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Building Queries and Data Views

Data View Builder Overview

The Data View Builder is a GUI-based tool for designing and generating XML-based queries (in W3C XQuery syntax). You can then run the queries against heterogeneous data sources to retrieve information. The Builder provides a pictorial, drag-and-drop mapping approach to query design and construction. Using the Data View Builder frees you from having to focus on the intricacies of query languages so that you can give full attention to information design, the conceptual synthesis of information coming from multiple sources, and the content and shape of the information you want in the query result or target. In this way, you can to directly access distributed, heterogeneous data sources as "integrated logical views."

Advantages of the Data View Builder

The Data View Builder lets you create queries using an intuitive, drag-and-drop mapping strategy that frees you from having to grapple with the details of query languages. The XML schema representations and mappings of source and target data are packaged and saved as a project. Users can retrieve the full picture of the query complete with source schemas and target mappings thereby getting access to the query in the context of a design model. Queries can also be stored as data views that can be configured as data sources themselves in Liquid Data and re-used to create nested subqueries; "views on views" of information.

How the Data View Builder Works

In the Data View Builder, you drag and drop elements and attributes among XML schema representations of data sources to create source conditions (joins, unions, and so on). The default source condition is a join (that uses an equality function); you can also use the more complex functions provided in the Builder toolbar. You also map source to target schema elements and attributes to shape the structure of the query result. As you build up the query with drag-and-drop modeling, the Builder is constructing the query in the background in valid, well-formed XQuery syntax. An "Optimize" view is also available for adding optimization hints to a query to improve performance. When you are ready to run a query, you can switch to the Builder "Test" view, see the generated XQuery for the current query, run it and see the query result in XML.

The Data View Builder provides hierarchical tree XML schema representations of all data sources configured in Liquid Data, regardless of the data source type. Once a data source has been configured in Liquid Data using the WebLogic Server Administration Console (see the Liquid Data Administration Guide), it shows up in the Builder toolbar where you can access its XML schema representation. The structure of the data stored in relational databases, Web services, application views, data views, and XML files themselves are all represented as XML schemas in the Data View Builder. By creating this coherent picture of heterogeneous data sources as XML schemas, Data View Builder makes it easy for you to browse and map data elements and attributes among different types of data sources.