We came to know it is issue with Adapter Alias in Get Function , it should be "MONGO" instead of "MongoDB" , after changing the Adapter Alias we were able to retrieve the data correctly.
But once we retrieved the data and assigning it to JSON (Schema generated with Sample data) Output Card it is failing
(Offset 0: Map Number 0 (SFC_PeopleSoft_Voucher_Inv), DI 000000000000:)
Building TYPE X'0006' (JSON JSON).
(Level 1: Offset 0, len 0, comp 1 of 0, #1, DI 000000000001:)
Start of Parse of output TYPE X'0006' (JSON JSON).
(Level 1: Offset 0, len 0, comp 1 of 0, #1, DI 000000000001:)
External Parser returned Error:
TYPE X'10000' (Invalid Element as root).
(Level 1: Offset 0, len 0, comp 1 of 0, #1, DI 000000000001:)
Data at offset 0 ('[<LF>{ "PartnerI') was found to be of TYPE
X'0006' (JSON JSON).
(Level 1: Offset 0, len 0, comp 1 of 0, #1, DI 000000000002:)
End of Parse of output TYPE X'0006' (JSON JSON).

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Narendra Chimakurthi
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Original Message:
Sent: Fri May 28, 2021 06:12 AM
From: Paul Brett
Subject: ITX Get Function Not returning Data from Mongo Collection
It is likely your PARSE() is failing. Try the rule without this (change the Typetree object to a text blob) and see if you get a result then.
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Paul Brett
IBM Sterling Transformation Extender (ITX) Client Support
Original Message:
Sent: Wed May 26, 2021 07:29 PM
From: Narendra Chimakurthi
Subject: ITX Get Function Not returning Data from Mongo Collection
Hi ,
I am trying to Query MongoDB in a Rule
=PARSE(GET("MongoDB"," -HOST mongodb://<user>:<password>@MongoHost1.corp.com,MongoHost2.corp.com/?replicaSet=DEV01&readPreference=primary&connectTimeoutMS=10000&authSource=$external&authMechanism=PLAIN -DATABASE APDB -COLLECTION Header -QUERY '{""HeaderId"": ""TEST-6100826920""}' -TV"))
but the rule is not retuning and result, i see data is available and able to query the same using MongoDB Client software.
the Map runs Successfully , it does not fail and No Error in Trace and Audit log files.
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Narendra Chimakurthi
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#IBMSterlingTransformationExtender
#DataExchange