Enforcing unique numbering

Release version: Australia

Updated March 12, 2026

1 minute to read

Although duplicate numbers are rare, numbering does not enforce uniqueness, by default.

To enforce uniqueness, you can:

Create a before business rule on insert only to check for duplicate values and replace duplicates with the next available number.
Enable a unique index on the table. For more information, see Create a table index.
Note:
While unique indexes ensure data integrity they also prevent any insert involving a duplicate number. This may cause unexpected errors during data entry.

Sample business rule

This sample script can be used as part of a before business rule on insert only to check for duplicate numbers and replace them with the next available number. The following script references a script created in Configure left padding of a system number in a table.

var curNum = current.number + '';
 
if(curNum) {
 
  var recordClass = current.getRecordClassName();
  var now_GR = new GlideRecord(recordClass);
  now_GR.addQuery('number', curNum);
  now_GR.setLimit(1);  
  now_GR.query();
 
  if(now_GR.getRowCount() > 0) {
    var newNum = getNextObjNumberPadded();
    gs.addInfoMessage("The number " + current.number + " was already used by another " +
     recordClass + ". The " + recordClass + " number has been changed to " + newNum);
    current.number = newNum;
  }
}