METU Object-Oriented DBMS

Abstract

METU Object-Oriented DBMS¹ includes the implementation of a database kernel, an object-oriented SQL-like language and a graphical user interface. Kernel functions are divided between a SQL Interpreter and a C++ compiler. Thus the interpretation of functions are avoided increasing the efficiency of the system. The compiled by C++ functions are used by the system through the Function Manager. The system is realized on Exodus Storage Manager (ESM), thus exploiting some of the kernel functions readily provided by ESM. The additional functions provided by the MOOD kernel are the optimization and interpretation of SQL statements, dynamic linking of functions, and catalog management.

An original query optimization strategy based on the object-oriented features of the language is developed. For this purpose formulas for the selectivity of a path expression, and for the cost of forward and backward path traversals are derived, and join sizes are estimated. New strategies for ordering the joins and path expressions are also developed.

A graphical user interface, namely MoodView is implemented on the MOOD kernel. MoodView provides the database programmer with tools and functionalities for every phase of OODBMS application development. Current version of MoodView allows a database user to design, browse, and modify database schema interactively. MoodView can automatically generate graphical displays for complex and multimedia database objects which can be updated through the object browser. Furthermore, a database administration tool, a full screen text-editor, a SQL based query manager, and a graphical indexing tool for the spatial data, i.e., R Trees are also implemented.