Property Promotion in BizTalk is usually about taking values from incoming message and moving them into the context of the message, so they are easily accessible and usable for routing. The context of message is a set of metadata about a message that resides in the message box with the message, allowing different part of BizTalk to read in a small set of metadata instead of the entire message, in case a value from a message needed at run time.
Below are three options for Property Promotion:
- Distinguished Field
- Property Schema
Note: Only those fields can be promoted as distinguished field or Property schema which occur only once in the message.
Following error will happen when promoting a value that can occur multiple times
Difference between Distinguished Fields & Property Schema
|Distinguished Fields||Property Schema|
|These field are excellent and fast way to both accessing and writing values to and from in Orchestration||Only Promoted Property can have used for message routing, correlations and can be used in orchestrations|
|These fields are restricted to contains values that comes from some element (that can occur only once)||It can contain data that is purely metadata about the message|
|Do not participate in routing|
IsPromoted = false
|Only promoted property can be used for tracking purposes with the build-in tracking functionality|
|Do not have a size limitation||They are restricted to 256 characters|
|Do not require the creation of a corresponding property schema||Create a separately maintained property schema|
|They are not persisted to the Message Box database. Instead, they are essentially XPath aliases, which simply point to the appropriate XML data field.||Promoted properties are persisted to the Message box database. The Message box generate a large join in SQL Server each time a message is published, which is basically a join between the Context of Message, the possible properties, and the properties of all subscribers. So the no. of Promoted Properties should be keep minimum|
|Use in Orchestration as below: MessageName.RecordName.FieldName||Use in Orchestration as below: MessageName(|
|Distinguished field through the BizTalk API: pInMsg.Context.Write(“theDistinguishedProperty”,|
|Promote properties through the BizTalk API: message.Context.Promote(“MessageType”, “http://schemas.microsoft.com/BizTalk/2003/system-properties”, messageType);|
XPath is much slower than Promoted Property and Distinguished Field. XPath function requires the Orchestration Engine to load the entire message into the memory to evaluate the XPath expression.
XPath should only use for getting and setting value of element that are recurring where Promoted Property and Distinguished field can not helpful.