QGraph is implemented in Proximity, an open source system for relational knowledge discovery. Proximity represents queries in an XML format described in Appendix B, XML Representation. Although you can create queries by editing the XML file, Proximity provides a Query Editor that lets you work with queries using a more intuitive graphical representation similar to that used in this guide. You can also edit, save, validate, and execute queries directly from the Proximity Query Editor. This chapter provides a brief overview of how to use the Proximity Query Editor. See the Proximity Tutorial for more information on using the Query Editor and on creating and executing queries in Proximity.
The Proximity Query Editor is available from the Proximity Database Browser, a browser-based interface to Proximity’s functionality. To access the Query Editor, select New Query from the Query menu of the Proximity Database Browser, shown below.
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Other options in the Query menu apply to existing query files:
This chapter describes how to use the Query Editor to create, edit, save, and execute QGraph queries. See the Proximity Tutorial for information on other methods of executing queries in Proximity.
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defining one or more vertices
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defining edges linking those vertices
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adding any conditions and annotations to the vertices and edges
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defining any subqueries
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adding any constraints between separate query elements
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adding any database update (new link) specifications
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providing a name and description for the query
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making sure the query is valid
A query can be as simple as a single vertex. Therefore, with the exception of defining at least one vertex and validating the query, all of these steps are optional. Invalid queries will not execute and may not be correctly saved—we recommend that you check the status list for errors before executing or saving a query. The Query Editor imposes no ordering on these steps.