File processing is a day to day task in ETL world, and there is huge need of validation regarding source file format, headers, footers, column name, data type and so on, thanks to tSchemaComplianceCheck component which can do most of the validation like.
But does not support number of columns and column sequence validation, that which we have to manage using java code, in this post I will describe you how to validate column names and their sequence.
This is our final job design.
Let’s start with adding first component to job designer. Add tFileList and configure to get expected files.
Add tFileInputFullRow component and configure as shown in below screen.
Add tMap and connect with main link from tFileinputFullRow component.
Add tFixedFlowInput and connect with lookup link to tMap then configure as follows.
Note: if you have your refrence header row stored in file or database you can use it instead of tFixedFlowInput.
Configure tMap as follows.
Make inner join with your reference line and main line of input.
Add two outputs and named it as “matching” and “reject” respectively.
In the reject output click on setting “catch lookup inner join reject”=true
Add source line to both the flows.
See image for more details.
Add tJava next to tMap and connect with “matching” flow.
Add another tJava next to tMap and connect with “reject” flow.
Add tFileInputDelimited and connect with first tjava using “iterate” flow.
Configure tFileInputDelimited as shown in below image.
Add tLogRow component to see the output from file.
You can see that for each file whole sub job will be executed if it is matching with header row then it will be used for reading.
You can connect reject row to make a note of rejected file based on your requirement.
I am Software consultant with approx 7 years of experience mainly in Business Intelligence and data warehousing assignments using Talend.
Writing is not my passion but i am doing it to help others. if you have any special case where you want me to demonstrate then please post me.