Example 3 – OPC Unified Architecture

B.3.6 Example 3

The third example provides a more complex Query in which the results are filtered on multiple criteria.

Example 3: Get PersonType.LastName, AnimalType.Name, ScheduleType.Period where a person has a pet and the animal has a feeding schedule and the person has a Zipcode = ‘02138’ and (the Schedule.Period is Daily or Hourly) and Amount to feed is > 10.

Table B.16 describes the NodeTypeDescription parameters used in the example.

Table B.16 – Example 3 - NodeTypeDescription

Type Definition Node	Include Subtypes	QueryDataDescription
		RelativePath	Attribute	Index Range
PersonType	FALSE	“12:LastName”	Value	N/A
		“<12:HasPet>12:AnimalType. 12:Name”	Value	N/A
		“<12:HasPet>12:AnimalType<12:HasSchedule> 12:FeedingSchedule.Period”	Value	N/A

The corresponding ContentFilter is illustrated in Figure B.7.

Figure B.7 – Example 3 filter logic tree

Table B.17 describes the elements, operators and operands used in the example.

Table B.17 – Example 3 ContentFilter

Element[]	Operator	Operand[0]	Operand[1]	Operand[2]	Operand[3]
0	And	Element Operand= 1	ElementOperand = 2
1	And	ElementOperand = 4	ElementOperand = 6
2	And	ElementOperand = 3	ElementOperand = 9
3	Or	ElementOperand = 7	ElementOperand = 8
4	RelatedTo	AttributeOperand = NodeId: 12:PersonType, BrowsePath “.”, Attribute: NodeId	ElementOperand = 5	AttributeOperand = NodeId: 12:HasPet, BrowsePath “.”, Attribute: NodeId	LiteralOperand = ‘1’
5	RelatedTo	AttributeOperand = Node: 12:AnilmalType, BrowsePath “.”, Attribute: NodeId Alias: AT	AttributeOperand = NodeId: 12:FeedingScheduleType, BrowsePath “.”, Attribute: NodeId Alias: FST	AttributeOperand = NodeId: 12:HasSchedule, BrowsePath “.”, Attribute: NodeId	LiteralOperand = ‘1’
6	Equals	AttributeOperand = NodeId: 12:PersonType BrowsePath 12:Zipcode “.”, Attribute: Value	LiteralOperand = ‘02138’
7	Equals	AttributeOperand = NodeId: 12:PersonType BrowsePath “12:HasPet>12:AnimalType<12:HasSchedule>12: FeedingSchedule/12:Period”, Attribute: Value Alias: FST	LiteralOperand = ‘Daily’
8	Equals	AttributeOperand = NodeId: 12:PersonType BrowsePath “12:HasPet>12:AnimalType<12:HasSchedule>12: FeedingSchedule/12:Period”, Attribute: Value Alias: FST	LiteralOperand = ‘Hourly’
9	Greater Than	AttributeOperand = NodeId: 12:PersonType BrowsePath “12:HasPet>12:AnimalType<12:HasSchedule>12: FeedingSchedule/12:Amount”, Attribute: Value Alias: FST	ElementOperand = 10
10	Cast	LiteralOperand = 10	AttributeOperand = NodeId: Int32, BrowsePath “.”, Attribute: NodeId

The results from this query would contain the QueryDataSets shown in Table B.18.

Table B.18 – Example 3 QueryDataSets

NodeId	TypeDefinition NodeId	RelativePath	Value
12:30 (JFamily1)	PersonType	“.12:LastName”	Jones
		“<12:HasPet>12:PersonType. 12:Name”	Rosemary
			Basil
		“<12:HasPet>12:AnimalType<12:HasSchedule>12:FeedingSchedule. 12:Period”	Hourly
			Daily