1. Elements of UML

UML is a graphical higher-level language used for database modeling and software design; see notes on modeling.

1.1. Classes

Analogous to relations/tables.

Name
Attributes
Methods/primary key

1.1.1. Superclasses

In/complete and disjoint/overlapping.

1.1.2. Subclasses

Inherit attributes from super/parent class, but have own unique attributes and/or unique associations.

1.2. Associations

Captures relationships between objects of two classes. Self-association is possible.

1.2.1. Types of associations

1.2.1.1. Composition

Objects in one class ‘belong’ to objects in another class. Denoted with a solid diamond on the association. Default multiplicity 1..1 . PK not required.

1.2.1.2. Aggregation

Objects might ‘belong’ to, at most, one object of another class. Denoted with an empty diamond on the association. PK required.

1.2.2. Classes for associations

Add attributes to an association, e.g. “Date” and “Decision” to the association “Applied”.

1.2.3. Multiplicity of associations

0..n
0..*
1..1
m..n
m..*

2. Sources

Ambler, S. W. (2005). The elements of UML™ 2.0 style. Cambridge, UK: Cambridge University Press.
https://praveenthomasln.wordpress.com/tag/class-diagrams-in-uml/
Unified Modeling Language