Definition[]
A query is
| “ | (1) A user request for additional or amplifying information regarding information received through some means. (2) In data communications, the process by which a master station (or mainframe or boss computer) asks a slave station to identify itself and tell its status (i.e., is it busy, alive, OK, waiting, etc.). (3) A data structure consisting of one or more search criteria and, associated with each search criteria, a set of actions. Search criteria are Boolean functions whose terms consist of metadata attributes (e.g., data of last modification, size), operators on those attributes (e.g., size <12000), or evaluation functions that operate on a data instance (e.g., key word found{China}). The set of actions associated with each search criteria indicates what the user wished to occur whenever the criteria evaluates to TRUE (e.g., retrieve the data instance, provide the user with a pointer to the data instance, provide the user with the metadata associated with the data instance, etc.).[1] | ” |