英和和英

出典:『Wikipedia』 (2011/07/13 15:44 UTC 版)

英語による解説

引用

ERROL (an acronym for Entity Relationship Role Oriented Language; ) is a declarative database query and manipulation language for the Entity-relationship model (ERM). It is applicable to any data model on which ERM can be mapped, virtually any general purpose database data model. It is based on the capability of ER diagrams to be described accurately by simple Natural language (NL) sentences. A specification of a complex operation upon an ERM database can be described accurately by a complex and/or compound NL sentence constructed from the simple sentences describing the respective ER diagram. An ERROL expression mimics such NL sentence with one-to-one correspondence between ERROL subexpressions and NL subsentences: An ERROL expression can look like the corresponding NL sentence, or at least like a similar, equivalent one. This allows to write in ERROL very complex queries by simple conversion from their NL specifications. It also allows a straightforward checking of an ERROL expression meeting a complex NL specification. With such characteristics it can be a foundation for future Data management languages, more convenient for humans to use than existing languages which may need complex expressions even for moderately complex NL expressions (e.g., SQL; see Example below).