@conference {CunhaOliveiraVisser:06a,
	title = {Type-safe Two-level Data Transformation},
	booktitle = {Proceedings of 14th International Symposium on Formal Methods - FM},
	series = {LNCS},
	volume = {4085},
	year = {2006},
	month = {August },
	pages = {284{\textendash}299},
	publisher = {Springer-Verlag},
	organization = {Springer-Verlag},
	address = {Hamilton, Ontario Canada},
	abstract = {<p>A two-level data transformation consists of a type-level transformation of a data format coupled with value-level transformations of data instances corresponding to that format. Examples of two-level data transformations include XML schema evolution coupled with document migration, and data mappings used for interoperability and persistence.<br />
We provide a formal treatment of two-level data transformations that is type-safe in the sense that the well-formedness of the value-level transformations with respect to the type-level transformation is guarded by a strong type system. We rely on various techniques for generic functional programming to implement the formalization in Haskell.<br />
The formalization addresses various two-level transformation scenarios, covering fully automated as well as user-driven transformations, and allowing transformations that are information-preserving or not. In each case, two-level transformations are disciplined by one-step transformation rules and type-level transformations induce value-level transformations. We demonstrate an example hierarchical-relational mapping and subsequent migration of relational data induced by hierarchical format evolution.</p>
},
	attachments = {https://haslab.uminho.pt/sites/default/files/alcino/files/10.1.1.106.738_1.pdf},
	author = {Alcino Cunha and Jos{\'e} Nuno Oliveira and Joost Visser},
	editor = {J. Misra and T. Nipkow and E. Sekerinski}
}