topic Re: Purpose of tFlowToIterate and tIterateToFlow in Talend Studio

Purpose of tFlowToIterate and tIterateToFlow

Anonymous — Tue, 26 Jun 2012 16:08:31 GMT

Hi Team,
I was trying to understand the exact purpose of tFlowToIterate and tIterateToFlow components. I tried to understand the components by reading the documentation available for the components, but it could not help me. I didn't exactly understand the actual use.
Can any one explain me with a good scenario that can be easily understandable and grasped.
Thanks in advance for the solutions you are going to post.
Thanks and Regards,
Pavan

Re: Purpose of tFlowToIterate and tIterateToFlow

Anonymous — Wed, 27 Jun 2012 04:31:58 GMT

Hi Pavan
Two scenarios would explain these two components.
Scenario 1---tFlowToIterate:
Let's say we have a mysql table called tableA which contains queries like "select * from tableB". I need to extract thses queries from tableA and use them for extracting data from tableB.
tMysqlInput(tableA)--main(row1)-->tFlowToIterate--Iterate-->tMysqlInput_2--main-->tLogRow
In tMysqlInput_2, I type this expression 'row1.query' in the query text field on tMysqlInput_2 for further extraction.
Scenario 2---tIterateToFlow:
tFileList--Iterate-->tIterateToFlow-->tLogRow
How can I get all file names from the specified directory and print them on console?
Use tIterateToFlow as the following image.
Regards,
Pedro

Re: Purpose of tFlowToIterate and tIterateToFlow

Anonymous — Wed, 27 Jun 2012 11:24:52 GMT

Hi Pedro,
Thank you for the scenarios!
Thanks and Regards,
Pavan

Hi Pavan
Two scenarios would explain these two components.
Scenario 1---tFlowToIterate:
Let's say we have a mysql table called tableA which contains queries like "select * from tableB". I need to extract thses queries from tableA and use them for extracting data from tableB.
tMysqlInput(tableA)--main(row1)-->tFlowToIterate--Iterate-->tMysqlInput_2--main-->tLogRow
In tMysqlInput_2, I type this expression 'row1.query' in the query text field on tMysqlInput_2 for further extraction.
Scenario 2---tIterateToFlow:
tFileList--Iterate-->tIterateToFlow-->tLogRow
How can I get all file names from the specified directory and print them on console?
Use tIterateToFlow as the following image.
Regards,
Pedro

Re: Purpose of tFlowToIterate and tIterateToFlow

Anonymous — Tue, 05 Nov 2013 18:24:08 GMT

hello pedro, very nice your comment, I wonder if I can use the scenario-1 tFlowToIterate and within tMysqlInput use update and delete clauses, thanks

Re: Purpose of tFlowToIterate and tIterateToFlow

Anonymous — Wed, 06 Nov 2013 07:48:25 GMT

Hi,
Do you want to iterate over each of the rows returned from the second query and use them to populate a command to be executed for each row in the first set?
Such as:tMysqlInput_1--main(row1)--tFlowToIterate--tMysqlInput_2--main--tLogRow
on tMysqlInput, set the query like:
"select * from tableName where id="+(Integer)globalMap.get("row1.id")
For your update and delete clauses, txxxrow component is preferred.
Best regards
Sabrina

Re: Purpose of tFlowToIterate and tIterateToFlow

_AnonymousUser — Mon, 04 May 2015 19:20:24 GMT

@xdshi -do you know if it is possible to use the tFlowToIterate to loop through records and create a JSON string every X-Number of records?