We have a Data Extension with a Primary Key and we are able to insert via REST API a row setting its Primary Key as null.
Until we know, it isn't possible because as Primary Key that field is no nullable but the call through Postman answer with a code 200 and the row is being insert in its first time and update in the following tries.
It appears that the Data Extension has recognized the null value as a PK. The only thing we can do is control it before insert but we need to know if the rows inserted via REST API don't follow the same rules that are setting in the Data Extension, allowing other null fields in non-nullable fields or non number fields in number fields...
Thank you in advance