Hi Roger, How about using a “relational” structure, as below? It avoids both the duplication inherent in the “flat” and the depth of structure of the “fat”. It is easy enough to transform to either of the other two structures. John <document> <states> <state ref="IA"> <name>Iowa</name> ... </state> <state ref="NY"> <name>New York</name> ... </state> ... </states> <citys> <city ref="234123"> <name>Davenport</name> <state-ref>IA</state-ref> <pop>382630</pop> ... </city> <city ref="3828"> <name>Cedar Rapids</name> <state-ref>IA</state-ref> ... </city> ... </citys> <streets> <street ref="234235"> <name>"Arlington Court"</name> <zip>IA 52803</zip> <city-ref>234123</city-ref> </street> ... </streets> <houses> <house ref="3fsdh89"> <street-ref>234235</street-ref> <street-number>1009</street-number> <style>Ranch</style> <porch>open</porch> <year-built>1951</year-built> <square-feet>1700</square-feet> ... </house> <house ref=”xyix3sf”> <street-ref>234235</street-ref> <street-number>1008</street-number> <style>Ranch</style> <porch>closed</porch> <year-built>1955</year-built> <square-feet>1850</square-feet> </house> ... </houses> <document> From: Costello, Roger L. [mailto:costello@mitre.org] Hi Folks, The flat design is about creating XML documents that consist of a long series of standalone components:
A component in the document can be combined with other data (mashup):
Let’s take a concrete example to compare the flat design versus the fat design. Here is a flat design: <Iowa> The document consists of a long series of standalone <house> components. Any of those <house> components could be mashed-up with other data, e.g., mashup a <house> component with a <GPS> component. Here is a fat design: <Iowa> <street-number>1009</style> <street-number>1008</style> The flat design and the fat design are radically different! In the fat design the houses have been grouped into streets and the streets have been grouped into cities. The street name data has been removed from each <house> and also the city name data has been removed from each <house>. Consequently, each <house> is no longer a standalone component. House data is now fragmented, scattered over the document. The ability to do mashups has been lost (or, at least, greatly hampered). The fat design has normalized the data and, as I argued in my last message: Normalization is horrible for data exchange formats. It’s best to exchange the data in the flat design. Consumers can transform it into the fat design, if needed. Recommendation: When designing a data exchange format create a flat design. Comments? /Roger |
