Schematron Validation¶

Version: 2.1.0

Note: The standalone Schematron editor tab has been retired. .sch files open as ordinary editor tabs in the Unified Shell, and validation runs in the Validation activity panel. The Schematron tools — rule check, templates, tester, visual builder, documentation, and the validation report — sit in the Validation panel's ⋮ menu → Schematron Tools. The capabilities below are unchanged; they are reached through the shell rather than a dedicated sidebar tab.

Schematron lets you create custom validation rules that go beyond what XSD schemas can check. It's perfect for validating business rules and data relationships.

Overview¶

While XSD schemas check the structure of your XML (which elements can appear where), Schematron checks the content and relationships:

XSD Checks	Schematron Checks
Element names	Data values
Element order	Field relationships
Required fields	Business rules
Data types	Conditional requirements

Example Rules¶

"If status is 'approved', an approval date must be present"
"The total must equal the sum of all line items"
"Each ID must be unique in the document"

Schematron files use the shell's single-row editor toolbar. Related actions sit in split buttons with a visible ▾ arrow menu; see Unified Shell - Toolbar for the full reference.

With a .sch file active, the relevant actions are:

Button	Shortcut	Description
New	Ctrl+N	Open the guided New File dialog (includes Schematron)
Open	Ctrl+O	Open an existing file
Save ▾	Ctrl+S	Save the current file; the arrow menu holds Save As… (Ctrl+Shift+S) and Save All
Undo / Redo	Ctrl+Z / Ctrl+Y	Undo / redo the last change (icon buttons)
Format ▾	Shift+Alt+F	Pretty-print the file. (Note: Ctrl+Shift+F opens Find in Files, not document search.)
Validate	F8	Check that the Schematron file is well-formed XML (the result appears in the Validation panel's PROBLEMS list). Use Check Rules for a deeper rule-level inspection
Query Console	Ctrl+Shift+X	Toggle the bottom XPath/XQuery console — the place to try out rule expressions

Rule templates, the tester, the visual builder, and Check Rules are reached through the Validation activity panel (see Schematron Tools in the Unified Shell).

Editing Schematron Files¶

A .sch (or .schematron) file opens as a normal file tab in the shell's editor — there is no separate Schematron editor. The document is detected as Schematron by its namespace (http://purl.oclc.org/dsdl/schematron), which enables:

Syntax highlighting and IntelliSense for Schematron elements (pattern, rule, assert, report, …) in the Text view
A Tree view of the file's patterns, rules, and assertions (switch views in the editor toolbar)
Well-formedness checking with Validate (F8); rule-level problems are found with Check Rules (see below)

To create a new Schematron file, use New (Ctrl+N) and pick the Schematron template in the New File dialog. Ready-made rule snippets are inserted from Rule Templates.

Testing XPath Expressions¶

To try out a rule's context or test expression, open the XML document you want to check and press Ctrl+Shift+X to show the Query Console. It evaluates XPath (and XQuery) against the active document and lists the matching nodes, so you can refine an expression before putting it into a rule. See Query Console in the Unified Shell guide.

Schematron Tools in the Unified Shell¶

The Validation activity panel offers a set of Schematron tools in its ⋮ menu under Schematron Tools. Each one opens as a closable tool tab in the editor area:

Tool	What It Does
Rule Templates	Insert ready-made Schematron rule patterns into the active editor
Tester	Run the rules against an XML file (pre-loads the bound Schematron, if any)
Rule Builder	Build rules visually
Check Rules	Inspect the Schematron file itself for problems
Documentation	Generate documentation for the Schematron file
Validation Report	Open a detailed report of the last Schematron validation run

Check Rules¶

Check Rules runs an error detector over your Schematron file and shows the issues it finds in a categorised table, so you can fix mistakes in the rules before relying on them. Issues are grouped into categories:

Category	Examples
XML syntax	Malformed XML, unclosed tags
Structural	Missing or misplaced patterns, rules, or assertions
XPath	Invalid XPath expressions in contexts or tests
Semantic	Rules that can never match, or contradictory conditions
Best practice	Style and maintainability suggestions

Documentation¶

Documentation opens the Schematron documentation generator, which produces readable documentation describing the patterns, rules, and assertions in your Schematron file.

Validation Report¶

After validating an XML document that has a Schematron file bound, Validation Report (in the ⋮ menu under Schematron Tools, or via the report button in the Validation panel's PROBLEMS header) opens a Schematron Report tool tab. It shows the document name, the Schematron file, an error/warning summary, and a table with one row per finding - severity, line, message, the failed rule/test expression, and the failing node's XPath context. Clicking a row jumps to that line in the editor.

The report can be exported with Save Report (HTML) (a self-contained HTML file) or Save SVRL (XML) (the raw SVRL result of the run). See Detailed Schematron Report in the Unified Shell guide.

Creating Schematron Rules¶

Basic Structure¶

<?xml version="1.0" encoding="UTF-8"?>
<schema xmlns="http://purl.oclc.org/dsdl/schematron">
    <title>My Validation Rules</title>

    <pattern name="Invoice Validation">
        <rule context="invoice">
            <assert test="@date">
                Every invoice must have a date attribute.
            </assert>
            <assert test="customer">
                Every invoice must have a customer element.
            </assert>
        </rule>
    </pattern>
</schema>

Common Rule Patterns¶

Required Field¶

<rule context="order">
    <assert test="orderNumber">
        Order number is required.
    </assert>
</rule>

Conditional Requirement¶

<rule context="order">
    <assert test="not(@status='shipped') or shipDate">
        Shipped orders must have a ship date.
    </assert>
</rule>

Value Comparison¶

<rule context="order">
    <assert test="endDate >= startDate">
        End date must be after start date.
    </assert>
</rule>

Sum Validation¶

<rule context="invoice">
    <assert test="sum(item/price) = total">
        Total must equal sum of item prices.
    </assert>
</rule>

Unique Values¶

<rule context="items">
    <assert test="count(item) = count(distinct-values(item/@id))">
        All item IDs must be unique.
    </assert>
</rule>

Cross-Reference¶

<rule context="orderLine">
    <assert test="@productId = //product/@id">
        Product ID must reference an existing product.
    </assert>
</rule>

Testing Rules¶

Test Against XML Files¶

Open the Validation activity and choose ⋮ → Schematron Tools → Tester
Pick the Schematron file with Browse… (the one bound to the active document is pre-loaded) and add the XML file(s) to test with Add XML Files
Click Run Tests and review the results in the Tester tab

For a quick check of many files at once, the Explorer's Schematron bar validates the selected XML files against a sticky Schematron in one click.

Integration with XML Editor¶

Use Schematron validation directly in the XML Editor:

Open an XML file in the editor
In the Validation panel's SOURCES section, click the Schematron row to select your Schematron file (or pick one from its favorites menu) - or simply drop a .sch / .schematron file from your file manager onto that row or onto the Explorer's Schematron picker
Press Validate (F8) or click Run Validation in the panel; with Validate while typing on, the document is re-checked as you edit
Errors are highlighted in the editor; click a problem to jump to its location

In the PROBLEMS panel below the editor, Schematron findings carry a Schematron source badge (so they are easy to tell apart from XSD errors), and hovering a row shows the full message together with the failed test expression and the failing node's XPath. For a complete overview of a run, open the Validation Report.

If a rule defines Schematron Quick Fixes (SQF), the matching problems can be corrected automatically — from a right-click Quick Fix menu on the problem rows, from a lightbulb in the editor gutter, or from the Validation Report's Fix column. See Schematron Quick Fixes for the full guide, including how to author fixes.

Favorites Integration¶

Save frequently used Schematron files for quick access:

Add Favorite (Ctrl+D) - Save current file to favorites
Favorites (Ctrl+Shift+D) - Show/hide the favorites panel

XPath Reference¶

Common XPath expressions for Schematron rules:

Expression	Description
`.`	Current node
`@attribute`	Attribute of current node
`child::element`	Child element
`parent::element`	Parent element
`//element`	Any element in document
`count(element)`	Count elements
`string-length(.)`	Length of text content
`contains(., 'text')`	Text contains substring
`starts-with(., 'text')`	Text starts with
`normalize-space(.)`	Normalized whitespace
`sum(element)`	Sum of numeric values
`distinct-values(element)`	Unique values

Supported Formats¶

Format	Support
ISO Schematron (.sch)	Full support
XSLT-based Schematron	Full support

Schematron validation runs on the SchXslt compiler (executed by Saxon), which fully resolves sch:include, sch:extends, and abstract patterns. Schematrons that declare queryBinding="xslt2" or "xslt3" use XPath 2.0/3.0; files without a queryBinding attribute are compiled as xslt2, so existing rule files keep working unchanged.

Keyboard Shortcuts¶

Shortcut	Action
Ctrl+N	New file (Schematron template available)
Ctrl+S	Save file
Ctrl+Shift+S	Save As
F8	Validate the active document
Ctrl+Shift+X	Toggle the Query Console (XPath/XQuery)
Alt+Enter / Ctrl+.	Open the Quick Fix chooser on the current line
Ctrl+D	Add to favorites
Ctrl+Shift+D	Toggle favorites

Tips¶

Start simple - Begin with basic rules and add complexity
Test both ways - Test with valid and invalid sample files
Clear messages - Write helpful error messages for users
Use patterns - Group related rules into patterns
Query Console - Press Ctrl+Shift+X to test XPath expressions against the open document before using them in a rule

Troubleshooting¶

Problem	Solution
Rule not firing	Check the context XPath matches elements
False positives	Review your test condition logic
Namespace issues	Add namespace declarations to schema
Performance slow	Optimize complex XPath expressions

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