How to cast GlideRecord?

[rickseidencdi]

I'm looking to cast a GlideRecord object into a child class.

What I'm trying to do is fill in a form with a field on cmdb_ci_hardware but I have to do the searching from cmdb_ci.

For example, say that there is a custom field on cmdb_ci_hardware called u_environment.  When I search for a CI, I want to access that field, even though I'm searching from the cmdb_ci table.

I try this

var cmdb_ci=new GlideRecord('cmdb_ci');
cmdb_ci.addQuery('name','SomeHardware');
cmdb_ci.query();
if (cmdb_ci(next)){
  gs.log(cmdb_ci.u_environment);
}

But that returns undefined because the sys_class_name of the cmdb_ci GlideRecord is "cmdb_ci" and the u_environment field is on the cmdb_ci_hardware table.

Is there any way to access that u_environment variable in this case?  I tried doing a query from cmdb_ci and saying Hardware.u_environment is not empty, and it gave "ref_cmdb_ci_hardware.u_environmentISNOTEMPTY".  So I tried cmdb_ci.ref_cmdb_ci_hardware.u_environment, and that crashed my Client Script.

Any help would be appreciated.

[sachin_namjoshi]

you will have to query cmdb_ci_hardware table instead of cmdb_ci table.

Also, DO NOT use GlideRecord in client script since it will get cause performance issues. Use GlideAjax instead.

Regards,

Sachin

[rickseidencdi]

I'm using g_form.getReference, actually.  But I figured it would be easier to understand using a GlideRecord example.  I'm looking to avoid using a Glide Ajax to return the actual record since it will required a database call to figure out the class of the record, and then another call to get the record in its native class.

I could swear I've seen this done before, but I just can't remember how it was done.

[The SN Nerd]

It can't be done using getReference.
If your requirement is onLoad, you could trigger some client-side behaviour with an on display business rule.
The code to "cast" can be seen below:

var sys_id;
var cmdbClass;

var cmdb_ci=new GlideRecord('cmdb_ci');
cmdb_ci.addQuery('name','SomeHardware');
cmdb_ci.query();
if (cmdb_ci.next()){
    sys_id = cmdb_ci.getValue('sys_id');
    cmdbClass= cmdb_ci.getValue('sys_class_name');
}

cmdb_ci = new GlideRecord(cmdbClass);
cmdb_ci.get(sys_id);

[Jace Benson]

You could move the field up to the base table.  Not a great option but stops you from having to do two calls.