Database query system

摘要: A database query system includes a assitant that permits the user to enter only queries are both syntactically and semantically valid (and can be processed by an SQL generator produce SQL). Through use of dialogue boxes, enters in intermediate English-like language which is easily understood user. expert monitors as it being built, using information about structure database, prevents from building incorrect disallowing choices boxes would create queries. An also provided uses set transformations pattern substitutions convert into correct query. The represent complex while at same time easy understand. designed converted In addition assistant generator, administrative facility allows administrator add conceptual layer underlying making easier for database. This may contain alternate names columns tables, paths specifying standard joins, definitions virtual tables columns, limitations on access.