QueryFilterNode Object
A QueryFilterNode object represents one node in the query-expression tree.
A query expression consists of one or more QueryFilterNode
objects arranged hierarchically. The root node is created by the QueryDef
object's BuildFilterOperator
method.
The remaining nodes are all instances of the QueryFilterNode class.
Each node consists of one or more filters and a Boolean operator (specified
using the BoolOp constants
).
To add a filter to a node, you call the node's BuildFilter
method.
Using this method, you specify a field and a specific value to compare,
and you specify the comparison operator to use (one of the CompOp constants
).
Although the node uses a Boolean operator, you can add any number
of filters to a node with the BuildFilter method.
You can also add other nodes. Using the BuildFilterOperator
method
of QueryFilterNode, you can add nodes just as if they were an additional
filter. By nesting nodes in this fashion, you can create complex query
expressions with the nodes and filters forming a tree.