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:
For more technologies supported by Talend, see Talend components.
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.