[Rest] backendless 4.0 saving object in table with relation to another table

i just have a parent table called Product
and child table called Shop
and when there was a relation between them (shopId in Product table)
i used this url to add new jsonObject
and i send a json object has the ObjectId of the Child like this

there was a problem the object saved but the shopId would be null ?
any help please


In Backendless 4.0 the relations are no longer saved along with the parent object. Instead, you should use this API: https://backendless.com/docs/rest/doc.html#data_relations_save_update