Why the identifiers are duplicated in the database? _id & id

[abdonrd]

Why the identifiers are duplicated in the database? _id & id.

[Aurelsicoko]

@abdonrd As you know, Strapi is compatible with Mongo and SQL databases. By convention, the SQL databases are using the id attribute to identify the entries. However, Mongo is using the _id as the identifier. To make the backend and frontend part uniform we partially implement the duplication of the Mongoo _id attribute.

For example, it avoids us to make this everywhere:

const entryId = this.data.user._id || this.data.user.id;

[Aurelsicoko]

The final solution should to automatically handle this in the strapi-mongoose connector to make sure the _id is duplicated and also saved through the id attribute. The codebase has to work with any databases so we have to make that kind of choices. We know it's not perfect but it's an easy and working solution.