Scenario: Creating a line chart to ease trend analysis
This scenario describes a Job that reads data from a CSV file and transforms the data
into a line chart to facilitate trend analysis. The input file records how long (in
minutes) per week a person watches different TV channels over ten weeks, as shown
below:
|
1 2 3 4 5 6 7 8 9 10 11 |
Week;TV_A;TV_B;TV_C 1;327;286;244 2;326;285;243 3;325;283;245 4;323;282;246 5;322;285;248 6;321;288;247 7;322;291;245 8;321;292;244 9;320;293;243 10;319;294;242 |
Because the input file has a different structure than required by the tLineChart component, this use case uses the tMap component to adapt the source data to the three-column
schema of tLineChart so that a temporary CSV file can
be created as the input to the tLineChart
component.
You will usually use the tMap component to adjust
the input schema in accordance with the schema structure of the tLineChart component. For more information about how to
use the tMap component, see
Talend Studio User
Guide and tMap.
To ensure correct generation of the temporary input file, a pre-treatment subjob is
used to delete the temporary file in case it already exists before the main Job is
executed; as this temporary file serves this specific Job only, a post-treatment subjob
is used to deleted it after the main Job is executed.