Pidgin Syntax

Pidgin syntax is very simple. There are two basic ways of relating the entities (things/boxes) in your diagrams. They are generally not used at the same time but you can mix and match the two types in a single diagram too if you want to.


1. Relationship Diagrams

Relationships are described with:

ThingOne relationship ThingTwo, or
ThingOne relationship cardinality ThingTwo

"Cardinality" just means how many, so you can optionally say things like this. E.g.
User has a Car
Car has many Wheel
Car has one SteeringWheel
Wheel has optional FancyHub

There are 11 main relationship verbs and each has their own style of arrow which can have a different tail, head and colour:

Verb Tail Head Colour
is no decorator arrow (solid) red
sees no decorator arrow (solid) green
extends no decorator arrow (solid) green
updates no decorator arrow (solid) blue
from arrow (solid) no decorator red
has no decorator black
uses diamond (outline) arrow (solid) blue
controls diamond (outline) arrow (solid) red
contains diamond (solid) arrow (solid) blue
inherits arrow (solid) no decorator red
association no decorator no decorator

There are 4 main cardinalities which change the style of the relationship arrow(s):

Cardinality Tail Head
many crow's foot
optional circle (outline)
one T shape
a T shape
Relationships examples

2. Flowcharts

Flowcharts can be described very simply and quickly:

StepOne then StepTwo, or
StepOne then Decision (Nb: pidgin doesn't really distinguisgh between decisions and steps; a decision is just another type of step). You can specify any condition following a decision like this:
Decision [optional condition] then StepWhatever

There are 2 words that pidgin considers to be flow actions:

Word Tail Head Colour
then no decorator arrow (solid) blue
next no decorator arrow (solid) blue
Flowcharts examples