It was initially very hard for me to understand the message mapping when we are trained on SAP XI.I browsed help.sap.com and ended up getting more confused. After working with SAP XI for some time however the intuition is changed. I will try to simplify the message mapping by elucidating the concepts in the nutshell. Blog does not cover the message mapping in detail but just gives the basic understanding for any new XI developers. Part 1 of the blog provides a base for conceptual understanding of message mapping with suitable examples.
As we know XI produces the XML documents at the inbound/outbound of the integration pipeline, there is a need for us to map the source XML doc to the target XML doc. Message Mapping editor is a built in feature, which helps to map the source and target XML messages graphically.
In this blog we discuss various terms related to it.
Definition: Message Mapping
Firstly, let me define the message mapping in the way I look at it:
“Message Mapping is nothing but a set of rules for producing target XML from the source XML.These rules are nothing but relations between the source XML tags and target XML tags”.
These rules keep varying according to the business requirements on the source and target XML documents.
Sample Rule :
Illustration of Mapping Error:
Definition: Representation:
Before we proceed further it is better if we have a clear understanding of the 3 terms:
1.
Element
: Simple XML tag.
2.
Attribute
: Property of XML tag.
3.
Node
: Logical grouping of set of XML tags.
In XI it is represented as shown below:
XML representation in XI:
Additionally there is color indicator for the target XML messages:
1.
Red Color
indicates that target nodes/elements/attributes are mandatory and has to be definetly mapped.
2.
Green Color with a red circle
at the bottom indicates that there is a minimum occurrence specified for the tag which has to be met in the mapping.
3.
Green color
indicates that we can map the nodes/elements/attributes according to the requirements.
Color Indication in the Mapping Editor:
Contexts in Message Mapping:
Once the above concepts are clear we can proceed to the most confusing part of message mapping called “Context Handling”.
Initially when I was browsing through the training materials and mapping patterns it was really hard for me to exactly figure out what the term “Context” means. (Forget about context handling and context changing).
Definition: Context
After working out few examples I figured out that: “Context of an element is nothing but just the level (with reference to its parent node) where the XML tag appears in the given XML document”.
Level of any element is set to the immediate parent node by default.
Definition: Context Changing
Once the definition of context is very clear the rest of the terms are automatically clarified.“Context Changing is just changing the level of XML tag (element level in the XSD) in the XML document or It is just the flexibility provided by XI for changing the XSD of the XML document at the runtime”. Example given below might make you to understand it better. I added a
Qualifications
node and
Description
element in the source data type and one
Qual_Desc
element in the target data type.
The context of the
Description
tag is automatically set to the
Qualification
by default in XI which means that always
Description
XML tag occurs under
Qualification
XML tag as shown below.
Source XML message interpretation by the Mapping runtime before context change:
I changed the context of the
Description
tag to the root
MT_SRC
XML tag as shown below.
Source XML message interpretation by the Mapping runtime after context change:
Definition: Context Handling
Contexts in XI can be handled by various ways like
node functions, advanced functions
, which will be, illustrated more in detail in the next blog. We also have queuing mechanisms for handling complex Context Changing in advanced user functions.
Once the above concepts are clear , working with the message mapping and trouble shooting any errors that occurred became relatively very easy for me. Part II will provide some more good examples for playing around with message mapping feature
provided by XI.
You have very neatly elucidated XI mapping basics in this blog. The terminology used in mapping world is difficult to understand for a beginner. I am sure this article which uses simple-plain-vanila English will be a great help.
Great job.
Cheers
Pawan
Regards,
Venkat Neela
Expecting more blogs from you.
Regards,
Ameer.
Very well explained…!!!!
Expecting more such features from you.
All the best..!!!
Vishal Kohli
vishal_kohli@keane.com
Keane
Easy, practical and with a very sense of humor!
It was highly helpful for begineers like us.
Hope to see some more from you..
Thanks,
Younus
this is very important topic for starting sap xi employers…
Thanks
sreenivasulu kaipu
09247500079
srinu.ababxi@gmail.com
Thank you and best regards
Kartik Iyengar~
Great work! It does help beginners like me to understand the concept better.
Thanks,
Birla.
It’s a really great job!!
Thanks for your help!!!
Best
Mirita Mistry
I am new to PI technology. I want to learn Nodefunctions in mapping. So help me on this.
Regards,
Naik,Pune,Infosys.
I would be expecting the same stuff further in next stage of blog.
Hi Sravya,
Good Blog..
Can you clarify me regarding the following
Source XML message interpretation by the Mapping runtime before context change:
Source XML message interpretation by the Mapping runtime after context change:
when you are changing the context for Descriptions you can directly change it to MT_SRC why do you change context for the first to Qualificaitons and then changed to context to MT_SRC
Kindly Explain it briefly
Hi Sravya,
This is a great material for me who is just starting to learn PI…
I’ll be following your blog to be more familiar with it. 🙂
Hi Sravya,
This very useful to for me.
Thanks,
Raman
Thanks.