Talend community forum / Assigning values to context variables

FACE · 2011-03-04 12:55:08

Tags: [context, CSV file, database, delimited file, development, mssql, PostgreSQL]

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

lijolawrance · 2011-03-04 13:48:53

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.

kzone · 2011-03-05 21:19:22

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

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FACE · 2011-03-07 10:47:55

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

dgarrigan · 2011-03-07 10:54:38

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

lijolawrance · 2011-03-07 11:34:24

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.

Last edited by lijolawrance (2011-03-07 11:53:03)

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Unanswered posts

#1 2011-03-04 12:55:08

Assigning values to context variables

#2 2011-03-04 13:48:53

Re: Assigning values to context variables

#3 2011-03-05 21:19:22

Re: Assigning values to context variables

#4 2011-03-07 10:47:55

Re: Assigning values to context variables

#5 2011-03-07 10:54:38

Re: Assigning values to context variables

#6 2011-03-07 11:34:24

Re: Assigning values to context variables

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