When using the data model viewer to investigate the relationship between the SalesRepMaster and CustomerMaster tables, the data architect would look at the density of the relationship. Density is a measure of how well the key fields of a table match the key fields of another table. A density of 100% means that all key fields in one table have a match in the other table.

When the density is 100% but the total distinct and present distinct values for the key fields of the related tables do not match, it means that some of the key fields in one table do not have a match in the other table, this is the cause of the issue.