Object oriented query path expression to relational outer join translator method, system, and article of manufacture, and computer program product

摘要

Provided is an object oriented query path expression to relational outer join translator. A path expression, comprising a navigation path through a relationship in a schema, in an object oriented query is translated to a relational database outer join by analyzing each path expression defined in each level of the object oriented query, and by identifying each path expression which can be a candidate for a translation to an outer join. A quantifier is created for each path expression. A translation of the object oriented query to a relational query is then completed. An optimization may also be performed on the grouped quantifiers. After the optimization, an inner join is generated for each quantifier which remains a candidate for a translation to an inner join, and an outer join is generated for each quantifier which remains a candidate for a translation to an outer join.