Test Expressions
- Last UpdatedMar 27, 2024
- 2 minute read
Expressions are tested using the Preview tab.
The tab is used to test whether is an XPath expression is valid and returns data which conforms to the schematic element attribute type that the mapping would be applied to.
The tab is also used to preview the results that would be generated in the database for the elements that an expression would be applied to in a selected drawing, so that it can be checked that the expected result of applying the expression would be achieved.
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To test an expression, enter or select it on the Build tab.
The Expression pane at the bottom of the Preview tab is the same as that on the Build tab and displays the expression that was selected or entered on that tab.
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To select the drawing against which the expression is to be tested, click the ... option. Select the drawing from the Open dialog that is then displayed. The default location is specified on the User Options dialog (refer to File Locations).
The selected drawing and its file path, file format, file version and source system are then displayed in the Source File field in the format:
<source system>/<file format>/<file version> : <filepath>
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Click Evaluate. If the expression is invalid, and error message is displayed.
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The Status: symbol, which is also displayed on the Build tab, then indicates the validity of the expression.
A green tick indicates that the expression has been checked and is valid. A red cross indicates that the expression has been checked and is not valid.
A white question mark within a blue circle indicates that the expression has not yet been validated. If the expression is changed after it has been validated, the Status: symbol reverts to this symbol.
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For each of the elements that the expression would be applied to were the selected diagram to be imported, the source element type is displayed in the TYPE column, the tag of the element in the drawing is displayed in the Tag field, and the attribute value would result from the application of the expression is displayed in the Result field.
