Hash-encoded columns that are joined by a relationship should share a dictionary

To save space in the Data Model, 2 columns should share a dictionary if and only if:

• Both columns use hash encoding
• Both columns are joined by a one-to-many relationship
• All values in the column on the "many" side of the relationship can be found in the column on the "one" side of the relationship (i.e. no referential integrity violations)
• The column on the "many" side of the relationship is not on the "many" side of any other one-to-many relationship

If any of these conditions is not met, then the columns should revert to not sharing a dictionary.

Currently, the closest that you can come to this is to create a relationship based on integer columns to minimize the size of the dictionary of the column on the "many" side of the relationship.