Is SchemaFree Navigationless Processing More Powerful Navigational Processing?
In spite of most XQuery developers and book authors’ belief that XQuery is nonprocedural, user navigational processing used by it is procedural requiring step-by-step navigational instructions by the user. This limits its processing capability. On the other hand, navigationless processing is nonprocedural requiring no step-by-step navigation or knowledge of the structure by the user.
In the beginning with third and fourth generation products, procedural languages were used for complex and non standard problems while nonprocedural languages were used for simple and standard solutions which are more likely to be covered by nonprocedural languages. With database hierarchical navigation, this is not true. Procedural navigation does give the user complete control, but does require very complex processing for queries involving multiple hierarchical paths making its use impractical. It also happens that databases with their more fixed hierarchical structure can be navigated automatically using nonprocedural languages like SQL. This can allow nonprocedural navigationless SQL to automatically navigate the most complex multipath database XML transparently.
There are many new capabilities that come along with this nonprocedural navigationless capability. For example, the query user can be nontechnical and does not need to know the structure to specify the query. Following these capabilities a step further, this means the user having no knowledge of the structure must be able to unknowingly reference multiple pathways in order to process a query with no knowledge of its structure, no easy capability today. Processing multipath queries also means that the customer’s value of their data is greatly increased automatically and dynamically. This is because of the goldmine of natural hierarchical semantics existing naturally between the structure’s pathways being accessed is being automatically utilized to process this query in a much more powerful way making this another advanced capability. This automatic processing also means that the hierarchical processing is being handled correctly and can be performed interactively. And finally, by opening up the entire structure for unlimited query access, the number of possible query structures for a given structure becomes almost unlimited which also increases the value of the customer’s data. This also means that as new pathways are added to the hierarchical data structure over time, the number of new possible queries grows many times over. This natural structure definition reuse is a powerful characteristic of hierarchical structures that can now be utilized by this multipath navigationless query capability known today as schema free processing.SQL with its navigationless processing is in a position today to support this advanced multipath processing of hierarchical structures.