Recommendation systems have become very popular but most recommendation methods are ‘hard-wired’ into the system making experimentation with and implementation of new recommendation paradigms cumbersome. In this paper, we propose FlexRecs, a framework that decouples the definition of a recommendation process
from its execution and supports flexible recommendations over structured data. In FlexRecs, a recommendation approach can be
defined declaratively as a high-level parameterized workflow comprising
traditional relational operators and new operators that generate or combine recommendations. We describe a prototype flexible recommendation engine that realizes the proposed framework and we present example workflows and experimental results that show its potential for capturing multiple, existing or novel, recommendations
easily and having a flexible recommendation system that combines extensibility with reasonable performance.
