by Jaromir D.B. Nemec
The supporting functions are defined in the file rvis_supporting_functions.r
The visualisation function getRelVis provides two views. The ordered view classifies the keys in four groups
The keys are ordered based on the group, within the group based on the count of FKs (low count first)
The heat map view is a summary of the ordered view. The two bars on the left show the cardinality of the PK and FK keys in log scale.
The two bars on the right show via a heat map the frequency of the PK and FK keys. The possible empty space below means an idle PK key (PK- group) or PK containing a NULL value.
A dark spot on the top of the PK bar (third bar) signalised duplicated keys in PK. (Be carefull while joining such relation!) Similar a dark spot on the bottom of the FK bar (fourth bar) shows inconsistent FKs (group -FK) - you possible need a full outer join to get all data from such a relation.
last update 15.5.2019
Jaromir D.B. Nemec is a freelancer specializing in data warehouse and integration solutions. He can be reached under http://www.db-nemec.com
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