GQL和SQL/PGQ：理论模型与表达能力
GQL and SQL/PGQ: Theoretical Models and Expressive Power
AI总结：
研究SQL/PGQ和GQL，定义Core GQL和Core PGQ核心语言，通过理论分析明确语言差异、不足及扩展必要性，实验研究表明现有变通方法不实用，凸显语言设计改进必要。
摘要：
SQL/PGQ和GQL是查询属性图的国际标准，前者用SQL查询属性图关系表示，后者是图数据库独立语言。虽有语言摘要，但缺乏如关系代数等形式模型。本文对其进行形式化研究，定义核心语言，分析表达能力等，实验表明现有变通方法不实用，强调改进语言设计的必要性。
英文摘要：
SQL/PGQ and GQL are very recent international standards for querying property graphs: SQL/PGQ specifies how to query relational representations of property graphs in SQL, while GQL is a standalone language for graph databases. The rapid industrial development of these standards left the academic community trailing in its wake. While digests of the languages have appeared, we do not yet have concise foundational models like relational algebra and calculus for relational databases that enable the formal study of languages, including their expressiveness and limitations. At the same time, work on the next versions of the standards has already begun, to address the perceived limitations of their first versions. Motivated by this, we initiate a formal study of SQL/PGQ and GQL, concentrating on their concise formal model and expressiveness. For the former, we define simple core languages -- Core GQL and Core PGQ -- that capture the essence of the new standards, are amenable to theoretical analysis, and fully clarify the difference between PGQ's bottom up evaluation versus GQL's linear, or pipelined approach. Equipped with these models, we both confirm the necessity to extend the language to fill in the expressiveness gaps and identify the source of these deficiencies. We complement our theoretical analysis with an experimental study, demonstrating that existing workarounds in full GQL and PGQ are impractical which further underscores the necessity to correct deficiencies in the language design.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
