Using PHP 4s DOM XML Functions to Create XML Files from SQL Data
By Tony Marston2005-04-04
Adding optional attributes
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It may sometimes be necessary to include additional information for an element with the XML data, and this can be done in the form of attributes. An attribute has a name and a value, and any number of attributes can be added to an element. This must be done by using the '->set_attribute' method immediately after the '->append_child' method and before any '->create_text_node' method, as shown in the following code snippet:
$child = $doc->create_element($fieldname);These attribute values will then appear within the element's start tag, as follows:
$child = $outer->append_child($child);
$child->set_attribute('attr1', 'attrval1');
$child->set_attribute('attr2', 'attrval2');
$value = $doc->create_text_node($fieldvalue);
$value = $child->append_child($value);
<?xml version="1.0"?>Note that you can insert attributes for row elements as well as column elements.
<root>
<some_table>
<column1 attr1="attrval1" attr2="attrval2">value1</column1>
<column2 attr1="attrval1" attr2="attrval2">value2</column2>
<column3 attr1="attrval1" attr2="attrval2">value3</column3>
</some_table>
</root>
In my own application I use attribute values to specify the size of each column, so that it does not have to be hard-coded within the XSL file. For multi-line columns I pass values for both 'rows' and 'cols'.
I also use attributes to include any error messages. All error messages get inserted to an array called $errors where the key is the fieldname and the value is the message. The code to insert the error message into the XML document as an attribute of the field which generated the error is as simple as this:
if (isset($errors[$fieldname])) {
$child->set_attribute("error", $errors[$fieldname]);
} // if
Tutorial Pages:
» Intended Audience
» Prerequisites
» Multiple occurrences of a single table
» A One-to-Many relationship
» Adding optional attributes
» Using Multi-Byte Characters
» Conclusion
» References
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