Recognition Algorithm Research on Query Language Based on Operator Precedence Grammar
Haoyin Lv, Tao Guo, Zhengqi Liu · 2016
The end of query is the composition of SQL statements, completed by using the graphical interface.Operator precedence grammar was combined with segmentation to identify query statement in graphic interface, this paper customized the semantic action and added correctness judgment "constraints( )", realized the composition of SQL and added fuzzy operator, multinational language library, process control, fault location and other language technology to make it more powerful, which was the expansion for SQL. IntroductionData management is not only to store and manage data, but also a system that focuses on information system implementation level.Language provided by DBMS is used to operate the database, and it is called Database Language.Structured Query Language (SQL) is now widely used.The supporting degree of DBMS to SQL is a key factor to evaluate whether it is successful, and an efficient and secure SQL compiler is one of the core and foundation of excellent databases.This paper used compilation technology and operator precedence grammar to compose query statement, customized relevant semantic actions, added correctness judgment"constraints( )", realized the composition of SQL.While fuzzy operator, multinational language library, process control, fault location and other language technology were added, and the identification and interpretation process from natural language (take Chinese as an example) to SQL language were realized.[1] Keywords and limits for different application systems are different and the priority relation is also complex for the mixed operation of logic statements.The main elements of words are keyword, logic operator, comparison operators, text and parentheses.Operator precedence grammar can effectively deal with the semantic recognition and construction and has the characteristic of error locating, multilanguage recognition, and automatic error correction of similar signs.[2] 2 The Lexical Recognition Process Analysis of Searching Statements Expression analysisExpression compromises the following two kinds of subclauses.Field comparison operator "content"Field comparison operator numerical valueThese two kinds of clauses are defined as text field and numerical value field. The contents of logic relationThe logic relation of subclauses of Where includes "and", "or" and "not".