An auto incrementing column automatically generates a unique, auto incrementing number for each new record. Auto increments can be useful for when you need to uniquely identify records within your data model, for example, if you want to give your users the option to edit an individual record.
Please note, when you delete a record the auto incrementing record does not re-number. This can leave gaps in your numbering and also means that the auto incrementing number is not appropriate for counting up the number of records in your data model.
Notice, each table comes with a field called "Id" by default. This field is an auto incrementing field that cannot be deleted or modified. To the left of the Id field Dittofi displays the row count.