Over 46,000+ Business Solution Developers Find answers, ask questions, and connect with our community of business solutions developers, business owners and partners.
The parent key field is the field defined for the current layout table occurrence that is used in a relationship. Say you are on a layout that is linked to a table occurrence named people. All the fields used in relationships in that table are parent key fields. If you move to a layout that is linked to a table occurrence called Invoices, then the key fields in that table are now the parent key fields.
The above picture is taken from the relational graph area of where I store my blog posts.