XPath Operators
For XPath Query Constraints
The following operators can be used in XPath query constraints, both in Mendix Studio Pro and in Java code:
| Operator | Description | Example | Return value |
|---|---|---|---|
= | Equal to | price = 9.80 | true if price is 9.80, false if price is 9.90 |
!= | Not equal to | price != 9.80 | true if price is 9.90, false if price is 9.80 |
< | Less than | price < 9.80 | true if price is 9.70, false if price is 9.80 |
<= | Less than or equal to | price <= 9.80 | true if price is 9.80, false if price is 9.90 |
> | Greater than | price > 9.80 | true if price is 9.90, false if price is 9.80 |
>= | Greater than or equal to | price >= 9.80 | true if price is 9.80, false if price is 9.70 |
or | Or | price = 9.80 or price = 9.70 | true if price is 9.80, false if price is 9.60 |
and | And | price = 9.80 and amount = 1 | true if price is 9.80 and amount is 1, false if price is 9.70 and amount is 1, false if price is 9.80 and amount is 2, false if price is 9.70 and amount is 2 |
Mathematical operators
In Studio Pro, mathematical operators can be used in XPath constraints that are defined in the model such as the Retrieve object(s) microflow activity or access rule constraints.
Mathematical operators are not allowed in queries that come from the client. For example, they cannot be used in widgets.
The following mathematical operators are supported:
| Operator | Description | Example | Return value |
|---|---|---|---|
+ | Addition | 6 + 4 | 10 |
- | Subtraction | 6 - 4 | 2 |
* | Multiplication | 6 * 4 | 24 |
div | Division | 8 div 4 | 2 |
In Java code, mathematical operators are disabled by default for the XPathQuery API, but can be enabled using the allowMathOperators method. For example:
Core.createXPathQuery("//Module.Entity[attr1 + attr2 = 42]")
.allowMathOperators(true)
.execute(context);Operator Behavior
The behavior of operators may differ based on the database type used for your Mendix application. The Mendix runtime generates a SQL query for the XPath you have configured. This query can be interpreted differently by different database types. For example, HSQLDB will ignore trailing spaces when using the = operator, whereas PostgreSQL will take those into consideration.