Materialize/doc/user/layouts/partials/create-source/envelope/upsert/syntax.html

**ENVELOPE UPSERT** [**(VALUE DECODING ERRORS = INLINE)**] | Use the upsert envelope, which uses message keys to handle CRUD operations. To handle value decoding errors, use the `(VALUE DECODING ERRORS = INLINE)` option. For more information, see [Handling upserts](#handling-upserts) and [Value decoding errors](#value-decoding-errors).