Using SQL Function Blocks in XQuery Mapper

When you create a call to a SQL update function using XQuery Mapper, a SQL function block representing the function appears on the Mapper canvas. For example, consider the SQL block created for a ddtek:sql-update function call on the Products table:

Figure 376. Update Function Block

To map column name/value pairs, you first expand the SQL function block by double-clicking it. When you double-click a SQL function block, it expands to show the table name and each of the columns that make up the table:

Figure 377. Expanded SQL Functions Block

About the Output Port

All function blocks in Stylus Studio have an output port on the right side. In most cases, output from a function is mapped to either another function (a conditional expression, for example) or to a node on the target document.

Unlike most other XQuery source-target mappings, SQL functions do not generate any output - any changes specified by the XQuery are performed directly on the database. However, a link from the SQL function block's output port to the Set Target Document pane is required in order to commit the XQuery mapping to Stylus Studio. This link is completed automatically for you by Stylus Studio when you create SQL insert and update functions using drag and drop. If you create these functions using the short-cut menu (right-click the Mapper canvas and select Function Block > DataDirect XQuery...), you must create this link manually. The same is true for delete functions, which cannot be created using drag-and-drop.

Further, nothing is displayed in the Output window when you preview the XQuery - any changes resulting from the XQuery are reflected directly in the database.