The value returned for the output parameter will be stored in the tOutParams array.

Are you still getting an error?

Have you tried doing this instead?

SELECT EnsLib_HL7.Message.RawContent INTO :FullMessage, head.ID As ID, {fn RIGHT(%EXTERNAL(head.TimeCreated),999 )} As TimeCreated, head.SessionId As Session, head.Status As Status,
...

Also, I've gotta make a plug for keeping in mind the disclaimers on the use of RawContent:
Note that this is a truncated version suitable for use in SQL results and visual inspection, but not a complete or definitive representation of the document.  

You can create a custom REST web service, use Muhammed's approach to fetch the data, and then output the raw CSV as the response.

One complication here is that %DisplayFormatted only outputs to files. You could consider outputting to the file, then read that file and output it in your response, but in a web service it would be best to output to the response directly.

In that case, you might just iterate through the result set using %Next() and either use %Print(",") to output each row or build your own row by using %Get for each column to output and adding commas between columns.

You can log %msg to get more information about the error:

set ^ztest($now(),"%msg") = $G(%msg)

In the management portal you can view that under System Explorer >> Globals. From terminal you can use zwrite. In both cases, make sure you're in the correct namespace:

zwrite ^ztest

Does my sample code work in your local HS installation?

If this code is being run in FileXmlTransLaboIn, you can get the name of the config item from %Ensemble("ConfigName") and then query based on that.

set configName=%Ensemble("ConfigName")
&sql(SELECT Category INTO :itemCat FROM Ens_Config.Item WHERE Name=:configName)

It's possible that your data set doesn't include the name Xiang. Run "zwrite ^Data" and choose a name to search for.

This piece from your code works for me:

set idx = ""
for {
    set idx = $o(^Data(idx)) quit:idx=""
    write !,"idx: "_idx
    write ^Data(idx, "name")
}

What response did you get?

You can query Ens_Config.Item on ClassName:

SELECT ID, Category FROM Ens_Config.Item WHERE ClassName = "EnsLib.HL7.Service.FileService"

But you'll want to keep in mind that a production can have multiple items that use the same class, so this query could return multiple rows all with different categories.

Category applies to the item as it is configured in the production, not to the underlying class it uses.

This is a great question. In your example you haven't created an index for name. But you can still find entries by name if you iterate through all of the entries.

You can do that like this:

set searchName="Xiang"

set id=""  
for {
    set id=$ORDER(^Data(id))  
    quit:id=""
    if ^Data(id,"name")=searchName {
        write ^Data(id,"surname"),":",^Data(id,"name"),":",^Data(id,"birthday"),!
    }
}

This gave me the output:

Kevin:Xiang:36411

The key command in this code is $ORDER. You'll definitely want to review the $ORDER documentation to understand what it is doing.

Another convenient utility is zwrite, which will allow you to see all of the entries you inserted in ^Data.

This is what it looks like if I run zwrite in the terminal:

DEMO> zwrite ^Data
^Data(1,"birthday")=44136
^Data(1,"name")="Murray"
^Data(1,"surname")="Nataliya"
^Data(2,"birthday")=33465
^Data(2,"name")="Black"
^Data(2,"surname")="Samantha"
^Data(3,"birthday")=49183
^Data(3,"name")="Lee"
^Data(3,"surname")="Liza"
^Data(4,"birthday")=44951
^Data(4,"name")="Ravazzolo"
^Data(4,"surname")="Quigley"
^Data(5,"birthday")=39369
^Data(5,"name")="Faust"
^Data(5,"surname")="Zoe"
^Data(6,"birthday")=31477
^Data(6,"name")="Gomez"
^Data(6,"surname")="Maria"
^Data(7,"birthday")=31574
^Data(7,"name")="Eagleman"
^Data(7,"surname")="Samantha"
^Data(8,"birthday")=62100
^Data(8,"name")="Ragon"
^Data(8,"surname")="Jose"
^Data(9,"birthday")=35228
^Data(9,"name")="Lee"
^Data(9,"surname")="Pam"
^Data(10,"birthday")=47920
^Data(10,"name")="Evans"
^Data(10,"surname")="Will"
^Data(11,"birthday")=63253
^Data(11,"name")="Rogers"
^Data(11,"surname")="Uma"
^Data(12,"birthday")=55410
^Data(12,"name")="Novello"
^Data(12,"surname")="Terry"
^Data(13,"birthday")=64002
^Data(13,"name")="Perez"
^Data(13,"surname")="Terry"
^Data(14,"birthday")=39783
^Data(14,"name")="Uberoth"
^Data(14,"surname")="Wolfgang"
^Data(15,"birthday")=46360
^Data(15,"name")="Zubik"
^Data(15,"surname")="Phyllis"
^Data(16,"birthday")=33271
^Data(16,"name")="Yang"
^Data(16,"surname")="Andrew"
^Data(17,"birthday")=40437
^Data(17,"name")="Zampitello"
^Data(17,"surname")="Martin"
^Data(18,"birthday")=46985
^Data(18,"name")="Orwell"
^Data(18,"surname")="Ralph"
^Data(19,"birthday")=42733
^Data(19,"name")="Waterman"
^Data(19,"surname")="Diane"
^Data(20,"birthday")=45346
^Data(20,"name")="Gold"
^Data(20,"surname")="Imelda"
^Data(21,"birthday")=37976
^Data(21,"name")="Frost"
^Data(21,"surname")="Richard"
^Data(22,"birthday")=41319
^Data(22,"name")="Koenig"
^Data(22,"surname")="Robert"
^Data(23,"birthday")=40915
^Data(23,"name")="Minichillo"
^Data(23,"surname")="Molly"
^Data(24,"birthday")=30632
^Data(24,"name")="Yang"
^Data(24,"surname")="Neil"
^Data(25,"birthday")=59938
^Data(25,"name")="Wilson"
^Data(25,"surname")="Wolfgang"
^Data(26,"birthday")=59897
^Data(26,"name")="Zampitello"
^Data(26,"surname")="Jules"
^Data(27,"birthday")=37417
^Data(27,"name")="Avery"
^Data(27,"surname")="Patricia"
^Data(28,"birthday")=46217
^Data(28,"name")="Edwards"
^Data(28,"surname")="Angelo"
^Data(29,"birthday")=64401
^Data(29,"name")="Humby"
^Data(29,"surname")="Clint"
^Data(30,"birthday")=44599
^Data(30,"name")="Nichols"
^Data(30,"surname")="Joe"
^Data(31,"birthday")=36633
^Data(31,"name")="Anderson"
^Data(31,"surname")="Zeke"
^Data(32,"birthday")=54905
^Data(32,"name")="Isaksen"
^Data(32,"surname")="John"
^Data(33,"birthday")=39307
^Data(33,"name")="Hanson"
^Data(33,"surname")="Heloisa"
^Data(34,"birthday")=55578
^Data(34,"name")="Jenkins"
^Data(34,"surname")="Filomena"
^Data(35,"birthday")=39818
^Data(35,"name")="Orlin"
^Data(35,"surname")="Nellie"
^Data(36,"birthday")=61299
^Data(36,"name")="Allen"
^Data(36,"surname")="Rob"
^Data(37,"birthday")=46647
^Data(37,"name")="Koivu"
^Data(37,"surname")="Mario"
^Data(38,"birthday")=61880
^Data(38,"name")="Winters"
^Data(38,"surname")="Al"
^Data(39,"birthday")=59597
^Data(39,"name")="Yoders"
^Data(39,"surname")="Nellie"
^Data(40,"birthday")=32317
^Data(40,"name")="Yoders"
^Data(40,"surname")="Stavros"
^Data(41,"birthday")=65110
^Data(41,"name")="Gallant"
^Data(41,"surname")="Umberto"
^Data(42,"birthday")=64331
^Data(42,"name")="Huff"
^Data(42,"surname")="Edward"
^Data(43,"birthday")=49679
^Data(43,"name")="Xavier"
^Data(43,"surname")="Barbara"
^Data(44,"birthday")=62300
^Data(44,"name")="Xander"
^Data(44,"surname")="Natasha"
^Data(45,"birthday")=38052
^Data(45,"name")="Quine"
^Data(45,"surname")="Brian"
^Data(46,"birthday")=45772
^Data(46,"name")="Mara"
^Data(46,"surname")="Nataliya"
^Data(47,"birthday")=61894
^Data(47,"name")="Lopez"
^Data(47,"surname")="Sally"
^Data(48,"birthday")=47017
^Data(48,"name")="Solomon"
^Data(48,"surname")="Jocelyn"
^Data(49,"birthday")=65868
^Data(49,"name")="Quigley"
^Data(49,"surname")="Ted"
^Data(50,"birthday")=46776
^Data(50,"name")="Gallant"
^Data(50,"surname")="Angelo"
^Data(51,"birthday")=45919
^Data(51,"name")="Rotterman"
^Data(51,"surname")="Juanita"
^Data(52,"birthday")=49368
^Data(52,"name")="Kratzmann"
^Data(52,"surname")="Neil"
^Data(53,"birthday")=36273
^Data(53,"name")="Lennon"
^Data(53,"surname")="Kirsten"
^Data(54,"birthday")=57894
^Data(54,"name")="Dunlap"
^Data(54,"surname")="Gertrude"
^Data(55,"birthday")=52763
^Data(55,"name")="Yakulis"
^Data(55,"surname")="Maria"
^Data(56,"birthday")=45293
^Data(56,"name")="Quigley"
^Data(56,"surname")="Wilma"
^Data(57,"birthday")=30457
^Data(57,"name")="Paladino"
^Data(57,"surname")="Jeff"
^Data(58,"birthday")=44654
^Data(58,"name")="Jafari"
^Data(58,"surname")="Patrick"
^Data(59,"birthday")=47310
^Data(59,"name")="Chadwick"
^Data(59,"surname")="Wolfgang"
^Data(60,"birthday")=32840
^Data(60,"name")="Orwell"
^Data(60,"surname")="Andrew"
^Data(61,"birthday")=46156
^Data(61,"name")="Quilty"
^Data(61,"surname")="Josephine"
^Data(62,"birthday")=63361
^Data(62,"name")="Zimmerman"
^Data(62,"surname")="Ted"
^Data(63,"birthday")=46049
^Data(63,"name")="Adams"
^Data(63,"surname")="Valery"
^Data(64,"birthday")=40616
^Data(64,"name")="Jafari"
^Data(64,"surname")="Jules"
^Data(65,"birthday")=31115
^Data(65,"name")="McCoy"
^Data(65,"surname")="Laura"
^Data(66,"birthday")=34784
^Data(66,"name")="Quilty"
^Data(66,"surname")="Elvis"
^Data(67,"birthday")=54016
^Data(67,"name")="Ingleman"
^Data(67,"surname")="Greta"
^Data(68,"birthday")=36432
^Data(68,"name")="Walker"
^Data(68,"surname")="Dick"
^Data(69,"birthday")=60717
^Data(69,"name")="Zampitello"
^Data(69,"surname")="Jose"
^Data(70,"birthday")=50594
^Data(70,"name")="DeSantis"
^Data(70,"surname")="Brendan"
^Data(71,"birthday")=33822
^Data(71,"name")="Anderson"
^Data(71,"surname")="Bart"
^Data(72,"birthday")=41826
^Data(72,"name")="Fripp"
^Data(72,"surname")="Molly"
^Data(73,"birthday")=30840
^Data(73,"name")="Ironhorse"
^Data(73,"surname")="Diane"
^Data(74,"birthday")=59455
^Data(74,"name")="Jaynes"
^Data(74,"surname")="Al"
^Data(75,"birthday")=42430
^Data(75,"name")="Chesire"
^Data(75,"surname")="Emily"
^Data(76,"birthday")=34392
^Data(76,"name")="Jenkins"
^Data(76,"surname")="Pam"
^Data(77,"birthday")=45341
^Data(77,"name")="Hanson"
^Data(77,"surname")="Sally"
^Data(78,"birthday")=54498
^Data(78,"name")="Nichols"
^Data(78,"surname")="Uma"
^Data(79,"birthday")=38272
^Data(79,"name")="Goncharuk"
^Data(79,"surname")="Zelda"
^Data(80,"birthday")=55832
^Data(80,"name")="Avery"
^Data(80,"surname")="Greta"
^Data(81,"birthday")=45135
^Data(81,"name")="Nagel"
^Data(81,"surname")="Michael"
^Data(82,"birthday")=42670
^Data(82,"name")="Quince"
^Data(82,"surname")="Terry"
^Data(83,"birthday")=35127
^Data(83,"name")="Jackson"
^Data(83,"surname")="Susan"
^Data(84,"birthday")=44011
^Data(84,"name")="Marks"
^Data(84,"surname")="Milhouse"
^Data(85,"birthday")=47140
^Data(85,"name")="Sato"
^Data(85,"surname")="Greta"
^Data(86,"birthday")=57187
^Data(86,"name")="Ingersol"
^Data(86,"surname")="Ted"
^Data(87,"birthday")=35111
^Data(87,"name")="West"
^Data(87,"surname")="Wilma"
^Data(88,"birthday")=60618
^Data(88,"name")="Braam"
^Data(88,"surname")="Greta"
^Data(89,"birthday")=45237
^Data(89,"name")="Klausner"
^Data(89,"surname")="Kyra"
^Data(90,"birthday")=51816
^Data(90,"name")="Eastman"
^Data(90,"surname")="Andrew"
^Data(91,"birthday")=63181
^Data(91,"name")="Nathanson"
^Data(91,"surname")="Robert"
^Data(92,"birthday")=56444
^Data(92,"name")="Newton"
^Data(92,"surname")="Mo"
^Data(93,"birthday")=33670
^Data(93,"name")="Xavier"
^Data(93,"surname")="Brenda"
^Data(94,"birthday")=60262
^Data(94,"name")="Ironhorse"
^Data(94,"surname")="Josephine"
^Data(95,"birthday")=51967
^Data(95,"name")="Klingman"
^Data(95,"surname")="Ralph"
^Data(96,"birthday")=40383
^Data(96,"name")="Donaldson"
^Data(96,"surname")="Stuart"
^Data(97,"birthday")=50563
^Data(97,"name")="Wells"
^Data(97,"surname")="Clint"
^Data(98,"birthday")=52105
^Data(98,"name")="Leiberman"
^Data(98,"surname")="Rhonda"
^Data(99,"birthday")=36713
^Data(99,"name")="Lepon"
^Data(99,"surname")="Laura"
^Data(100,"birthday")=36411
^Data(100,"name")="Xiang"
^Data(100,"surname")="Kevin"

Next, if you want to add an index on name, you can add entries for each name with a reference to every id that has that name. In the global, it could look like this:

set ^DataIndex("name","Xiang",100)=""
set ^DataIndex("name","Xiang",123)=""

You could then use $ORDER again to iterate through all entries with the name of Xiang:

set id=""
for {
   set id=$ORDER(^DataIndex("name","Xiang",id))
   quit:id=""
   write "ID:",id," has the name Xiang",!
}

Of course, this is all very manual. Modern applications usually define classes that represent a SQL table. The table/class will specify an index on a column, and Caché will create and maintain that index automatically.