NIAGARA Client
In the text area in the Query Input group you can write compose your query (either XML-QL or SEQL ). Press Execute Query to get results. In the Query Result group you will see the results in tree form (JTree). The get next button is used to obtain the results in batches.
You can pose queries on the data so far.
If you press the Query Button you will see a simple interface for constructing XML-QL queries.
To choose the dtd on which to base a query press the Choose DTD button. A list box will appear allowing you to choose one or more dtd's. The dtd is displayed in tree format and features like sets and choices are not yet incorporated in the interface. The idea is to quickly generate a query body and then probably fine tune the query by hand.
By right-clicking on an element the element is projected. Double clicking causes a dialog to appear where predicates can be specified. The OK button generates an XML-QL Query and returns to the main frame.
Joins are performed using drag and drop. This feature is still a little problematic in the applet: One has to make sure that before performing the drag and drop the target element is selected. We will try to fix this problem. The application client does not have this problem.
By pressing the Search button in the main frame you get an interface which allows you to generate search engine queries.
The usage is similar to the XML Query Interface with the excpetion that there are containment operators and there are no joins.
To construct a continuous query, you may first construct a common XML-QL query as illustrated above using the GUI. Then you click on the install trigger button. You will see following window to let you specify the values of the time property of your continuous queries.
All the values in this windows are optional. Unless you type in some values, default values will be used.
After you finish above setting, or if you don't want to change the default setting, click on Ok, you will see time information and trigger action is added to your XML-QL query automatically.
You can then click on Execute query to install the continuous query into the system.
Warning: Currently your continuous queries will not be stored persistently in the system . Thus once the system is down, your installed continuous queries will be lost. :-(
Have FUN :-)
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