WordNet (2005) defines the noun file or datafile as "a set of related records (either written or electronic) kept together", while the verb file or register is defined "record in a public office or in a court of law) "file for divorce"; "file a complaint" " and the verb file, file away is defined "place in a container for keeping records "File these bills, please" "
By database hosts are single databases termed files. In Dialog's catalog of databases are the single databases termed files. (File 7 is, for example, Social Scisearch").
The classical database technology (as used, for example, by Dialog) have a primary "linear" or sequential file" and a number of secondary "inverted files". From the primary file are taken data with information about the identification number(s) of the record(s) to which they belong as well as the field in the record and the position within the field. These data a put in different inverted files, e.g. author field, title field, corporate source field, journal name field and so on.
Boolean searches are performed in the inverted files and search sets are formed with identification numbers for records in the linear file. By commands for display or print are records in the linear file retrieved and displayed in the selected format. This technique is advanced but puts some restrictions on how searches can be done.
Multiple files may be searched at the same time. Dialog, for example, introduced its onesearch facility in October 1987.