# Working with multiple data sources

A map can only contain one input and output structure, but structures can be combined to use several input and output files.

Talend Data Mapper uses input and output expressions (I/O) to handle multiple data sources. If you use a Job with multiple input or output components linked to a data mapping component, these expressions are automatically added to the map.

For more information about these expressions, see [Input/Output expressions](https://help.qlik.com/talend/en-US/data-mapper-user-guide/8.0/input-output-expressions).

### In this section

* [Combining several inputs into a single output](https://help.qlik.com/talend/en-US/data-mapper-user-guide/8.0-R2025-02/combining-several-inputs-into-single-output)
* [Splitting a file into several outputs](https://help.qlik.com/talend/en-US/data-mapper-user-guide/8.0-R2025-02/splitting-file-into-several-outputs)