Natural Language Database Updates

Although a great deal of research effort has been expended in support of natural language (NL) database querying, little effort has gone to NL database update. One reason for this state of affairs is that in NL querying, one can tie nouns and stative verbs in the query to database objects (relation names, attributes and domain values). In many cases this correspondence seems sufficient to interpret NL queries. NL update seems to require database counterparts for active verbs, such as "hire," "schedule" and "enroll," rather than for stative entities. There seem to be no natural candidates to fill this role. We suggest a database counterpart for active verbs, which we call verbsraphs. The verbgraphs may be used to support NL update. A verbgraph is a structure for representing the various database changes that a given verb might describe. In addition to describing the variants of a verb, they may be used to disamblguate the update command. Other possible uses of verbgraphs include, specification of defaults, prompting of the user to guide but not dictate user interaction and enforcing a variety of types of database integrity constraints. I. MOTIVIATION AND PROBLEM STATF~NT We want to support natural language interface for all aspects of database manipulation. English and English-like query systems already exist, such as ROBOT[Ha77], TQA[Da78], LUNAR[W076] and those described by Kaplan[Ka79], Walker[Wa78] and Waltz [Wz75]. We propose to extend natural language interac$ion to include data modification (insert, delete, modify) rather than simply data extraction. The desirability and unavailability of natural language database modification has been noted by Wiederhold, et al.[Wi81]. Database systems currently do not contain structures for explicit modelling of real world changes. A state of a database (OB) is meant to represent a state of a portion of the real world. This research is partially supported by NSF grants IST-79-18264 and ENG-79-07794. We refer to the abstract description of the portion of the real world being modelled as the semantic data descri~tlo n (SDD). A SDD indicates a set of real world states (RWS) of interest, a DB definition gives a set of allowable database states (DBS). The correspondence between the SDD and the DB definition induces connections between DB states and real world states. The situation is diagrammed in Figure i.