Best Practice
http://technet.navision.com/usered/B...ata_source.htm
A CounterField is typically used to ensure that a record inserted in a form is given a line number that corresponds to the actual, sequential position in the form.
For example, if a new line is inserted between lines 3 and 4, the new line is given line number 3,5. This is used for example in the CustWorksh in the standard application.
To achieve this effect the field given as CounterField should be given as index on the database table.