A COST-BASED APPROACH FOR CONVERTING RELATIONAL SCHEMAS TO XML

ABSTRACT: Converting relational database schemas to XML schemas is important as applications originally written to manipulate relational data are converted to XML-enabled applications. An important challenge is determining good XML schemas from existing relational schemas, so that applications may be migrated to use XML. In this paper, we propose a general algorithm for converting relational schemas to XML schemas that returns the optimal XML encoding exhibiting no redundancy and respects user constraints on the resulting XML schema. Previous conversion algorithms required the user to specify a complete mapping or did not allow user-specified constraints. The conversion is performed based on a user-supplied cost function. In this paper, the cost measure is based on the space efficiency of the XML encoding as a metric for measuring the XML schema's desirability. The result is a fully automatic system for migrating relational schemas to XML schemas while respecting conversion constraints