With the advent of Big Data, data integration is very important topic in the heterogeneous bioinformatics landscape. This book starts off with the current state of biological pathway databases in general, and in particular, plant pathway databases. We explore different models to interface with the various stakeholders of biological data repositories. We discuss the potential use of XML as a repository for information integration, downstream processing, and data. Having explored different alternatives, we build up our own comprehensive knowledge repository for plant metabolic networks. A public website was built to make information available for ad-hoc users. In addition, a dedicated API (MetNetAPI: is provided to accommodate bioinformaticians and software developers who wish to build advanced applications on top of the warehouse. Integrated databases are only useful when they can be synchronized with their respective external sources. We've created a framework for a systematic approach to integration. This work thus provides a roadmap to current and future biological database projects