Translation of the Data Flow Query Language for the Multimodel, MultibackendDatabase System

摘要

This thesis involved the design and translation of the Data Flow Query Language(DFQL) for the Multi-Lingual, Multi-Backend Database System (MDBS). The MDBS is a database system that can effectively support multiple data models and their corresponding data manipulation languages. The problem was the MDBS interfaces are text-based, and not very user-friendly. The approach taken to solve this interface problem was to design and translate the DFQL for implementation on the MDBS. DFQL was designed to improve and extend SQL, the data manipulation language associated with the relational data model. It uses a graphical interface based on the data flow paradigm. This translation would extend the MDBS by allowing a graphical interface to be implemented, whereas currently a user can only access the system with text-based interfaces. The result of this thesis is the development of the DFQL to ABDL translator. The subsequent implementation of this translator on the MDBS would be a user-oriented enhancement to the current system. In addition, further improvements to the MDBS should be made, such as allowing the use of additional data types (currently constrained to string and integer) and the ability to create views. These changes would allow all the benefits from DFQL, such as orthogonality, language extensibility and incremental querying to be achieved and made available to the user.