Customizer's Guide > Merging Data from Other Sources > Query Definitions
  
Query Definitions
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The capability to merge data is deprecated and not an encouraged best practice supported by PTC.
A query refers to a query definition. The query definition is one of many definitions stored in a data merge (xml) configuration file. A query definition consists of a UI component and a formal definition.
The query definition UI component includes:
The name of the query definition. This name links a document's query to a query definition.
The parameters that must be passed to the query. The parameters must be given values at the time of inserting a query.
The query result type: document content, or name-value pairs.
A representative top level tag for quick context verification if document content is returned.
The query definition formal definition includes:
A source stage. This may be any program that generates a DOM node. The actual source may be a database, a file, a URL, or some external process. The program is responsible for presenting the result as a node, perhaps using some simple markup to represent name value pairs.
One or more transformation stages. These stages take a DOM node as input and generates a new DOM node as output.
A description of the order in which the stages are to be applied, starting with the source.
For each stage, a mapping of UI parameters to actual parameters for the stage.