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| Cogito-Ergo-Sum |
 Posted: Fri Feb 04, 2011 3:09 am Post subject: Mapping node : Target messages sourced from a database |
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Master
Joined: 07 Feb 2006
Posts: 293
Location: Bengaluru, India
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How do you get the Mapping node to get multiple target messages depending on the rows returned by a database select ? 
I have read the documentation , confirmed that the database table does have multiple rows for the SELECT criterion and yet I keep getting a single message as the output. In Map Script, I have $db:select set to match the value of the input message. There is a 'for' row immediately below $db:select whose value I have set to $db:select. I am unable to make the $target a child of this 'for'. I think, this is required to get multiple messages as described in this link.
Excerpt:
| Quote: |
| The behavior of the map is determined by the position of the 'for' row in the Spreadsheet pane. For example, if the results of the $db:select statement matched five rows in the database, and the 'for' row is the parent of the $target entry in the Spreadsheet pane, five complete messages are generated by the mapping node. If the 'for' row is positioned within the message body, one message is generated with five repeating elements in the message body. |
Thus, I went ahead with population of the elements under $target. The build et al goes fine but when I run the flow, I get only a single message in output.
What am I missing ? 
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Debugging tip:When you have eliminated all which is impossible, then whatever remains, however improbable, must be the truth.
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| fatherjack |
| Posted: Fri Feb 04, 2011 3:22 am Post subject: Re: Mapping node : Target messages sourced from a database |
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Knight
Joined: 14 Apr 2010
Posts: 522
Location: Craggy Island
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| Cogito-Ergo-Sum wrote: |
| What am I missing ? |
Can't say as I haven't seen your mapping node and map script. However, from experience it can be quite tricky to get your 'for' loops in the right place in the mapping node. I much prefer to use a compute node and propagate the messages from the ESQL code.
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| Cogito-Ergo-Sum |
| Posted: Fri Feb 04, 2011 3:31 am Post subject: |
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Master
Joined: 07 Feb 2006
Posts: 293
Location: Bengaluru, India
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| Quote: |
| I much prefer to use a compute node and propagate the messages from the ESQL code. |
I might do the same, eventually. But, it would have been nice to get the Mapping node without having to pull out hair... 
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Debugging tip:When you have eliminated all which is impossible, then whatever remains, however improbable, must be the truth.
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| fatherjack |
| Posted: Fri Feb 04, 2011 3:58 am Post subject: |
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Knight
Joined: 14 Apr 2010
Posts: 522
Location: Craggy Island
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| Cogito-Ergo-Sum wrote: |
| Quote: |
| I much prefer to use a compute node and propagate the messages from the ESQL code. |
I might do the same, eventually. But, it would have been nice to get the Mapping node without having to pull out hair... |
In the spreadsheet pane of the mapping msgmap what is the sequence of the mapping statements?
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| fatherjack |
| Posted: Fri Feb 04, 2011 5:44 am Post subject: Re: Mapping node : Target messages sourced from a database |
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Knight
Joined: 14 Apr 2010
Posts: 522
Location: Craggy Island
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| Cogito-Ergo-Sum wrote: |
| I am unable to make the $target a child of this 'for'. |
Right click $target and then select 'for'. Then enter $db:select in the Value field. It's much harder (impossible?) to do using drag and drop.
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| Cogito-Ergo-Sum |
| Posted: Fri Feb 04, 2011 5:57 am Post subject: |
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Master
Joined: 07 Feb 2006
Posts: 293
Location: Bengaluru, India
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| Quote: |
| In the spreadsheet pane of the mapping msgmap what is the sequence of the mapping statements? |
There are two sources - $source and $db:select
First, $db:select, whose value is set to a $source element.
$db:select has a child 'for' whose value is set to $db:select.
$target (at the same level as $db:select)
$target has a child Properties set to $source/Properties
$target has another child which is a message type. The children of this message type has been mapped from $source.
_________________
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Debugging tip:When you have eliminated all which is impossible, then whatever remains, however improbable, must be the truth.
---Sherlock Holmes |
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| fatherjack |
| Posted: Fri Feb 04, 2011 6:01 am Post subject: |
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Knight
Joined: 14 Apr 2010
Posts: 522
Location: Craggy Island
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| Cogito-Ergo-Sum wrote: |
| $target (at the same level as db:select) |
That could be the problem. Try dragging the $target onto the 'for'.
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| Cogito-Ergo-Sum |
| Posted: Fri Feb 04, 2011 6:06 am Post subject: Re: Mapping node : Target messages sourced from a database |
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Master
Joined: 07 Feb 2006
Posts: 293
Location: Bengaluru, India
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| Quote: |
| Right click $target and then select 'for'. Then enter $db:select in the Value field. It's much harder (impossible?) to do using drag and drop. |
It was one of my earliest attempt. That makes $db:select out of scope.
I also tried the following.
Select an element under $target.
Select an element under $db:select.
Right-click and select 'Map from source'.
Mapping is done by Toolkit automagically such that $db:select - with for as it's child - somewhere under $target.
But, multiple messages do not appear.
_________________
ALL opinions are welcome.
-----------------------------
Debugging tip:When you have eliminated all which is impossible, then whatever remains, however improbable, must be the truth.
---Sherlock Holmes |
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| Cogito-Ergo-Sum |
| Posted: Fri Feb 04, 2011 6:13 am Post subject: SOLVED |
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Master
Joined: 07 Feb 2006
Posts: 293
Location: Bengaluru, India
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ok, I got it !! 
Removed $db:select. Selected $target, right-clicky-clicky, then clicky-clicky 'Select Data Source...'. This creates new $db:select a 'for' child and then $target as its child. And so, everything working now !
_________________
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Debugging tip:When you have eliminated all which is impossible, then whatever remains, however improbable, must be the truth.
---Sherlock Holmes |
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| mqjeff |
| Posted: Fri Feb 04, 2011 6:16 am Post subject: |
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Grand Master
Joined: 25 Jun 2008
Posts: 17447
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If I understand the issue, you want to do two things:
- Iterate over the rows that are returned from the database
- Transform the row into different types of output messages based on the contents of the row
Is that correct?
To accomplish #1, you need to use the For macro, as El Padre Borracho suggests.
To accomplish #2, you likely need to use an if and submaps. |
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| Cogito-Ergo-Sum |
| Posted: Fri Feb 04, 2011 6:23 am Post subject: |
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Master
Joined: 07 Feb 2006
Posts: 293
Location: Bengaluru, India
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The first item is required; and, I solved it only recently.
El Padre Borracho ? muchos apologies, my espanol not good. But, is that Father Drunkard ??
_________________
ALL opinions are welcome.
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Debugging tip:When you have eliminated all which is impossible, then whatever remains, however improbable, must be the truth.
---Sherlock Holmes |
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| mqjeff |
| Posted: Fri Feb 04, 2011 6:43 am Post subject: |
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Grand Master
Joined: 25 Jun 2008
Posts: 17447
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| Cogito-Ergo-Sum wrote: |
| The first item is required; and, I solved it only recently. |
Yes, you posted that you solved it whilst I was writing my post.
| Cogito-Ergo-Sum wrote: |
| El Padre Borracho ? muchos apologies, my espanol not good. But, is that Father Drunkard ?? |
Ich spreche keine espanol myself. But, yes, Father Drunkard. "Father jack" is a character from a British TV show, who is famous for drinking all the time, and fatherjack who posts here tries to live up to the name, at least whilst posting here.
Having not met the chap, I can't say if it's true in real life. But if we're ever in the same bar in the same country, the first round's on me and damned be he that first cries Hold, Enough! |
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| Cogito-Ergo-Sum |
| Posted: Fri Feb 04, 2011 7:54 am Post subject: |
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Master
Joined: 07 Feb 2006
Posts: 293
Location: Bengaluru, India
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| Quote: |
| Ich spreche keine espanol myself |
Das ist Duestch ?
Yes, wikipedia told me about Father Jack.
_________________
ALL opinions are welcome.
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Debugging tip:When you have eliminated all which is impossible, then whatever remains, however improbable, must be the truth.
---Sherlock Holmes |
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| mqjeff |
| Posted: Fri Feb 04, 2011 7:57 am Post subject: |
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Grand Master
Joined: 25 Jun 2008
Posts: 17447
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| Cogito-Ergo-Sum wrote: |
| Quote: |
| Ich spreche keine espanol myself |
Das ist Duestch ? |
Only as much as my Spanish was Spanish. (also, Deutche, I believe) |
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| fjb_saper |
| Posted: Fri Feb 04, 2011 8:55 pm Post subject: |
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Grand High Poobah
Joined: 18 Nov 2003
Posts: 20756
Location: LI,NY
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| mqjeff wrote: |
| Cogito-Ergo-Sum wrote: |
| Quote: |
| Ich spreche keine espanol myself |
Das ist Duestch ? |
Only as much as my Spanish was Spanish. (also, Deutche, I believe) |
Deutsch for the non foreign language challenged. 
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