Require unique value on a field

[carlh]

Good morning.

How can I set up a field to query the table for unique values before allowing me to save a record to the table?

I wasn't sure how to word it but here's what I am doing.   We are creating new vendors and need to check and make sure the "VendorID" field is not already in the table.

I'm hoping I can do this as a client script so it can be caught while on the form and fixed.

Could someone provide a script?

Table "core_company"

Field Name: "u_vndr_id" (string)

I have several field where I could use this as well so hoping it's as easy as changing the table and fields.

Thanks!!! Carl

[Aaron Schmid]

Just to add to this...

I wanted an alert onChange version in a client script and this worked for me...

function onChange(control, oldValue, newValue, isLoading, isTemplate) {

  if (isLoading || newValue === '') {

  return;

  }

  var gr = new GlideRecord('table_name');

  gr.addQuery('field_name', newValue);

  gr.query();

  if(gr.hasNext()){

  g_form.setValue('field_name', ' ');

  alertNow ({header: 'custom text', title:'custom text', message: 'custom text', image:'url', imageWidth:'250', imageHeight:'250' });

  }

}

[Damhoej]

https://docs.servicenow.com/bundle/jakarta-platform-administration/page/administer/field-administration/task/t_RequiringUniqueValuesForAField.html

It is for the Jakarta version, but I will imaging that the solution is the same for other newer versions.