It's both a simple and complex feature in Business Central. Simple, because it's an easy and quick way to upload data; complex, because it's also easy to make mistakes that can affect the data.
Here's Microsoft's documentation on it. While it’s not very detailed, it does cover some of the basic aspects
When you add a table to a configuration package and click on Fields, you’ll see a list of the table's fields. Here, you can choose which fields to include in your configuration package for export/import. Although tables often contain many fields, you don’t need to include all of them. This is where the Set Included and Clear Included buttons are useful:
These buttons simply toggle whether all fields in the table are included or not in the configuration package.
Mapping is a separate function. When you select a field and click on Mapping, it opens a new page with two fields: Old Value and New Value. Here, you can specify a value in Old Value that the system will look for during import and convert to the New Value. For example, if you enter "123" as the Old Value and "ABC" as the New Value, every occurrence of "123" in your Excel file being imported will be replaced with "ABC" in the system.
Valentin Castravet
Work: Zander ERP Services
Blog: Dynamics 365 Business Central Insights
LinkedIn: www.linkedin.com/in/valentin-c-0500a247/
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