Many-to-Many Relationships

Table of Contents

Intersection Tables

Relational physical models require insertion of an intersection table between every two tables with a many-to-many relationships. All highlighted yellow items below are propagations of main tables primary keys as primary/foreign keys in their required intersection tables. That’s the only kind of data model representation the large majority of data modeling tools will show you:


Minified Shapes

Shapes in Model Xtractor can be expanded (i.e. displayed in full, with their items), collapsed (with just their shape title, hiding the items) or minified. Minified shapes are represented by a circle with an optional icon in it (if you show icons in diagram). Minify all intersection tables and you get the new look below. Minified tables could be considered as not essential to the current view, but they may be required to show passing through relationships:


Chain Relationships

Chains in Model Xtractor are groups of two or more relationship connectors you want to represent with only the first and last shape involved, hiding all passing-through shapes. On metadata import, our framework automatically generates chains for all many-to-many relationships, and these relationships appear instead in our generated models. This means you can remove all together the intersection tables from a diagram, and replace their passing-through connectors with chain connectors between their main shapes. Compare the following economic diagram with the one used as starting point, there is a huge difference: