Translation Of DDL And DML For Constructing Flexible Schemas In Saas Applications

Multi-tenancy is one of the most important features in Software as a Service(SaaS). In order to reduce cost, SaaS service vendors typically implement multi-tenant enabled database on top of conventional SQL database, and Universal Table is one of the most commonly used implementation technique. The key idea is to map all tenant data into one single table. At the application level, such a scheme-mapping is implemented by translating SQL statements. Previously, researchers have introduce methods to the translation of SQL query. In this work, we extend previous work by proposing a method that support the translation of full SQL syntax, including both data manipulation language (DML) and data definition language (DDL). Our method is based on syntax-directed translation on the context-free grammar of full SQL syntax. We have implemented our method as an automatic translation tool based on the ANTLR framework. In order to evaluate the effectiveness and efficiency of our method, we conduct an empirical study using the TPC-C benchmark. The results show that our method is scalable to the number of tenants and the size of database.