Is there a way to detect which fields are being changed from a Business Rule?

[Patrick Schult2]

The short story is - I have a need to know which fields are changing in the "current" object that's available in a Business Rule. I've seen a post on ServiceNowGuru about this but it involves J2JS, which isn't available in non-global application scopes.

If it helps, the use case is basically that there needs to be a separate change log of things that have happened to the record, and I don't want to hard code a list of fields to check for changes when this Business Rule runs.

[Shiva Thomas]

Hi Göran,

Wonderful solution! Only two lines... I'm impressed!

I can't do Endorsements, but this one deserve it.

[Patrick Schult2]

This is a great solution! I can loop through all these fields in current, check them for changes, and write them out to my log very easily. Thanks!

[Shiva Thomas]

Yep, more elegant solution than mine...

"The best line of code is the one you don't have to code!"

[Patrick Schult2]

Thanks Shiva - that works great. I was really hoping there was a package like GlideRecordUtil (but for scoped apps) that would just spit out which fields were changing.

In my case, I didn't want to watch for changes on all fields, but rather a specific, known set of fields. To accomplish this, I created a new Dictionary attribute (sys_schema_attribute) record that I then attached to my fields. In this way, I don't have to hard code the list of fields I care about, I can change them on the fly from the dictionary.

// There is a custom dictoinary attribute for noting which fields in this table should create log entries when changed. Query for fields with that attribute.
var fieldsToAudit = [];
var fieldsGR = new GlideRecord('sys_dictionary');
fieldsGR.addQuery('name', current.getTableName()).addCondition('attributes', 'CONTAINS', 'u_create_change_log');
fieldsGR.query();
while (fieldsGR.next()){
         fieldsToAudit.push(fieldsGR.getValue('element'));
}
gs.debug('Fields to audit: ' + fieldsToAudit.toString());

// For every field that has this attribute, check to see if it changed, and if it did, create a log record.
for (i =0; i < fieldsToAudit.length; i++){
         // Create records in the logging table.
         // In order to detect a change in a field, you need to use the GlideElement representation of the field, which we don't have. At this point, all we have is a string field name like "number" or           "use_detail".
         // Fortunately, GlideRecord has a getElement method that will provide you the right object for the specified field name.
         var currentField = current.getElement(fieldName);
         var previousField = previous.getElement(fieldName);
         if (currentField.changes()){
                   gs.debug(fieldName + ' was changed. ');
                             // Create a record in the logging table.
                   } else {
                           gs.debug(fieldName + ' was not changed.');
                   }
}