I like the idea of saving the data as an XML file. There is a web site www.rqml.org, which has a proposed format. A format like RDF (Resource Description Framework) would probably be more flexible, though. RDF allows you to encode statements with subject, attribute, and value. It's a format on top of XML, so XML tools can be used. There's also development effort in progress to create RDF databases.
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I like the idea of saving the data as an XML file. There is a web site www.rqml.org, which has a proposed format. A format like RDF (Resource Description Framework) would probably be more flexible, though. RDF allows you to encode statements with subject, attribute, and value. It's a format on top of XML, so XML tools can be used. There's also development effort in progress to create RDF databases.