Martin notation
The Martin notation (also Krähenfußnotation ; English crow's foot notation ) by James Martin, Bachmann and Odell is a notation for semantic data modeling to simplified entity relationship models represent.
It uses so-called crow's feet for a 1: n relationship and is therefore also called crow's foot notation.
The rectangles denote the entity types that are connected to one another by means of relationship lines. For example, “Person” is related to “Place” in the diagram.
The cardinalities (multiplicities) are given by 0 (zero), | (One) or the 
crow's foot (any number). In every relationship there are two cardinalities in a row, which describe the minimum and the maximum occurrence.
The diagrams in the graphic read as follows:
- A person is born in at least one, at most one place.
- A person died in a minimum of zero, at most one place.
- A person goes on vacation in a minimum of zero, a maximum of many places.
- A person has already been to a minimum of one and a maximum of many places.
- In the opposite direction, no statement is made about the cardinality.
The cardinalities in brackets in the diagram (for example "0..n") denote the analog UML notation and do not belong to the Martin notation.