Query Parameters

Query Parameters

When you are working with SQL queries to generate the data for a Zen table, you sometimes need to provide values for query input parameters, defined as ? characters within the query. To do this, use <parameter> elements within the <tablePane> element. <radioSet>, <select>, <dataListBox>, <dataCombo>, <repeatingGroup>, and <multiSelectSet> can also contain <parameter> elements to support queries.

When you supply a query directly, as with a sql attribute, each <parameter> element substitutes for one ? in the query syntax, in order from left to right, even if the values are the same. For example:

<tablePane id="table"
           sql="SELECT ID,Name FROM MyApp.Employees
                WHERE Name %STARTSWITH ? AND 
                ((Salary &lt; ?) OR (TotalCompensation &lt; ?)) 
                ORDER BY Name"
           >
     <parameter value="Z"/>
     <parameter value="100000"/>
     <parameter value="100000"/>
</tablePane>

The “Data Sources” section in this chapter provides several other examples of how to use the <parameter> element, including the following class query example. Here each <parameter> element substitutes for one argument in the class query:

<tablePane id="table"
           queryClass="MyApp.Employee"
           queryName="ListEmployees">
    <parameter value="Sales"/>
    <parameter value="NEW YORK"/>
</tablePane>

When you work with %ZEN.Component.tablePaneOpens in a new tab programmatically, If you are using one of the classes <radioSet>, <select>, or <multiSelectSet>, which do not implement the setProperty, you must first set an id for the parameter:

<parameter value="Sales" id="param1"/>

The following example changes the value of the first parameter to Finance, re-executes the query on the server, and updates the contents of the tablePane to display the new results:

 ClientMethod changeParams() [ Language = javascript ]
 {
     // find the tablePane component
     var table = zenPage.getComponentById('table');
     var param1 = zenPage.getComponentById("p1");
     param1.value='Finance';
     table.executeQuery();
 }