Talend - generating n multiple rows from 1 row

问题:

Background: I'm using Talend to do something (I guess) that is pretty common: generating multiple rows from one. For example:

ID | Name | DateFrom | DateTo

01 | Marco| 01/01/2014 | 04/01/2014

...could be split into:

new_ID | ID | Name | DateFrom | DateTo

01 | 01 | Marco | 01/01/2014 | 02/01/2014

02 | 01 | Marco | 02/01/2014 | 03/01/2014

03 | 01 | Marco | 03/01/2014 | 04/01/2014

The number of outcoming rows is dynamic, depending on the date period in the original row.

Question: how can I do this? Maybe using tSplitRow? I am going to check those periods with tJavaRow. Any suggestions?

回答1:

Expanding on the answer given by Balazs Gunics

Your first part is to calculate the number of rows one row will become, easy enough with a date diff function on the to and from dates

---

Part 2 is to pass that value to a tFlowToIterate, and pick it up with a tJavaFlex that will use it in its start code to control a for loop:

tJavaFlex start:

int currentId = (Integer)globalMap.get("out1.id");
String currentName = (String)globalMap.get("out1.name");
Long iterations = (Long)globalMap.get("out1.iterations");
Date dateFrom = (java.util.Date)globalMap.get("out1.dateFrom");

for(int i=0; i<((Long)globalMap.get("out1.iterations")); i++) { 

Main

  row2.id = currentId;
  row2.name = currentName;
  row2.dateFrom = TalendDate.addDate(dateFrom, i, "dd");
  row2.dateTo = TalendDate.addDate(dateFrom, i+1, "dd");

End

}

and sample output:

1|Marco|01-01-2014|02-01-2014
1|Marco|02-01-2014|03-01-2014
1|Marco|03-01-2014|04-01-2014
2|Polo|01-01-2014|02-01-2014
2|Polo|02-01-2014|03-01-2014
2|Polo|03-01-2014|04-01-2014
2|Polo|04-01-2014|05-01-2014
2|Polo|05-01-2014|06-01-2014
2|Polo|06-01-2014|07-01-2014
2|Polo|07-01-2014|08-01-2014
2|Polo|08-01-2014|09-01-2014
2|Polo|09-01-2014|10-01-2014
2|Polo|10-01-2014|11-01-2014
2|Polo|11-01-2014|12-01-2014
2|Polo|12-01-2014|13-01-2014
2|Polo|13-01-2014|14-01-2014
2|Polo|14-01-2014|15-01-2014
2|Polo|15-01-2014|16-01-2014
2|Polo|16-01-2014|17-01-2014
2|Polo|17-01-2014|18-01-2014
2|Polo|18-01-2014|19-01-2014
2|Polo|19-01-2014|20-01-2014
2|Polo|20-01-2014|21-01-2014
2|Polo|21-01-2014|22-01-2014
2|Polo|22-01-2014|23-01-2014
2|Polo|23-01-2014|24-01-2014
2|Polo|24-01-2014|25-01-2014
2|Polo|25-01-2014|26-01-2014
2|Polo|26-01-2014|27-01-2014
2|Polo|27-01-2014|28-01-2014
2|Polo|28-01-2014|29-01-2014
2|Polo|29-01-2014|30-01-2014
2|Polo|30-01-2014|31-01-2014
2|Polo|31-01-2014|01-02-2014

回答2:

You can use tJavaFlex to do this.

If you have a small amount of columns the a tFlowToIterate -> tJavaFlex options could be fine.

In the begin part you can start to iterate, and in the main part you assign values to the output schema. If you name your output is row6 then:

row6.id = (String)globalMap.get("id");

and so on.