The List_Tree - an innovative solution to customer portfolio representation

The scale of BT's operations necessitates the use of very large scale compu ting systems, and the storage and management of large volumes of data. Cust omer product portfolios are an important form of data which can be difficul t to store in a space efficient way. The difficulties arise from the inhere ntly structured form of product portfolios, and the fact that they change o ver time as customers add or remove products. This paper introduces a new d ata-modelling abstraction called the List_Tree. It has been designed specif ically to support the efficient storage and manipulation of customer produc t portfolios, but may also prove useful in other applications with similar general requirements.