topic Re: Assigning values to context variables in Talend Studio

Assigning values to context variables

_AnonymousUser — Sat, 16 Nov 2024 13:03:30 GMT

Hi all,
Just wondering if you can help me.
I have a DB with 2 columns in it, "filename" & "sql_statement".
I am reading one row from this DB and I want to assign the output to context variables I have created "con_filename" & "con_contents".
I want to then create a file using the value I have stored in "con_filename" and the file being created should be populated with "con_contents".
At the moment I'm selecting the data from the DB fine using a tPostgresqlInput
I am trying to assign the output to context variables here too using a tJavaRow. tJavaRow contains the following.
//Code generated according to input schema and output schema
output_row.filename = input_row.filename;
output_row.sql_statement = input_row.sql_statement;
context.filename = input_row.filename;
context.sql_statement = input_row.sql_statement;
I am then outputting directly to a tFileOutput but I'm getting both values into the file and a null file name. It appears that the context variables never get set.
How do you assign values to context variables.
Thanks in advance,

Dave

Re: Assigning values to context variables

Anonymous — Fri, 04 Mar 2011 12:48:53 GMT

Hi Dave
how many records are fetched from your DB select query?
If its more than 1, check if the last record gives a null or blank values.
The reason is that you are assigning the values to context in a flow. So for each record processed, the values of context changes.
Hope it helps you.
It will be better if you put a screen shot.

Re: Assigning values to context variables

Anonymous — Sat, 05 Mar 2011 20:19:22 GMT

hi,
If you are using context variable to store some value from flow is not a 'best practices' even if it can work
as lijolawrance said in fact the only value that you have is the lasted one into your context
For that use globalMap and a flowToIterate to catch value from the flow (have a look into codeViewer to be sure about the name (key map) of globalMap var).
It's always 'rowName.fieldName' (ex : row1.firstName)
hope it help

Re: Assigning values to context variables

_AnonymousUser — Mon, 07 Mar 2011 09:47:55 GMT

Cheers for getting back to me on it guys.
I'll try using the global variables and will let you know how I get on.

Face

Re: Assigning values to context variables

Anonymous — Mon, 07 Mar 2011 09:54:38 GMT

In reply to your question though LijoLawrance, I am reading in just the one row does this help my cause in making it easier. The value that is being read in is a dynamically changing filename that is created in postgresql.
regards,

Face

Re: Assigning values to context variables

Anonymous — Mon, 07 Mar 2011 10:34:24 GMT

Hi Face,
You can change to what kzone has told.
In what i have told earlier will fail, if there is any null value (Sorry, i missed it).
But i still feel that u need to have a null check.