 2015 01:56:19 GMT

You did it in your DEV environment so you can always clone PROD back into DEV and run the exercise again.

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

verdakosnett — Thu, 15 Dec 2016 18:07:20 GMT

Great script but it doesn't work in scoped apps

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

paulmorris — Wed, 21 Dec 2016 01:26:33 GMT

It shouldn't matter - run it in global and you won't have to worry about running it again, as the change will be made to your application.

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

ranjanireddy — Mon, 15 Jan 2018 10:38:18 GMT

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

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

chris_lo — Tue, 11 Sep 2018 16:55:49 GMT

Customer's should not be using this API. If you do so it is at your own will. If something like this is needed please consult support. Do not perform this action on your own.

Staff Technical Support Engineer

Chris Lo