👐 Project Settings

• On the top left, next to the three dots, click the settings ⚙️ icon.
• Select single inherited primary key. This detects the primary key from the relational schema and sets them as the _id in MongoDB.
• Optionally, toggle Suggested Mappings on and off.

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If we don't do this we'll have both an autogenerated _id field of type ObjectId and a id field copied from the relational DB. Inheriting the id we copy the existing ids over to MongoDB from our relational DB.