Join Using a File

In this document, you’ll learn how to use the Join function in Astera Dataprep to combine a dataset from a file source with an existing dataset in your Dataprep Recipe.

Use Case

In this use case, we have a Dataprep Recipe where a Company’s Transactions dataset has been cleansed and aggregated. Now, they want to join it with their Portfolios dataset, which is available in a csv file.

1. To begin, click on the Join option in the toolbar and select File from the drop-down.

1. Alternatively, you can drag and drop the file from the Data Source Browser panel onto the Join object in the Recipe canvas.

1. This will open the Recipe Configuration – Join panel.

1. In this panel, you’ll configure the following options:

• File Location: Choose how you want to locate your file:

  • Browse Path: Use this to manually browse and select your source file.

  • Path from Variable: Use this when your file path is dynamic and parameterized. To learn more about parametrization click here.

  For this use case, we’ll use the Browse Path option.

• Join Dataset: You can provide a custom name for the joined dataset or keep the default name. In this example, we’ll keep the default name.

• Join Type: Choose the type of join you want to perform:

  • Inner: Keeps only the records that have matching values in both datasets.

  • Left Outer: Keeps all records from the current dataset and adds matching data from the joined dataset. Unmatched records from the joined dataset are filled with nulls.

  • Right Outer: Keeps all records from the joined dataset and adds matching data from the current dataset. Unmatched records from the current dataset are filled with nulls.

  • Full Outer: Keeps all records from both datasets. Unmatched values are filled with nulls.

  In our example, we’ll use an Inner join to include only matching records.

• Keys: Specify the key fields that the join will be based on. Astera will auto-detect matching fields, but you can modify them as needed.

  • Left Field: Field from the current dataset.

  • Right Field: Field from the joining dataset.

  In this case, we’ll keep the default key fields selected.

1. Once you’re done, click Apply. The file source dataset will now be joined, and the result will appear in the grid.