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首页> 外国专利> SUBSTITUTING PARAMETER MARKERS FOR LITERALS IN A DATABASE QUERY LANGUAGE STATEMENT TO PROMOTE REUSE OF PREVIOUSLY GENERATED ACCESS PLANS

SUBSTITUTING PARAMETER MARKERS FOR LITERALS IN A DATABASE QUERY LANGUAGE STATEMENT TO PROMOTE REUSE OF PREVIOUSLY GENERATED ACCESS PLANS

机译：在数据库查询语言声明中将参数的标记替换为文学，以促进重复使用之前生成的访问计划

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摘要

A method, computer program product and computing device for promoting reuseofpreviouslygenerated access plans in a relational DBMS are disclosed. SQL statementscontaining literals areamended so as to substitute a parameter marker for each literal. Amendedstatements are providedto the DBMS along with parameters comprising the substituted literals and asubstitution indicatorindicating that the substitution has been performed. The DBMS assesses thesoundness of thesubstitutions that are performed. Soundness may be measured in terms of thesemantic correctnessof the amended statement and the likelihood that the literal substitution willimprove DBMSefficiency. If a substitution is unsound, the DBMS may obtain and optimize(i.e. select an accessplan for) the original version of the amended SQL statement. Otherwise, theamended statement isoptimized. Advantageously, SQL statements originally differing only in thevalue of one or moreliterals may become functionally equivalent, and the reuse of cached,previously generated accessplans is thus promoted. Improvements in DBMS efficiency may thus be achieved.
机译：一种促进重用的方法，计算机程序产品和计算设备以前公开了在关系DBMS中生成的访问计划。 SQL语句包含文字是修改，以便为每个文字替换参数标记。已修改提供陈述DBMS以及包含替换文字和参数的参数替代指标表示已执行替换。 DBMS评估的健全性执行的替换。健全性可以根据语义正确性修改后的陈述的含义以及字面替换将出现的可能性改善DBMS效率。如果替换不正确，则DBMS可以获取并优化（即选择一个访问权限计划）修改后的SQL语句的原始版本。否则，修改后的声明是优化。有利的是，SQL语句原本仅在一个或多个的值文字可能在功能上等效，并且缓存的重用，先前生成的访问因此促进了计划。因此可以实现DBMS效率的提高。

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