The Collection Property

By default, scalar fields are SV. Assigning an SV scalar field for an existing object replaces the existing value, if present. A scalar field can be declared MV by setting its collection property to true. Example:

<field name="Tags" collection="true" type="TEXT"/>

MV scalar field values are added and removed individually and treated as a set: duplicate values are not stored. This preserves idempotent update semantics: adding the same value twice is a no-op.