Two approximate operators for a data base query language: sounds-like and close-to

Approximate retrieval in a database of formatted data allows values that are close to those requested to be retrieved. Two approximate retrieval operators added to a structured query language are discussed. The two operators are sounds-like (SL) and close-to (CT). The SL operator is used to match two character string values by comparing their phonic sounds. The CT operator is used to select a subset of numeric data values that are relatively close to a given value. These two operators have been implemented and tested in a relational database environment called BDB. These extensions suffice to handle all data types and to allow the approximate retrieval to objects as well as attributes