First data that represents a level associated with an element within an expression, such as an XPath expression, is generated from the expression, and stored in one or more columns of a table. Second data that represents a condition on an attribute of the element is generated from the expression, and stored in one or more columns of the same or a different table. A plurality of expressions can be processed as such, and a determination made whether any of the expressions match with a given hierarchical data item, such as an XML document, that includes a value that corresponds to an attribute that is associated with an element that resides at a particular level within the data item. Such determination is made based on whether the particular level matches the first data and the value satisfies the second data associated with a given expression.