Abstract: A database contains data items with which various index terms 40 are associated. The database arrangement maintains information about relationships between the index terms, there being a relationship between any two index terms which are both associated with a data item in common. This allows a user to be provided with a graphical representation (see drawing) of the relationship between index terms. When index terms are used to interrogate the database, the user is provided with a graphical display of that part 50 of the network relationships which includes the requested index term (e.g. Product 1) and all other index terms with which that terms has a relationship. This assists a user in refining a search strategy and thus improves the quality of information retrieval from the database.