The network IVR can manage lists of values. These can be used as a type of database. Every record contains up to 4 values.
A record, that represents a customer, could contain the Customer Number, Name and Telephone Number.
Note - that what the records actually contain - is down to your design and choice.
Lists are created by accessing the function System Settings - Lists in the main menu. You will see a view of the existing lists. Use New to create a new list. Use Edit and the Entries tab to see the data contained in the list. A detailled description can be found in the Lists section in the administration chapter.
The use of lists and variables is explained in the example here: IVR Example Program 2 - Lists and Variables