Spreadsheet As a Relational Database Engine

摘要

Spreadsheets are among the most commonly used applications for data management and analysis. Perhaps they are even among the most widely used computer applications of all kinds. However, the spreadsheet paradigm of computation still lacks sufficient analysis. In this paper we demonstrate that a spreadsheet can play the role of a relational database engine, without any use of macros or built-in programming languages, merely by utilizing spreadsheet formulas. We achieve that by implementing all operators of relational algebra by means of spreadsheet functions. Given a definition of a database in SQL, it is therefore possible to construct a spreadsheet workbook with empty worksheets for data tables and worksheets filled with formulas for queries. From then on, when the user enters, alters or deletes data in the data worksheets, the formulas in query worksheets automatically compute the actual results of the queries. Thus, the spreadsheet serves as data storage and executes SQL queries, and therefore acts as a relational database engine. The paper is based on Microsoft Excel (TM), but our constructions work in other spreadsheet systems, too. We present a number of performance tests conducted in the beta version of Excel 2010. Their conclusion is that the performance is sufficient for a desktop database with a couple thousand rows.