This page briefly introduces the features of EML (E-model Language) and the E-model system.
EML is an E-model data query language extending the SQL-89 standard with enhanced features: (1) unstructured query, (2) semantic query expansion, (3) temporal query, (4) ranked ordering, (5) path query, and (6) natural join.
The EML grammar is written in Backus–Naur Form using Gold Parsing System. Complete one will be released after publication.
EML interpreter converts the statement writting in EML into SQL statements. The current E-model system prototype is developed on top of relational database as pure SQL statements. Thus EML interprets EML codes into SQL statements. An interpreter is the next step after parsing and it is developed based on Astudillo C++ Engine.
An E-model database system is built atop of relational database. Its full functions are implemented using hundreds of SQL procedures and functions. The idea is when a database system adds the E-model database to existing databases, then a user can query the database in the mixture of structured queries and E-model queries. EML implements such ideas with an extend SQL language to support both structured and unstructured queries with various feature additions.
EML BNF is an extension of an ad hoc version of SQL 89 for Gold parser. ! --------------------------------------------------------------------------------+++ ! E-model language (EML) ! ! An E-model prototype is implemented on top of relational database. ! Its full functions are implemented using hundreds of SQL procedures ! and functions. The idea is when a database system adds the E-model ! database to existing databases, then a user can query the database !