Assigning item IDs can prove a very complex task if using non-transparent IDs, because you can never be sure which was the last number entered. You can select an option allowing the program to automatically assign ID to any new item entered.
To automatically assign IDs, you have to define general data in the Program Parameters.
Using Semi-transparent IDs
To create such Items register where the first three digits are reserved for item category code, the remaining seven digits should make up a variable consecutive item ID.
Below you can see settings for generating item IDs:

Click
to create a new entry in the Items register. You will see displayed three question marks:

Trying to save an ID before entering item category (that you selected for code of constant), returns the following error (see The field XXX is required for numbering and must be defined!).
Having entered item category and saving any changes made, generates the next available item ID in the selected format:
