The second part of the article https://www.dataplatformcentral.com//2017/05/30/graph-tables-in-sql-2017/ can be found here
Here I have explained on the concept of Edge Constraints and how they can be used to enforce the relationships between Node tables within an Edge table.
The article also explains on certain system functions which can be used in conjunction with Node and Edge tables to extract the information from pseudo columns in Graph tables which can be utilized in the filter conditions of queries.
