Create Entity Type Field
Create a field on an entity type. Returns the schema_migration_id of the (already-completed) create migration; fetch it via Get Schema Migration to read the new field id from details.create_field.field_id.
Authorizations
Bearer authentication header of the form Bearer <token>, where <token> is your auth token.
Body
The entity type to create the field on (required).
The unique key for the field. If omitted, derived from the name.
The display name of the field (required).
The data type of the field (required).
DATA_TYPE_UNSPECIFIED, TEXT, NUMBER, BOOL, TIMESTAMP, ENUM, ENTITY_REF, USER_REF, UNIQUE, MULTI_SELECT, FILE Options for ENUM / MULTI_SELECT fields (required for those data types).
Whether this field is the entity type's key (dedup identity) field.
Whether this field is the entity type's display-name field.
For ENTITY_REF fields: the entity type this field references.
Response
Success
Reference to the (COMPLETED) create migration; its details.create_field.field_id is the new field id.

