Distinguished Fields vs. Promoted Properties in Biztalk

Both can be used to promote elements and attributes.

1. Distinguished fields
In general use Distinguished fields if you want to just use them in Orchestration

Summary
- No restriction on field length
- No participation in Routing
- No seperate property Schema
- Not accesible by standard pipeline components
- Not support to promote values in a record

2. Promoted Properties

These are generally used with Routing.

Summary
- Used in publish and subscribe in the Msgbox
- Field Restictions ( 255)
- Seperate Property schema
- Restricted in the XSD types support compared to distinguished properties
- can be used on records with Simple Content type

ThumbRule
Use Distinguish properties as they are lightweight unless you need them for any special stuff like Routing,

Tracking, Correlation or custom pipeline behavior.

SOURCE URL:
http://biztalkland.blogspot.com/2005_03_27_biztalkland_archive.html
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Some tips on Biztalk:
(1) In which scenarios would use a "promoted property" vs "distinguished fields"?
The rule here is, if you dont want the schema element to appear in send port filters/debugging information

then make it a distinguished field.

(2) How does one enable subscriptions in BizTalk?
A filter on the Send Port is the first step to enable subscriptions in BizTalk.

(3) Is it necessary for all .NET components being called from an Orchestration be Serializable?
Yes it is necessary. There are cases where a .NET component need not be Serializable.

(4) How does one enable Correlations in BizTalk?
First create a Correlation type and then create an instance of it.

(5) List out the three important things to consider while designing a BizTalk orchestration!
The Incoming data format, The Business process and The Outgoing data format.

SOURCE URL:
http://www.codeproject.com/useritems/BizTalkInterviewQuestions.asp